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[apple/dyld.git] / src / ImageLoaderMachO.cpp
1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
2 *
3 * Copyright (c) 2004-2010 Apple Inc. All rights reserved.
4 *
5 * @APPLE_LICENSE_HEADER_START@
6 *
7 * This file contains Original Code and/or Modifications of Original Code
8 * as defined in and that are subject to the Apple Public Source License
9 * Version 2.0 (the 'License'). You may not use this file except in
10 * compliance with the License. Please obtain a copy of the License at
11 * http://www.opensource.apple.com/apsl/ and read it before using this
12 * file.
13 *
14 * The Original Code and all software distributed under the License are
15 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
16 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
17 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
19 * Please see the License for the specific language governing rights and
20 * limitations under the License.
21 *
22 * @APPLE_LICENSE_HEADER_END@
23 */
24
25 // work around until conformance work is complete rdar://problem/4508801
26 #define __srr0 srr0
27 #define __eip eip
28 #define __rip rip
29
30 #define __STDC_LIMIT_MACROS
31 #include <string.h>
32 #include <fcntl.h>
33 #include <errno.h>
34 #include <sys/types.h>
35 #include <sys/fcntl.h>
36 #include <sys/stat.h>
37 #include <sys/mman.h>
38 #include <mach/mach.h>
39 #include <mach/thread_status.h>
40 #include <mach-o/loader.h>
41 #include <mach-o/nlist.h>
42 #include <sys/sysctl.h>
43 #include <sys/syscall.h>
44 #include <libkern/OSAtomic.h>
45 #include <libkern/OSCacheControl.h>
46 #include <stdint.h>
47 #include <System/sys/codesign.h>
48
49 #include "ImageLoaderMachO.h"
50 #include "ImageLoaderMachOCompressed.h"
51 #if SUPPORT_CLASSIC_MACHO
52 #include "ImageLoaderMachOClassic.h"
53 #endif
54 #include "mach-o/dyld_images.h"
55 #include "Tracing.h"
56 #include "dyld.h"
57
58 // <rdar://problem/8718137> use stack guard random value to add padding between dylibs
59 extern "C" long __stack_chk_guard;
60
61 #ifndef LC_LOAD_UPWARD_DYLIB
62 #define LC_LOAD_UPWARD_DYLIB (0x23|LC_REQ_DYLD) /* load of dylib whose initializers run later */
63 #endif
64
65 #ifndef LC_VERSION_MIN_TVOS
66 #define LC_VERSION_MIN_TVOS 0x2F
67 #endif
68
69 #ifndef LC_VERSION_MIN_WATCHOS
70 #define LC_VERSION_MIN_WATCHOS 0x30
71 #endif
72
73 #ifndef LC_BUILD_VERSION
74 #define LC_BUILD_VERSION 0x32 /* build for platform min OS version */
75
76 /*
77 * The build_version_command contains the min OS version on which this
78 * binary was built to run for its platform. The list of known platforms and
79 * tool values following it.
80 */
81 struct build_version_command {
82 uint32_t cmd; /* LC_BUILD_VERSION */
83 uint32_t cmdsize; /* sizeof(struct build_version_command) plus */
84 /* ntools * sizeof(struct build_tool_version) */
85 uint32_t platform; /* platform */
86 uint32_t minos; /* X.Y.Z is encoded in nibbles xxxx.yy.zz */
87 uint32_t sdk; /* X.Y.Z is encoded in nibbles xxxx.yy.zz */
88 uint32_t ntools; /* number of tool entries following this */
89 };
90
91 struct build_tool_version {
92 uint32_t tool; /* enum for the tool */
93 uint32_t version; /* version number of the tool */
94 };
95
96 /* Known values for the platform field above. */
97 #define PLATFORM_MACOS 1
98 #define PLATFORM_IOS 2
99 #define PLATFORM_TVOS 3
100 #define PLATFORM_WATCHOS 4
101 #define PLATFORM_BRIDGEOS 5
102
103 /* Known values for the tool field above. */
104 #define TOOL_CLANG 1
105 #define TOOL_SWIFT 2
106 #define TOOL_LD 3
107 #endif
108
109
110
111 #if TARGET_IPHONE_SIMULATOR
112 #define LIBSYSTEM_DYLIB_PATH "/usr/lib/libSystem.dylib"
113 #else
114 #define LIBSYSTEM_DYLIB_PATH "/usr/lib/libSystem.B.dylib"
115 #endif
116
117 // relocation_info.r_length field has value 3 for 64-bit executables and value 2 for 32-bit executables
118 #if __LP64__
119 #define LC_SEGMENT_COMMAND LC_SEGMENT_64
120 #define LC_ROUTINES_COMMAND LC_ROUTINES_64
121 #define LC_SEGMENT_COMMAND_WRONG LC_SEGMENT
122 struct macho_segment_command : public segment_command_64 {};
123 struct macho_section : public section_64 {};
124 struct macho_routines_command : public routines_command_64 {};
125 #else
126 #define LC_SEGMENT_COMMAND LC_SEGMENT
127 #define LC_ROUTINES_COMMAND LC_ROUTINES
128 #define LC_SEGMENT_COMMAND_WRONG LC_SEGMENT_64
129 struct macho_segment_command : public segment_command {};
130 struct macho_section : public section {};
131 struct macho_routines_command : public routines_command {};
132 #endif
133
134 uint32_t ImageLoaderMachO::fgSymbolTableBinarySearchs = 0;
135
136
137 ImageLoaderMachO::ImageLoaderMachO(const macho_header* mh, const char* path, unsigned int segCount,
138 uint32_t segOffsets[], unsigned int libCount)
139 : ImageLoader(path, libCount), fCoveredCodeLength(0), fMachOData((uint8_t*)mh), fLinkEditBase(NULL), fSlide(0),
140 fEHFrameSectionOffset(0), fUnwindInfoSectionOffset(0), fDylibIDOffset(0),
141 fSegmentsCount(segCount), fIsSplitSeg(false), fInSharedCache(false),
142 #if TEXT_RELOC_SUPPORT
143 fTextSegmentRebases(false),
144 fTextSegmentBinds(false),
145 #endif
146 #if __i386__
147 fReadOnlyImportSegment(false),
148 #endif
149 fHasSubLibraries(false), fHasSubUmbrella(false), fInUmbrella(false), fHasDOFSections(false), fHasDashInit(false),
150 fHasInitializers(false), fHasTerminators(false), fNotifyObjC(false), fRetainForObjC(false), fRegisteredAsRequiresCoalescing(false)
151 {
152 fIsSplitSeg = ((mh->flags & MH_SPLIT_SEGS) != 0);
153
154 // construct SegmentMachO object for each LC_SEGMENT cmd using "placement new" to put
155 // each SegmentMachO object in array at end of ImageLoaderMachO object
156 const uint32_t cmd_count = mh->ncmds;
157 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
158 const struct load_command* cmd = cmds;
159 for (uint32_t i = 0, segIndex=0; i < cmd_count; ++i) {
160 if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
161 const struct macho_segment_command* segCmd = (struct macho_segment_command*)cmd;
162 // ignore zero-sized segments
163 if ( segCmd->vmsize != 0 ) {
164 // record offset of load command
165 segOffsets[segIndex++] = (uint32_t)((uint8_t*)segCmd - fMachOData);
166 }
167 }
168 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
169 }
170
171 }
172
173 #if __MAC_OS_X_VERSION_MIN_REQUIRED
174 static uintptr_t pageAlign(uintptr_t value)
175 {
176 return (value + 4095) & (-4096);
177 }
178 #endif
179
180 // determine if this mach-o file has classic or compressed LINKEDIT and number of segments it has
181 void ImageLoaderMachO::sniffLoadCommands(const macho_header* mh, const char* path, bool inCache, bool* compressed,
182 unsigned int* segCount, unsigned int* libCount, const LinkContext& context,
183 const linkedit_data_command** codeSigCmd,
184 const encryption_info_command** encryptCmd)
185 {
186 *compressed = false;
187 *segCount = 0;
188 *libCount = 0;
189 *codeSigCmd = NULL;
190 *encryptCmd = NULL;
191
192 const uint32_t cmd_count = mh->ncmds;
193 const uint32_t sizeofcmds = mh->sizeofcmds;
194 if ( sizeofcmds > (MAX_MACH_O_HEADER_AND_LOAD_COMMANDS_SIZE-sizeof(macho_header)) )
195 dyld::throwf("malformed mach-o: load commands size (%u) > %u", sizeofcmds, MAX_MACH_O_HEADER_AND_LOAD_COMMANDS_SIZE);
196 if ( cmd_count > (sizeofcmds/sizeof(load_command)) )
197 dyld::throwf("malformed mach-o: ncmds (%u) too large to fit in sizeofcmds (%u)", cmd_count, sizeofcmds);
198 const struct load_command* const startCmds = (struct load_command*)(((uint8_t*)mh) + sizeof(macho_header));
199 const struct load_command* const endCmds = (struct load_command*)(((uint8_t*)mh) + sizeof(macho_header) + sizeofcmds);
200 const struct load_command* cmd = startCmds;
201 bool foundLoadCommandSegment = false;
202 const macho_segment_command* linkeditSegCmd = NULL;
203 const macho_segment_command* startOfFileSegCmd = NULL;
204 const dyld_info_command* dyldInfoCmd = NULL;
205 const symtab_command* symTabCmd = NULL;
206 const dysymtab_command* dynSymbTabCmd = NULL;
207 for (uint32_t i = 0; i < cmd_count; ++i) {
208 uint32_t cmdLength = cmd->cmdsize;
209 const macho_segment_command* segCmd;
210 const dylib_command* dylibCmd;
211 if ( cmdLength < 8 ) {
212 dyld::throwf("malformed mach-o image: load command #%d length (%u) too small in %s",
213 i, cmdLength, path);
214 }
215 const struct load_command* const nextCmd = (const struct load_command*)(((char*)cmd)+cmdLength);
216 if ( (nextCmd > endCmds) || (nextCmd < cmd) ) {
217 dyld::throwf("malformed mach-o image: load command #%d length (%u) would exceed sizeofcmds (%u) in %s",
218 i, cmdLength, mh->sizeofcmds, path);
219 }
220 switch (cmd->cmd) {
221 case LC_DYLD_INFO:
222 case LC_DYLD_INFO_ONLY:
223 if ( cmd->cmdsize != sizeof(dyld_info_command) )
224 throw "malformed mach-o image: LC_DYLD_INFO size wrong";
225 dyldInfoCmd = (struct dyld_info_command*)cmd;
226 *compressed = true;
227 break;
228 case LC_SEGMENT_COMMAND:
229 segCmd = (struct macho_segment_command*)cmd;
230 #if __MAC_OS_X_VERSION_MIN_REQUIRED
231 // rdar://problem/19617624 allow unmapped segments on OSX (but not iOS)
232 if ( ((segCmd->filesize) > pageAlign(segCmd->vmsize)) && (segCmd->vmsize != 0) )
233 #else
234 // <rdar://problem/19986776> dyld should support non-allocatable __LLVM segment
235 if ( (segCmd->filesize > segCmd->vmsize) && ((segCmd->vmsize != 0) || ((segCmd->flags & SG_NORELOC) == 0)) )
236 #endif
237 dyld::throwf("malformed mach-o image: segment load command %s filesize (0x%0lX) is larger than vmsize (0x%0lX)", segCmd->segname, (long)segCmd->filesize , (long)segCmd->vmsize );
238 if ( cmd->cmdsize < sizeof(macho_segment_command) )
239 throw "malformed mach-o image: LC_SEGMENT size too small";
240 if ( cmd->cmdsize != (sizeof(macho_segment_command) + segCmd->nsects * sizeof(macho_section)) )
241 throw "malformed mach-o image: LC_SEGMENT size wrong for number of sections";
242 // ignore zero-sized segments
243 if ( segCmd->vmsize != 0 )
244 *segCount += 1;
245 if ( strcmp(segCmd->segname, "__LINKEDIT") == 0 ) {
246 #if TARGET_IPHONE_SIMULATOR
247 // Note: should check on all platforms that __LINKEDIT is read-only, but <rdar://problem/22637626&22525618>
248 if ( segCmd->initprot != VM_PROT_READ )
249 throw "malformed mach-o image: __LINKEDIT segment does not have read-only permissions";
250 #endif
251 if ( segCmd->fileoff == 0 )
252 throw "malformed mach-o image: __LINKEDIT has fileoff==0 which overlaps mach_header";
253 if ( linkeditSegCmd != NULL )
254 throw "malformed mach-o image: multiple __LINKEDIT segments";
255 linkeditSegCmd = segCmd;
256 }
257 else {
258 if ( segCmd->initprot & 0xFFFFFFF8 )
259 dyld::throwf("malformed mach-o image: %s segment has invalid permission bits (0x%X) in initprot", segCmd->segname, segCmd->initprot);
260 if ( segCmd->maxprot & 0xFFFFFFF8 )
261 dyld::throwf("malformed mach-o image: %s segment has invalid permission bits (0x%X) in maxprot", segCmd->segname, segCmd->maxprot);
262 if ( (segCmd->initprot != 0) && ((segCmd->initprot & VM_PROT_READ) == 0) )
263 dyld::throwf("malformed mach-o image: %s segment is not mapped readable", segCmd->segname);
264 }
265 if ( (segCmd->fileoff == 0) && (segCmd->filesize != 0) ) {
266 if ( (segCmd->initprot & VM_PROT_READ) == 0 )
267 dyld::throwf("malformed mach-o image: %s segment maps start of file but is not readable", segCmd->segname);
268 if ( (segCmd->initprot & VM_PROT_WRITE) == VM_PROT_WRITE ) {
269 if ( context.strictMachORequired )
270 dyld::throwf("malformed mach-o image: %s segment maps start of file but is writable", segCmd->segname);
271 }
272 if ( segCmd->filesize < (sizeof(macho_header) + mh->sizeofcmds) )
273 dyld::throwf("malformed mach-o image: %s segment does not map all of load commands", segCmd->segname);
274 if ( startOfFileSegCmd != NULL )
275 dyld::throwf("malformed mach-o image: multiple segments map start of file: %s %s", startOfFileSegCmd->segname, segCmd->segname);
276 startOfFileSegCmd = segCmd;
277 }
278 if ( context.strictMachORequired ) {
279 uintptr_t vmStart = segCmd->vmaddr;
280 uintptr_t vmSize = segCmd->vmsize;
281 uintptr_t vmEnd = vmStart + vmSize;
282 uintptr_t fileStart = segCmd->fileoff;
283 uintptr_t fileSize = segCmd->filesize;
284 if ( (intptr_t)(vmSize) < 0 )
285 dyld::throwf("malformed mach-o image: segment load command %s vmsize too large in %s", segCmd->segname, path);
286 if ( vmStart > vmEnd )
287 dyld::throwf("malformed mach-o image: segment load command %s wraps around address space", segCmd->segname);
288 if ( vmSize != fileSize ) {
289 if ( segCmd->initprot == 0 ) {
290 // allow: fileSize == 0 && initprot == 0 e.g. __PAGEZERO
291 // allow: vmSize == 0 && initprot == 0 e.g. __LLVM
292 if ( (fileSize != 0) && (vmSize != 0) )
293 dyld::throwf("malformed mach-o image: unaccessable segment %s has non-zero filesize and vmsize", segCmd->segname);
294 }
295 else {
296 // allow: vmSize > fileSize && initprot != X e.g. __DATA
297 if ( vmSize < fileSize ) {
298 dyld::throwf("malformed mach-o image: segment %s has vmsize < filesize", segCmd->segname);
299 }
300 if ( segCmd->initprot & VM_PROT_EXECUTE ) {
301 dyld::throwf("malformed mach-o image: segment %s has vmsize != filesize and is executable", segCmd->segname);
302 }
303 }
304 }
305 if ( inCache ) {
306 if ( (fileSize != 0) && (segCmd->initprot == (VM_PROT_READ | VM_PROT_EXECUTE)) ) {
307 if ( foundLoadCommandSegment )
308 throw "load commands in multiple segments";
309 foundLoadCommandSegment = true;
310 }
311 }
312 else if ( (fileStart < mh->sizeofcmds) && (fileSize != 0) ) {
313 // <rdar://problem/7942521> all load commands must be in an executable segment
314 if ( (fileStart != 0) || (fileSize < (mh->sizeofcmds+sizeof(macho_header))) )
315 dyld::throwf("malformed mach-o image: segment %s does not span all load commands", segCmd->segname);
316 if ( segCmd->initprot != (VM_PROT_READ | VM_PROT_EXECUTE) )
317 dyld::throwf("malformed mach-o image: load commands found in segment %s with wrong permissions", segCmd->segname);
318 if ( foundLoadCommandSegment )
319 throw "load commands in multiple segments";
320 foundLoadCommandSegment = true;
321 }
322
323 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)segCmd + sizeof(struct macho_segment_command));
324 const struct macho_section* const sectionsEnd = &sectionsStart[segCmd->nsects];
325 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
326 if (!inCache && sect->offset != 0 && ((sect->offset + sect->size) > (segCmd->fileoff + segCmd->filesize)))
327 dyld::throwf("malformed mach-o image: section %s,%s of '%s' exceeds segment %s booundary", sect->segname, sect->sectname, path, segCmd->segname);
328 }
329 }
330 break;
331 case LC_SEGMENT_COMMAND_WRONG:
332 dyld::throwf("malformed mach-o image: wrong LC_SEGMENT[_64] for architecture");
333 break;
334 case LC_LOAD_DYLIB:
335 case LC_LOAD_WEAK_DYLIB:
336 case LC_REEXPORT_DYLIB:
337 case LC_LOAD_UPWARD_DYLIB:
338 *libCount += 1;
339 // fall thru
340 case LC_ID_DYLIB:
341 dylibCmd = (dylib_command*)cmd;
342 if ( dylibCmd->dylib.name.offset > cmdLength )
343 dyld::throwf("malformed mach-o image: dylib load command #%d has offset (%u) outside its size (%u)", i, dylibCmd->dylib.name.offset, cmdLength);
344 if ( (dylibCmd->dylib.name.offset + strlen((char*)dylibCmd + dylibCmd->dylib.name.offset) + 1) > cmdLength )
345 dyld::throwf("malformed mach-o image: dylib load command #%d string extends beyond end of load command", i);
346 break;
347 case LC_CODE_SIGNATURE:
348 if ( cmd->cmdsize != sizeof(linkedit_data_command) )
349 throw "malformed mach-o image: LC_CODE_SIGNATURE size wrong";
350 // <rdar://problem/22799652> only support one LC_CODE_SIGNATURE per image
351 if ( *codeSigCmd != NULL )
352 throw "malformed mach-o image: multiple LC_CODE_SIGNATURE load commands";
353 *codeSigCmd = (struct linkedit_data_command*)cmd;
354 break;
355 case LC_ENCRYPTION_INFO:
356 if ( cmd->cmdsize != sizeof(encryption_info_command) )
357 throw "malformed mach-o image: LC_ENCRYPTION_INFO size wrong";
358 // <rdar://problem/22799652> only support one LC_ENCRYPTION_INFO per image
359 if ( *encryptCmd != NULL )
360 throw "malformed mach-o image: multiple LC_ENCRYPTION_INFO load commands";
361 *encryptCmd = (encryption_info_command*)cmd;
362 break;
363 case LC_ENCRYPTION_INFO_64:
364 if ( cmd->cmdsize != sizeof(encryption_info_command_64) )
365 throw "malformed mach-o image: LC_ENCRYPTION_INFO_64 size wrong";
366 // <rdar://problem/22799652> only support one LC_ENCRYPTION_INFO_64 per image
367 if ( *encryptCmd != NULL )
368 throw "malformed mach-o image: multiple LC_ENCRYPTION_INFO_64 load commands";
369 *encryptCmd = (encryption_info_command*)cmd;
370 break;
371 case LC_SYMTAB:
372 if ( cmd->cmdsize != sizeof(symtab_command) )
373 throw "malformed mach-o image: LC_SYMTAB size wrong";
374 symTabCmd = (symtab_command*)cmd;
375 break;
376 case LC_DYSYMTAB:
377 if ( cmd->cmdsize != sizeof(dysymtab_command) )
378 throw "malformed mach-o image: LC_DYSYMTAB size wrong";
379 dynSymbTabCmd = (dysymtab_command*)cmd;
380 break;
381 #if __MAC_OS_X_VERSION_MIN_REQUIRED
382 // <rdar://problem/26797345> error when loading iOS Simulator mach-o binary into macOS process
383 case LC_VERSION_MIN_WATCHOS:
384 case LC_VERSION_MIN_TVOS:
385 case LC_VERSION_MIN_IPHONEOS:
386 throw "mach-o, but built for simulator (not macOS)";
387 break;
388 #endif
389 }
390 cmd = nextCmd;
391 }
392
393 if ( context.strictMachORequired && !foundLoadCommandSegment )
394 throw "load commands not in a segment";
395 if ( linkeditSegCmd == NULL )
396 throw "malformed mach-o image: missing __LINKEDIT segment";
397 if ( !inCache && (startOfFileSegCmd == NULL) )
398 throw "malformed mach-o image: missing __TEXT segment that maps start of file";
399 // <rdar://problem/13145644> verify every segment does not overlap another segment
400 if ( context.strictMachORequired ) {
401 uintptr_t lastFileStart = 0;
402 uintptr_t linkeditFileStart = 0;
403 const struct load_command* cmd1 = startCmds;
404 for (uint32_t i = 0; i < cmd_count; ++i) {
405 if ( cmd1->cmd == LC_SEGMENT_COMMAND ) {
406 struct macho_segment_command* segCmd1 = (struct macho_segment_command*)cmd1;
407 uintptr_t vmStart1 = segCmd1->vmaddr;
408 uintptr_t vmEnd1 = segCmd1->vmaddr + segCmd1->vmsize;
409 uintptr_t fileStart1 = segCmd1->fileoff;
410 uintptr_t fileEnd1 = segCmd1->fileoff + segCmd1->filesize;
411
412 if (fileStart1 > lastFileStart)
413 lastFileStart = fileStart1;
414
415 if ( strcmp(&segCmd1->segname[0], "__LINKEDIT") == 0 ) {
416 linkeditFileStart = fileStart1;
417 }
418
419 const struct load_command* cmd2 = startCmds;
420 for (uint32_t j = 0; j < cmd_count; ++j) {
421 if ( cmd2 == cmd1 )
422 continue;
423 if ( cmd2->cmd == LC_SEGMENT_COMMAND ) {
424 struct macho_segment_command* segCmd2 = (struct macho_segment_command*)cmd2;
425 uintptr_t vmStart2 = segCmd2->vmaddr;
426 uintptr_t vmEnd2 = segCmd2->vmaddr + segCmd2->vmsize;
427 uintptr_t fileStart2 = segCmd2->fileoff;
428 uintptr_t fileEnd2 = segCmd2->fileoff + segCmd2->filesize;
429 if ( ((vmStart2 <= vmStart1) && (vmEnd2 > vmStart1) && (vmEnd1 > vmStart1))
430 || ((vmStart2 >= vmStart1) && (vmStart2 < vmEnd1) && (vmEnd2 > vmStart2)) )
431 dyld::throwf("malformed mach-o image: segment %s vm overlaps segment %s", segCmd1->segname, segCmd2->segname);
432 if ( ((fileStart2 <= fileStart1) && (fileEnd2 > fileStart1) && (fileEnd1 > fileStart1))
433 || ((fileStart2 >= fileStart1) && (fileStart2 < fileEnd1) && (fileEnd2 > fileStart2)) )
434 dyld::throwf("malformed mach-o image: segment %s file content overlaps segment %s", segCmd1->segname, segCmd2->segname);
435 }
436 cmd2 = (const struct load_command*)(((char*)cmd2)+cmd2->cmdsize);
437 }
438 }
439 cmd1 = (const struct load_command*)(((char*)cmd1)+cmd1->cmdsize);
440 }
441
442 if (lastFileStart != linkeditFileStart)
443 dyld::throwf("malformed mach-o image: __LINKEDIT must be last segment");
444 }
445
446 // validate linkedit content
447 if ( (dyldInfoCmd == NULL) && (symTabCmd == NULL) )
448 throw "malformed mach-o image: missing LC_SYMTAB or LC_DYLD_INFO";
449 if ( dynSymbTabCmd == NULL )
450 throw "malformed mach-o image: missing LC_DYSYMTAB";
451
452 uint32_t linkeditFileOffsetStart = (uint32_t)linkeditSegCmd->fileoff;
453 uint32_t linkeditFileOffsetEnd = (uint32_t)linkeditSegCmd->fileoff + (uint32_t)linkeditSegCmd->filesize;
454
455 if ( !inCache && (dyldInfoCmd != NULL) && context.strictMachORequired ) {
456 // validate all LC_DYLD_INFO chunks fit in LINKEDIT and don't overlap
457 uint32_t offset = linkeditFileOffsetStart;
458 if ( dyldInfoCmd->rebase_size != 0 ) {
459 if ( dyldInfoCmd->rebase_size & 0x80000000 )
460 throw "malformed mach-o image: dyld rebase info size overflow";
461 if ( dyldInfoCmd->rebase_off < offset )
462 throw "malformed mach-o image: dyld rebase info underruns __LINKEDIT";
463 offset = dyldInfoCmd->rebase_off + dyldInfoCmd->rebase_size;
464 if ( offset > linkeditFileOffsetEnd )
465 throw "malformed mach-o image: dyld rebase info overruns __LINKEDIT";
466 }
467 if ( dyldInfoCmd->bind_size != 0 ) {
468 if ( dyldInfoCmd->bind_size & 0x80000000 )
469 throw "malformed mach-o image: dyld bind info size overflow";
470 if ( dyldInfoCmd->bind_off < offset )
471 throw "malformed mach-o image: dyld bind info overlaps rebase info";
472 offset = dyldInfoCmd->bind_off + dyldInfoCmd->bind_size;
473 if ( offset > linkeditFileOffsetEnd )
474 throw "malformed mach-o image: dyld bind info overruns __LINKEDIT";
475 }
476 if ( dyldInfoCmd->weak_bind_size != 0 ) {
477 if ( dyldInfoCmd->weak_bind_size & 0x80000000 )
478 throw "malformed mach-o image: dyld weak bind info size overflow";
479 if ( dyldInfoCmd->weak_bind_off < offset )
480 throw "malformed mach-o image: dyld weak bind info overlaps bind info";
481 offset = dyldInfoCmd->weak_bind_off + dyldInfoCmd->weak_bind_size;
482 if ( offset > linkeditFileOffsetEnd )
483 throw "malformed mach-o image: dyld weak bind info overruns __LINKEDIT";
484 }
485 if ( dyldInfoCmd->lazy_bind_size != 0 ) {
486 if ( dyldInfoCmd->lazy_bind_size & 0x80000000 )
487 throw "malformed mach-o image: dyld lazy bind info size overflow";
488 if ( dyldInfoCmd->lazy_bind_off < offset )
489 throw "malformed mach-o image: dyld lazy bind info overlaps weak bind info";
490 offset = dyldInfoCmd->lazy_bind_off + dyldInfoCmd->lazy_bind_size;
491 if ( offset > linkeditFileOffsetEnd )
492 throw "malformed mach-o image: dyld lazy bind info overruns __LINKEDIT";
493 }
494 if ( dyldInfoCmd->export_size != 0 ) {
495 if ( dyldInfoCmd->export_size & 0x80000000 )
496 throw "malformed mach-o image: dyld export info size overflow";
497 if ( dyldInfoCmd->export_off < offset )
498 throw "malformed mach-o image: dyld export info overlaps lazy bind info";
499 offset = dyldInfoCmd->export_off + dyldInfoCmd->export_size;
500 if ( offset > linkeditFileOffsetEnd )
501 throw "malformed mach-o image: dyld export info overruns __LINKEDIT";
502 }
503 }
504
505 if ( symTabCmd != NULL ) {
506 // validate symbol table fits in LINKEDIT
507 if ( symTabCmd->symoff < linkeditFileOffsetStart )
508 throw "malformed mach-o image: symbol table underruns __LINKEDIT";
509 if ( symTabCmd->nsyms > 0x10000000 )
510 throw "malformed mach-o image: symbol table too large";
511 uint32_t symbolsSize = symTabCmd->nsyms * sizeof(macho_nlist);
512 if ( symbolsSize > linkeditSegCmd->filesize )
513 throw "malformed mach-o image: symbol table overruns __LINKEDIT";
514 if ( symTabCmd->symoff + symbolsSize < symTabCmd->symoff )
515 throw "malformed mach-o image: symbol table size wraps";
516 if ( symTabCmd->symoff + symbolsSize > symTabCmd->stroff )
517 throw "malformed mach-o image: symbol table overlaps symbol strings";
518 if ( symTabCmd->stroff + symTabCmd->strsize < symTabCmd->stroff )
519 throw "malformed mach-o image: symbol string size wraps";
520 if ( symTabCmd->stroff + symTabCmd->strsize > linkeditFileOffsetEnd ) {
521 // <rdar://problem/24220313> let old apps overflow as long as it stays within mapped page
522 if ( context.strictMachORequired || (symTabCmd->stroff + symTabCmd->strsize > ((linkeditFileOffsetEnd + 4095) & (-4096))) )
523 throw "malformed mach-o image: symbol strings overrun __LINKEDIT";
524 }
525 // validate indirect symbol table
526 if ( dynSymbTabCmd->nindirectsyms != 0 ) {
527 if ( dynSymbTabCmd->indirectsymoff < linkeditFileOffsetStart )
528 throw "malformed mach-o image: indirect symbol table underruns __LINKEDIT";
529 if ( dynSymbTabCmd->nindirectsyms > 0x10000000 )
530 throw "malformed mach-o image: indirect symbol table too large";
531 uint32_t indirectTableSize = dynSymbTabCmd->nindirectsyms * sizeof(uint32_t);
532 if ( indirectTableSize > linkeditSegCmd->filesize )
533 throw "malformed mach-o image: indirect symbol table overruns __LINKEDIT";
534 if ( dynSymbTabCmd->indirectsymoff + indirectTableSize < dynSymbTabCmd->indirectsymoff )
535 throw "malformed mach-o image: indirect symbol table size wraps";
536 if ( context.strictMachORequired && (dynSymbTabCmd->indirectsymoff + indirectTableSize > symTabCmd->stroff) )
537 throw "malformed mach-o image: indirect symbol table overruns string pool";
538 }
539 if ( (dynSymbTabCmd->nlocalsym > symTabCmd->nsyms) || (dynSymbTabCmd->ilocalsym > symTabCmd->nsyms) )
540 throw "malformed mach-o image: indirect symbol table local symbol count exceeds total symbols";
541 if ( dynSymbTabCmd->ilocalsym + dynSymbTabCmd->nlocalsym < dynSymbTabCmd->ilocalsym )
542 throw "malformed mach-o image: indirect symbol table local symbol count wraps";
543 if ( (dynSymbTabCmd->nextdefsym > symTabCmd->nsyms) || (dynSymbTabCmd->iextdefsym > symTabCmd->nsyms) )
544 throw "malformed mach-o image: indirect symbol table extern symbol count exceeds total symbols";
545 if ( dynSymbTabCmd->iextdefsym + dynSymbTabCmd->nextdefsym < dynSymbTabCmd->iextdefsym )
546 throw "malformed mach-o image: indirect symbol table extern symbol count wraps";
547 if ( (dynSymbTabCmd->nundefsym > symTabCmd->nsyms) || (dynSymbTabCmd->iundefsym > symTabCmd->nsyms) )
548 throw "malformed mach-o image: indirect symbol table undefined symbol count exceeds total symbols";
549 if ( dynSymbTabCmd->iundefsym + dynSymbTabCmd->nundefsym < dynSymbTabCmd->iundefsym )
550 throw "malformed mach-o image: indirect symbol table undefined symbol count wraps";
551 }
552
553
554 // fSegmentsArrayCount is only 8-bits
555 if ( *segCount > 255 )
556 dyld::throwf("malformed mach-o image: more than 255 segments in %s", path);
557
558 // fSegmentsArrayCount is only 8-bits
559 if ( *libCount > 4095 )
560 dyld::throwf("malformed mach-o image: more than 4095 dependent libraries in %s", path);
561
562 if ( needsAddedLibSystemDepency(*libCount, mh) )
563 *libCount = 1;
564 }
565
566
567
568 // create image for main executable
569 ImageLoader* ImageLoaderMachO::instantiateMainExecutable(const macho_header* mh, uintptr_t slide, const char* path, const LinkContext& context)
570 {
571 //dyld::log("ImageLoader=%ld, ImageLoaderMachO=%ld, ImageLoaderMachOClassic=%ld, ImageLoaderMachOCompressed=%ld\n",
572 // sizeof(ImageLoader), sizeof(ImageLoaderMachO), sizeof(ImageLoaderMachOClassic), sizeof(ImageLoaderMachOCompressed));
573 bool compressed;
574 unsigned int segCount;
575 unsigned int libCount;
576 const linkedit_data_command* codeSigCmd;
577 const encryption_info_command* encryptCmd;
578 sniffLoadCommands(mh, path, false, &compressed, &segCount, &libCount, context, &codeSigCmd, &encryptCmd);
579 // instantiate concrete class based on content of load commands
580 if ( compressed )
581 return ImageLoaderMachOCompressed::instantiateMainExecutable(mh, slide, path, segCount, libCount, context);
582 else
583 #if SUPPORT_CLASSIC_MACHO
584 return ImageLoaderMachOClassic::instantiateMainExecutable(mh, slide, path, segCount, libCount, context);
585 #else
586 throw "missing LC_DYLD_INFO load command";
587 #endif
588 }
589
590
591 // create image by mapping in a mach-o file
592 ImageLoader* ImageLoaderMachO::instantiateFromFile(const char* path, int fd, const uint8_t firstPages[], size_t firstPagesSize, uint64_t offsetInFat,
593 uint64_t lenInFat, const struct stat& info, const LinkContext& context)
594 {
595 bool compressed;
596 unsigned int segCount;
597 unsigned int libCount;
598 const linkedit_data_command* codeSigCmd;
599 const encryption_info_command* encryptCmd;
600 sniffLoadCommands((const macho_header*)firstPages, path, false, &compressed, &segCount, &libCount, context, &codeSigCmd, &encryptCmd);
601 // instantiate concrete class based on content of load commands
602 if ( compressed )
603 return ImageLoaderMachOCompressed::instantiateFromFile(path, fd, firstPages, firstPagesSize, offsetInFat, lenInFat, info, segCount, libCount, codeSigCmd, encryptCmd, context);
604 else
605 #if SUPPORT_CLASSIC_MACHO
606 return ImageLoaderMachOClassic::instantiateFromFile(path, fd, firstPages, firstPagesSize, offsetInFat, lenInFat, info, segCount, libCount, codeSigCmd, context);
607 #else
608 throw "missing LC_DYLD_INFO load command";
609 #endif
610 }
611
612 // create image by using cached mach-o file
613 ImageLoader* ImageLoaderMachO::instantiateFromCache(const macho_header* mh, const char* path, long slide, const struct stat& info, const LinkContext& context)
614 {
615 // instantiate right concrete class
616 bool compressed;
617 unsigned int segCount;
618 unsigned int libCount;
619 const linkedit_data_command* codeSigCmd;
620 const encryption_info_command* encryptCmd;
621 sniffLoadCommands(mh, path, true, &compressed, &segCount, &libCount, context, &codeSigCmd, &encryptCmd);
622 // instantiate concrete class based on content of load commands
623 if ( compressed )
624 return ImageLoaderMachOCompressed::instantiateFromCache(mh, path, slide, info, segCount, libCount, context);
625 else
626 #if SUPPORT_CLASSIC_MACHO
627 return ImageLoaderMachOClassic::instantiateFromCache(mh, path, slide, info, segCount, libCount, context);
628 #else
629 throw "missing LC_DYLD_INFO load command";
630 #endif
631 }
632
633 // create image by copying an in-memory mach-o file
634 ImageLoader* ImageLoaderMachO::instantiateFromMemory(const char* moduleName, const macho_header* mh, uint64_t len, const LinkContext& context)
635 {
636 bool compressed;
637 unsigned int segCount;
638 unsigned int libCount;
639 const linkedit_data_command* sigcmd;
640 const encryption_info_command* encryptCmd;
641 sniffLoadCommands(mh, moduleName, false, &compressed, &segCount, &libCount, context, &sigcmd, &encryptCmd);
642 // instantiate concrete class based on content of load commands
643 if ( compressed )
644 return ImageLoaderMachOCompressed::instantiateFromMemory(moduleName, mh, len, segCount, libCount, context);
645 else
646 #if SUPPORT_CLASSIC_MACHO
647 return ImageLoaderMachOClassic::instantiateFromMemory(moduleName, mh, len, segCount, libCount, context);
648 #else
649 throw "missing LC_DYLD_INFO load command";
650 #endif
651 }
652
653
654 int ImageLoaderMachO::crashIfInvalidCodeSignature()
655 {
656 // Now that segments are mapped in, try reading from first executable segment.
657 // If code signing is enabled the kernel will validate the code signature
658 // when paging in, and kill the process if invalid.
659 for(unsigned int i=0; i < fSegmentsCount; ++i) {
660 if ( (segFileOffset(i) == 0) && (segFileSize(i) != 0) ) {
661 // return read value to ensure compiler does not optimize away load
662 int* p = (int*)segActualLoadAddress(i);
663 return *p;
664 }
665 }
666 return 0;
667 }
668
669
670 void ImageLoaderMachO::parseLoadCmds(const LinkContext& context)
671 {
672 // now that segments are mapped in, get real fMachOData, fLinkEditBase, and fSlide
673 for(unsigned int i=0; i < fSegmentsCount; ++i) {
674 // set up pointer to __LINKEDIT segment
675 if ( strcmp(segName(i),"__LINKEDIT") == 0 ) {
676 if ( context.requireCodeSignature && (segFileOffset(i) > fCoveredCodeLength))
677 dyld::throwf("cannot load '%s' (segment outside of code signature)", this->getShortName());
678 fLinkEditBase = (uint8_t*)(segActualLoadAddress(i) - segFileOffset(i));
679 }
680 #if TEXT_RELOC_SUPPORT
681 // __TEXT segment always starts at beginning of file and contains mach_header and load commands
682 if ( segExecutable(i) ) {
683 if ( segHasRebaseFixUps(i) && (fSlide != 0) )
684 fTextSegmentRebases = true;
685 if ( segHasBindFixUps(i) )
686 fTextSegmentBinds = true;
687 }
688 #endif
689 #if __i386__
690 if ( segIsReadOnlyImport(i) )
691 fReadOnlyImportSegment = true;
692 #endif
693 // some segment always starts at beginning of file and contains mach_header and load commands
694 if ( (segFileOffset(i) == 0) && (segFileSize(i) != 0) ) {
695 fMachOData = (uint8_t*)(segActualLoadAddress(i));
696 }
697 }
698
699 // keep count of prebound images with weak exports
700 if ( this->participatesInCoalescing() ) {
701 ++fgImagesRequiringCoalescing;
702 fRegisteredAsRequiresCoalescing = true;
703 if ( this->hasCoalescedExports() )
704 ++fgImagesHasWeakDefinitions;
705 }
706
707 // keep count of images used in shared cache
708 if ( fInSharedCache )
709 ++fgImagesUsedFromSharedCache;
710
711 // walk load commands (mapped in at start of __TEXT segment)
712 const dyld_info_command* dyldInfo = NULL;
713 const macho_nlist* symbolTable = NULL;
714 const char* symbolTableStrings = NULL;
715 const struct load_command* firstUnknownCmd = NULL;
716 const struct version_min_command* minOSVersionCmd = NULL;
717 const dysymtab_command* dynSymbolTable = NULL;
718 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
719 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
720 const struct load_command* cmd = cmds;
721 for (uint32_t i = 0; i < cmd_count; ++i) {
722 switch (cmd->cmd) {
723 case LC_SYMTAB:
724 {
725 const struct symtab_command* symtab = (struct symtab_command*)cmd;
726 symbolTableStrings = (const char*)&fLinkEditBase[symtab->stroff];
727 symbolTable = (macho_nlist*)(&fLinkEditBase[symtab->symoff]);
728 }
729 break;
730 case LC_DYSYMTAB:
731 dynSymbolTable = (struct dysymtab_command*)cmd;
732 break;
733 case LC_SUB_UMBRELLA:
734 fHasSubUmbrella = true;
735 break;
736 case LC_SUB_FRAMEWORK:
737 fInUmbrella = true;
738 break;
739 case LC_SUB_LIBRARY:
740 fHasSubLibraries = true;
741 break;
742 case LC_ROUTINES_COMMAND:
743 fHasDashInit = true;
744 break;
745 case LC_DYLD_INFO:
746 case LC_DYLD_INFO_ONLY:
747 dyldInfo = (struct dyld_info_command*)cmd;
748 break;
749 case LC_SEGMENT_COMMAND:
750 {
751 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
752 const bool isTextSeg = (strcmp(seg->segname, "__TEXT") == 0);
753 #if __i386__ && __MAC_OS_X_VERSION_MIN_REQUIRED
754 const bool isObjCSeg = (strcmp(seg->segname, "__OBJC") == 0);
755 if ( isObjCSeg )
756 fNotifyObjC = true;
757 #else
758 const bool isDataSeg = (strncmp(seg->segname, "__DATA", 6) == 0);
759 #endif
760 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
761 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
762 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
763 const uint8_t type = sect->flags & SECTION_TYPE;
764 if ( type == S_MOD_INIT_FUNC_POINTERS )
765 fHasInitializers = true;
766 else if ( type == S_MOD_TERM_FUNC_POINTERS )
767 fHasTerminators = true;
768 else if ( type == S_DTRACE_DOF )
769 fHasDOFSections = true;
770 else if ( isTextSeg && (strcmp(sect->sectname, "__eh_frame") == 0) )
771 fEHFrameSectionOffset = (uint32_t)((uint8_t*)sect - fMachOData);
772 else if ( isTextSeg && (strcmp(sect->sectname, "__unwind_info") == 0) )
773 fUnwindInfoSectionOffset = (uint32_t)((uint8_t*)sect - fMachOData);
774
775 #if __i386__ && __MAC_OS_X_VERSION_MIN_REQUIRED
776 else if ( isObjCSeg ) {
777 if ( strcmp(sect->sectname, "__image_info") == 0 ) {
778 const uint32_t* imageInfo = (uint32_t*)(sect->addr + fSlide);
779 uint32_t flags = imageInfo[1];
780 if ( (flags & 4) && (((macho_header*)fMachOData)->filetype != MH_EXECUTE) )
781 dyld::throwf("cannot load '%s' because Objective-C garbage collection is not supported", getPath());
782 }
783 else if ( ((macho_header*)fMachOData)->filetype == MH_DYLIB ) {
784 fRetainForObjC = true;
785 }
786 }
787 #else
788 else if ( isDataSeg && (strncmp(sect->sectname, "__objc_imageinfo", 16) == 0) ) {
789 #if __MAC_OS_X_VERSION_MIN_REQUIRED
790 const uint32_t* imageInfo = (uint32_t*)(sect->addr + fSlide);
791 uint32_t flags = imageInfo[1];
792 if ( (flags & 4) && (((macho_header*)fMachOData)->filetype != MH_EXECUTE) )
793 dyld::throwf("cannot load '%s' because Objective-C garbage collection is not supported", getPath());
794 #endif
795 fNotifyObjC = true;
796 }
797 else if ( isDataSeg && (strncmp(sect->sectname, "__objc_", 7) == 0) && (((macho_header*)fMachOData)->filetype == MH_DYLIB) )
798 fRetainForObjC = true;
799 #endif
800 }
801 }
802 break;
803 case LC_TWOLEVEL_HINTS:
804 // no longer supported
805 break;
806 case LC_ID_DYLIB:
807 {
808 fDylibIDOffset = (uint32_t)((uint8_t*)cmd - fMachOData);
809 }
810 break;
811 case LC_RPATH:
812 case LC_LOAD_WEAK_DYLIB:
813 case LC_REEXPORT_DYLIB:
814 case LC_LOAD_UPWARD_DYLIB:
815 case LC_MAIN:
816 // do nothing, just prevent LC_REQ_DYLD exception from occuring
817 break;
818 case LC_VERSION_MIN_MACOSX:
819 case LC_VERSION_MIN_IPHONEOS:
820 case LC_VERSION_MIN_TVOS:
821 case LC_VERSION_MIN_WATCHOS:
822 minOSVersionCmd = (version_min_command*)cmd;
823 break;
824 default:
825 if ( (cmd->cmd & LC_REQ_DYLD) != 0 ) {
826 if ( firstUnknownCmd == NULL )
827 firstUnknownCmd = cmd;
828 }
829 break;
830 }
831 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
832 }
833 if ( firstUnknownCmd != NULL ) {
834 if ( minOSVersionCmd != NULL ) {
835 dyld::throwf("cannot load '%s' because it was built for OS version %u.%u (load command 0x%08X is unknown)",
836 this->getShortName(),
837 minOSVersionCmd->version >> 16, ((minOSVersionCmd->version >> 8) & 0xff),
838 firstUnknownCmd->cmd);
839 }
840 else {
841 dyld::throwf("cannot load '%s' (load command 0x%08X is unknown)", this->getShortName(), firstUnknownCmd->cmd);
842 }
843 }
844
845
846 if ( dyldInfo != NULL )
847 this->setDyldInfo(dyldInfo);
848 if ( symbolTable != NULL)
849 this->setSymbolTableInfo(symbolTable, symbolTableStrings, dynSymbolTable);
850
851 }
852
853 // don't do this work in destructor because we need object to be full subclass
854 // for UnmapSegments() to work
855 void ImageLoaderMachO::destroy()
856 {
857 // update count of images with weak exports
858 if ( fRegisteredAsRequiresCoalescing ) {
859 --fgImagesRequiringCoalescing;
860 if ( this->hasCoalescedExports() )
861 --fgImagesHasWeakDefinitions;
862 }
863
864 // keep count of images used in shared cache
865 if ( fInSharedCache )
866 --fgImagesUsedFromSharedCache;
867
868 // unmap image when done
869 UnmapSegments();
870 }
871
872
873 unsigned int ImageLoaderMachO::segmentCount() const
874 {
875 return fSegmentsCount;
876 }
877
878
879 const macho_segment_command* ImageLoaderMachO::segLoadCommand(unsigned int segIndex) const
880 {
881 uint32_t* lcOffsets = this->segmentCommandOffsets();
882 uint32_t lcOffset = lcOffsets[segIndex];
883 return (macho_segment_command*)(&fMachOData[lcOffset]);
884 }
885
886 const char* ImageLoaderMachO::segName(unsigned int segIndex) const
887 {
888 return segLoadCommand(segIndex)->segname;
889 }
890
891
892 uintptr_t ImageLoaderMachO::segSize(unsigned int segIndex) const
893 {
894 return segLoadCommand(segIndex)->vmsize;
895 }
896
897
898 uintptr_t ImageLoaderMachO::segFileSize(unsigned int segIndex) const
899 {
900 return segLoadCommand(segIndex)->filesize;
901 }
902
903
904 bool ImageLoaderMachO::segHasTrailingZeroFill(unsigned int segIndex)
905 {
906 return ( segWriteable(segIndex) && (segSize(segIndex) > segFileSize(segIndex)) );
907 }
908
909
910 uintptr_t ImageLoaderMachO::segFileOffset(unsigned int segIndex) const
911 {
912 return segLoadCommand(segIndex)->fileoff;
913 }
914
915
916 bool ImageLoaderMachO::segReadable(unsigned int segIndex) const
917 {
918 return ( (segLoadCommand(segIndex)->initprot & VM_PROT_READ) != 0);
919 }
920
921
922 bool ImageLoaderMachO::segWriteable(unsigned int segIndex) const
923 {
924 return ( (segLoadCommand(segIndex)->initprot & VM_PROT_WRITE) != 0);
925 }
926
927
928 bool ImageLoaderMachO::segExecutable(unsigned int segIndex) const
929 {
930 return ( (segLoadCommand(segIndex)->initprot & VM_PROT_EXECUTE) != 0);
931 }
932
933
934 bool ImageLoaderMachO::segUnaccessible(unsigned int segIndex) const
935 {
936 return (segLoadCommand(segIndex)->initprot == 0);
937 }
938
939 bool ImageLoaderMachO::segHasPreferredLoadAddress(unsigned int segIndex) const
940 {
941 return (segLoadCommand(segIndex)->vmaddr != 0);
942 }
943
944 uintptr_t ImageLoaderMachO::segPreferredLoadAddress(unsigned int segIndex) const
945 {
946 return segLoadCommand(segIndex)->vmaddr;
947 }
948
949 uintptr_t ImageLoaderMachO::segActualLoadAddress(unsigned int segIndex) const
950 {
951 return segLoadCommand(segIndex)->vmaddr + fSlide;
952 }
953
954
955 uintptr_t ImageLoaderMachO::segActualEndAddress(unsigned int segIndex) const
956 {
957 return segActualLoadAddress(segIndex) + segSize(segIndex);
958 }
959
960 bool ImageLoaderMachO::segHasRebaseFixUps(unsigned int segIndex) const
961 {
962 #if TEXT_RELOC_SUPPORT
963 // scan sections for fix-up bit
964 const macho_segment_command* segCmd = segLoadCommand(segIndex);
965 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)segCmd + sizeof(struct macho_segment_command));
966 const struct macho_section* const sectionsEnd = &sectionsStart[segCmd->nsects];
967 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
968 if ( (sect->flags & S_ATTR_LOC_RELOC) != 0 )
969 return true;
970 }
971 #endif
972 return false;
973 }
974
975 bool ImageLoaderMachO::segHasBindFixUps(unsigned int segIndex) const
976 {
977 #if TEXT_RELOC_SUPPORT
978 // scan sections for fix-up bit
979 const macho_segment_command* segCmd = segLoadCommand(segIndex);
980 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)segCmd + sizeof(struct macho_segment_command));
981 const struct macho_section* const sectionsEnd = &sectionsStart[segCmd->nsects];
982 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
983 if ( (sect->flags & S_ATTR_EXT_RELOC) != 0 )
984 return true;
985 }
986 #endif
987 return false;
988 }
989
990 #if __i386__
991 bool ImageLoaderMachO::segIsReadOnlyImport(unsigned int segIndex) const
992 {
993 const macho_segment_command* segCmd = segLoadCommand(segIndex);
994 return ( (segCmd->initprot & VM_PROT_EXECUTE)
995 && ((segCmd->initprot & VM_PROT_WRITE) == 0)
996 && (strcmp(segCmd->segname, "__IMPORT") == 0) );
997 }
998 #endif
999
1000
1001 void ImageLoaderMachO::UnmapSegments()
1002 {
1003 // usually unmap image when done
1004 if ( ! this->leaveMapped() && (this->getState() >= dyld_image_state_mapped) ) {
1005 // unmap TEXT segment last because it contains load command being inspected
1006 unsigned int textSegmentIndex = 0;
1007 for(unsigned int i=0; i < fSegmentsCount; ++i) {
1008 //dyld::log("unmap %s at 0x%08lX\n", seg->getName(), seg->getActualLoadAddress(this));
1009 if ( (segFileOffset(i) == 0) && (segFileSize(i) != 0) ) {
1010 textSegmentIndex = i;
1011 }
1012 else {
1013 // update stats
1014 --ImageLoader::fgTotalSegmentsMapped;
1015 ImageLoader::fgTotalBytesMapped -= segSize(i);
1016 munmap((void*)segActualLoadAddress(i), segSize(i));
1017 }
1018 }
1019 // now unmap TEXT
1020 --ImageLoader::fgTotalSegmentsMapped;
1021 ImageLoader::fgTotalBytesMapped -= segSize(textSegmentIndex);
1022 munmap((void*)segActualLoadAddress(textSegmentIndex), segSize(textSegmentIndex));
1023 }
1024 }
1025
1026
1027 // prefetch __DATA/__OBJC pages during launch, but not for dynamically loaded code
1028 void ImageLoaderMachO::preFetchDATA(int fd, uint64_t offsetInFat, const LinkContext& context)
1029 {
1030 if ( context.linkingMainExecutable ) {
1031 for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
1032 if ( segWriteable(i) && (segFileSize(i) > 0) ) {
1033 // prefetch writable segment that have mmap'ed regions
1034 radvisory advice;
1035 advice.ra_offset = offsetInFat + segFileOffset(i);
1036 advice.ra_count = (int)segFileSize(i);
1037 // limit prefetch to 1MB (256 pages)
1038 if ( advice.ra_count > 1024*1024 )
1039 advice.ra_count = 1024*1024;
1040 // don't prefetch single pages, let them fault in
1041 fgTotalBytesPreFetched += advice.ra_count;
1042 fcntl(fd, F_RDADVISE, &advice);
1043 if ( context.verboseMapping ) {
1044 dyld::log("%18s prefetching 0x%0lX -> 0x%0lX\n",
1045 segName(i), segActualLoadAddress(i), segActualLoadAddress(i)+advice.ra_count-1);
1046 }
1047 }
1048 }
1049 }
1050 }
1051
1052
1053 bool ImageLoaderMachO::segmentsMustSlideTogether() const
1054 {
1055 return true;
1056 }
1057
1058 bool ImageLoaderMachO::segmentsCanSlide() const
1059 {
1060 return (this->isDylib() || this->isBundle() || this->isPositionIndependentExecutable());
1061 }
1062
1063 bool ImageLoaderMachO::isBundle() const
1064 {
1065 const macho_header* mh = (macho_header*)fMachOData;
1066 return ( mh->filetype == MH_BUNDLE );
1067 }
1068
1069 bool ImageLoaderMachO::isDylib() const
1070 {
1071 const macho_header* mh = (macho_header*)fMachOData;
1072 return ( mh->filetype == MH_DYLIB );
1073 }
1074
1075 bool ImageLoaderMachO::isExecutable() const
1076 {
1077 const macho_header* mh = (macho_header*)fMachOData;
1078 return ( mh->filetype == MH_EXECUTE );
1079 }
1080
1081 bool ImageLoaderMachO::isPositionIndependentExecutable() const
1082 {
1083 const macho_header* mh = (macho_header*)fMachOData;
1084 return ( (mh->filetype == MH_EXECUTE) && ((mh->flags & MH_PIE) != 0) );
1085 }
1086
1087
1088 bool ImageLoaderMachO::forceFlat() const
1089 {
1090 const macho_header* mh = (macho_header*)fMachOData;
1091 return ( (mh->flags & MH_FORCE_FLAT) != 0 );
1092 }
1093
1094 bool ImageLoaderMachO::usesTwoLevelNameSpace() const
1095 {
1096 const macho_header* mh = (macho_header*)fMachOData;
1097 return ( (mh->flags & MH_TWOLEVEL) != 0 );
1098 }
1099
1100 bool ImageLoaderMachO::isPrebindable() const
1101 {
1102 const macho_header* mh = (macho_header*)fMachOData;
1103 return ( (mh->flags & MH_PREBOUND) != 0 );
1104 }
1105
1106 bool ImageLoaderMachO::hasCoalescedExports() const
1107 {
1108 const macho_header* mh = (macho_header*)fMachOData;
1109 return ( (mh->flags & MH_WEAK_DEFINES) != 0 );
1110 }
1111
1112 bool ImageLoaderMachO::hasReferencesToWeakSymbols() const
1113 {
1114 const macho_header* mh = (macho_header*)fMachOData;
1115 return ( (mh->flags & MH_BINDS_TO_WEAK) != 0 );
1116 }
1117
1118 bool ImageLoaderMachO::participatesInCoalescing() const
1119 {
1120 const macho_header* mh = (macho_header*)fMachOData;
1121 // if image is loaded with RTLD_LOCAL, then its symbols' visibility
1122 // is reduced and it can't coalesce with other images
1123 if ( this->hasHiddenExports() )
1124 return false;
1125 return ( (mh->flags & (MH_WEAK_DEFINES|MH_BINDS_TO_WEAK)) != 0 );
1126 }
1127
1128
1129
1130 void ImageLoaderMachO::setSlide(intptr_t slide)
1131 {
1132 fSlide = slide;
1133 }
1134
1135 void ImageLoaderMachO::loadCodeSignature(const struct linkedit_data_command* codeSigCmd, int fd, uint64_t offsetInFatFile, const LinkContext& context)
1136 {
1137 // if dylib being loaded has no code signature load command
1138 if ( codeSigCmd == NULL) {
1139 if (context.requireCodeSignature ) {
1140 // if we require dylibs to be codesigned there needs to be a signature.
1141 dyld::throwf("required code signature missing for '%s'\n", this->getPath());
1142 } else {
1143 disableCoverageCheck();
1144 }
1145 }
1146 else {
1147 #if __MAC_OS_X_VERSION_MIN_REQUIRED
1148 // <rdar://problem/13622786> ignore code signatures in binaries built with pre-10.9 tools
1149 if ( this->sdkVersion() < DYLD_MACOSX_VERSION_10_9 ) {
1150 return;
1151 }
1152 #endif
1153 fsignatures_t siginfo;
1154 siginfo.fs_file_start=offsetInFatFile; // start of mach-o slice in fat file
1155 siginfo.fs_blob_start=(void*)(long)(codeSigCmd->dataoff); // start of CD in mach-o file
1156 siginfo.fs_blob_size=codeSigCmd->datasize; // size of CD
1157 int result = fcntl(fd, F_ADDFILESIGS_RETURN, &siginfo);
1158
1159 #if TARGET_IPHONE_SIMULATOR
1160 // rdar://problem/18759224> check range covered by the code directory after loading
1161 // Attempt to fallback only if we are in the simulator
1162
1163 if ( result == -1 ) {
1164 result = fcntl(fd, F_ADDFILESIGS, &siginfo);
1165 siginfo.fs_file_start = codeSigCmd->dataoff;
1166 }
1167 #endif
1168
1169 if ( result == -1 ) {
1170 if ( (errno == EPERM) || (errno == EBADEXEC) )
1171 dyld::throwf("code signature invalid for '%s'\n", this->getPath());
1172 if ( context.verboseCodeSignatures )
1173 dyld::log("dyld: Failed registering code signature for %s, errno=%d\n", this->getPath(), errno);
1174 siginfo.fs_file_start = UINT64_MAX;
1175 } else if ( context.verboseCodeSignatures ) {
1176 dyld::log("dyld: Registered code signature for %s\n", this->getPath());
1177 }
1178 fCoveredCodeLength = siginfo.fs_file_start;
1179
1180 #if __MAC_OS_X_VERSION_MIN_REQUIRED
1181 if ( context.processUsingLibraryValidation ) {
1182 fchecklv checkInfo;
1183 char messageBuffer[512];
1184 messageBuffer[0] = '\0';
1185 checkInfo.lv_file_start = offsetInFatFile;
1186 checkInfo.lv_error_message_size = sizeof(messageBuffer);
1187 checkInfo.lv_error_message = messageBuffer;
1188 int res = fcntl(fd, F_CHECK_LV, &checkInfo);
1189 if ( res == -1 ) {
1190 dyld::throwf("code signature in (%s) not valid for use in process using Library Validation: %s", this->getPath(), messageBuffer);
1191 }
1192 }
1193 #endif
1194 }
1195 }
1196
1197 void ImageLoaderMachO::validateFirstPages(const struct linkedit_data_command* codeSigCmd, int fd, const uint8_t *fileData, size_t lenFileData, off_t offsetInFat, const LinkContext& context)
1198 {
1199 #if __MAC_OS_X_VERSION_MIN_REQUIRED
1200 // rdar://problem/21839703> 15A226d: dyld crashes in mageLoaderMachO::validateFirstPages during dlopen() after encountering an mmap failure
1201 // We need to ignore older code signatures because they will be bad.
1202 if ( this->sdkVersion() < DYLD_MACOSX_VERSION_10_9 ) {
1203 return;
1204 }
1205 #endif
1206 if (codeSigCmd != NULL) {
1207 void *fdata = xmmap(NULL, lenFileData, PROT_READ | PROT_EXEC, MAP_SHARED, fd, offsetInFat);
1208 if ( fdata == MAP_FAILED ) {
1209 #if __MAC_OS_X_VERSION_MIN_REQUIRED
1210 if ( context.processUsingLibraryValidation ) {
1211 dyld::throwf("cannot load image with wrong team ID in process using Library Validation");
1212 }
1213 else
1214 #endif
1215 {
1216 int errnoCopy = errno;
1217 if ( errnoCopy == EPERM ) {
1218 if ( dyld::sandboxBlockedMmap(getPath()) )
1219 dyld::throwf("file system sandbox blocked mmap() of '%s'", getPath());
1220 else
1221 dyld::throwf("code signing blocked mmap() of '%s'", getPath());
1222 }
1223 else
1224 dyld::throwf("mmap() errno=%d validating first page of '%s'", errnoCopy, getPath());
1225 }
1226 }
1227 if ( memcmp(fdata, fileData, lenFileData) != 0 )
1228 dyld::throwf("mmap() page compare failed for '%s'", getPath());
1229 munmap(fdata, lenFileData);
1230 }
1231 }
1232
1233
1234 const char* ImageLoaderMachO::getInstallPath() const
1235 {
1236 if ( fDylibIDOffset != 0 ) {
1237 const dylib_command* dylibID = (dylib_command*)(&fMachOData[fDylibIDOffset]);
1238 return (char*)dylibID + dylibID->dylib.name.offset;
1239 }
1240 return NULL;
1241 }
1242
1243 void ImageLoaderMachO::registerInterposing()
1244 {
1245 // mach-o files advertise interposing by having a __DATA __interpose section
1246 struct InterposeData { uintptr_t replacement; uintptr_t replacee; };
1247 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1248 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1249 const struct load_command* cmd = cmds;
1250 for (uint32_t i = 0; i < cmd_count; ++i) {
1251 switch (cmd->cmd) {
1252 case LC_SEGMENT_COMMAND:
1253 {
1254 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
1255 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
1256 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
1257 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
1258 if ( ((sect->flags & SECTION_TYPE) == S_INTERPOSING) || ((strcmp(sect->sectname, "__interpose") == 0) && (strcmp(seg->segname, "__DATA") == 0)) ) {
1259 // <rdar://problem/23929217> Ensure section is within segment
1260 if ( (sect->addr < seg->vmaddr) || (sect->addr+sect->size > seg->vmaddr+seg->vmsize) || (sect->addr+sect->size < sect->addr) )
1261 dyld::throwf("interpose section has malformed address range for %s\n", this->getPath());
1262 const InterposeData* interposeArray = (InterposeData*)(sect->addr + fSlide);
1263 const size_t count = sect->size / sizeof(InterposeData);
1264 for (size_t j=0; j < count; ++j) {
1265 ImageLoader::InterposeTuple tuple;
1266 tuple.replacement = interposeArray[j].replacement;
1267 tuple.neverImage = this;
1268 tuple.onlyImage = NULL;
1269 tuple.replacee = interposeArray[j].replacee;
1270 // <rdar://problem/25686570> ignore interposing on a weak function that does not exist
1271 if ( tuple.replacee == 0 )
1272 continue;
1273 // <rdar://problem/7937695> verify that replacement is in this image
1274 if ( this->containsAddress((void*)tuple.replacement) ) {
1275 // chain to any existing interpositions
1276 for (std::vector<InterposeTuple>::iterator it=fgInterposingTuples.begin(); it != fgInterposingTuples.end(); it++) {
1277 if ( it->replacee == tuple.replacee ) {
1278 tuple.replacee = it->replacement;
1279 }
1280 }
1281 ImageLoader::fgInterposingTuples.push_back(tuple);
1282 }
1283 }
1284 }
1285 }
1286 }
1287 break;
1288 }
1289 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1290 }
1291 }
1292
1293 uint32_t ImageLoaderMachO::sdkVersion(const mach_header* mh)
1294 {
1295 const uint32_t cmd_count = mh->ncmds;
1296 const struct load_command* const cmds = (struct load_command*)(((char*)mh) + sizeof(macho_header));
1297 const struct load_command* cmd = cmds;
1298 const struct version_min_command* versCmd;
1299 const struct build_version_command* buildVersCmd;
1300 for (uint32_t i = 0; i < cmd_count; ++i) {
1301 switch ( cmd->cmd ) {
1302 case LC_VERSION_MIN_MACOSX:
1303 case LC_VERSION_MIN_IPHONEOS:
1304 case LC_VERSION_MIN_TVOS:
1305 case LC_VERSION_MIN_WATCHOS:
1306 versCmd = (version_min_command*)cmd;
1307 return versCmd->sdk;
1308 case LC_BUILD_VERSION:
1309 buildVersCmd = (build_version_command*)cmd;
1310 return buildVersCmd->sdk;
1311 }
1312 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1313 }
1314 return 0;
1315 }
1316
1317 uint32_t ImageLoaderMachO::sdkVersion() const
1318 {
1319 return ImageLoaderMachO::sdkVersion(machHeader());
1320 }
1321
1322 uint32_t ImageLoaderMachO::minOSVersion(const mach_header* mh)
1323 {
1324 const uint32_t cmd_count = mh->ncmds;
1325 const struct load_command* const cmds = (struct load_command*)(((char*)mh) + sizeof(macho_header));
1326 const struct load_command* cmd = cmds;
1327 const struct version_min_command* versCmd;
1328 const struct build_version_command* buildVersCmd;
1329 for (uint32_t i = 0; i < cmd_count; ++i) {
1330 switch ( cmd->cmd ) {
1331 case LC_VERSION_MIN_MACOSX:
1332 case LC_VERSION_MIN_IPHONEOS:
1333 case LC_VERSION_MIN_TVOS:
1334 case LC_VERSION_MIN_WATCHOS:
1335 versCmd = (version_min_command*)cmd;
1336 return versCmd->version;
1337 case LC_BUILD_VERSION:
1338 buildVersCmd = (build_version_command*)cmd;
1339 return buildVersCmd->minos;
1340 }
1341 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1342 }
1343 return 0;
1344 }
1345
1346 uint32_t ImageLoaderMachO::minOSVersion() const
1347 {
1348 return ImageLoaderMachO::minOSVersion(machHeader());
1349 }
1350
1351
1352 void* ImageLoaderMachO::getThreadPC() const
1353 {
1354 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1355 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1356 const struct load_command* cmd = cmds;
1357 for (uint32_t i = 0; i < cmd_count; ++i) {
1358 if ( cmd->cmd == LC_MAIN ) {
1359 entry_point_command* mainCmd = (entry_point_command*)cmd;
1360 void* entry = (void*)(mainCmd->entryoff + (char*)fMachOData);
1361 // <rdar://problem/8543820&9228031> verify entry point is in image
1362 if ( this->containsAddress(entry) )
1363 return entry;
1364 else
1365 throw "LC_MAIN entryoff is out of range";
1366 }
1367 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1368 }
1369 return NULL;
1370 }
1371
1372
1373 void* ImageLoaderMachO::getMain() const
1374 {
1375 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1376 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1377 const struct load_command* cmd = cmds;
1378 for (uint32_t i = 0; i < cmd_count; ++i) {
1379 switch (cmd->cmd) {
1380 case LC_UNIXTHREAD:
1381 {
1382 #if __i386__
1383 const i386_thread_state_t* registers = (i386_thread_state_t*)(((char*)cmd) + 16);
1384 void* entry = (void*)(registers->eip + fSlide);
1385 #elif __x86_64__
1386 const x86_thread_state64_t* registers = (x86_thread_state64_t*)(((char*)cmd) + 16);
1387 void* entry = (void*)(registers->rip + fSlide);
1388 #elif __arm__
1389 const arm_thread_state_t* registers = (arm_thread_state_t*)(((char*)cmd) + 16);
1390 void* entry = (void*)(registers->__pc + fSlide);
1391 #elif __arm64__
1392 const arm_thread_state64_t* registers = (arm_thread_state64_t*)(((char*)cmd) + 16);
1393 void* entry = (void*)(registers->__pc + fSlide);
1394 #else
1395 #warning need processor specific code
1396 #endif
1397 // <rdar://problem/8543820&9228031> verify entry point is in image
1398 if ( this->containsAddress(entry) ) {
1399 return entry;
1400 }
1401 }
1402 break;
1403 }
1404 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1405 }
1406 throw "no valid entry point";
1407 }
1408
1409 bool ImageLoaderMachO::needsAddedLibSystemDepency(unsigned int libCount, const macho_header* mh)
1410 {
1411 // <rdar://problem/6357561> ensure that every image depends on something which depends on libSystem
1412 if ( libCount > 1 )
1413 return false;
1414
1415 // <rdar://problem/6409800> dyld implicit-libSystem breaks valgrind
1416 if ( mh->filetype == MH_EXECUTE )
1417 return false;
1418
1419 bool isNonOSdylib = false;
1420 const uint32_t cmd_count = mh->ncmds;
1421 const struct load_command* const cmds = (struct load_command*)((uint8_t*)mh+sizeof(macho_header));
1422 const struct load_command* cmd = cmds;
1423 for (uint32_t i = 0; i < cmd_count; ++i) {
1424 switch (cmd->cmd) {
1425 case LC_LOAD_DYLIB:
1426 case LC_LOAD_WEAK_DYLIB:
1427 case LC_REEXPORT_DYLIB:
1428 case LC_LOAD_UPWARD_DYLIB:
1429 return false;
1430 case LC_ID_DYLIB:
1431 {
1432 const dylib_command* dylibID = (dylib_command*)cmd;
1433 const char* installPath = (char*)cmd + dylibID->dylib.name.offset;
1434 // It is OK for OS dylibs (libSystem or libmath or Rosetta shims) to have no dependents
1435 // but all other dylibs must depend on libSystem for initialization to initialize libSystem first
1436 // <rdar://problem/6497528> rosetta circular dependency spew
1437 isNonOSdylib = ( (strncmp(installPath, "/usr/lib/", 9) != 0) && (strncmp(installPath, "/usr/libexec/oah/Shims", 9) != 0) );
1438 }
1439 break;
1440 }
1441 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1442 }
1443 return isNonOSdylib;
1444 }
1445
1446
1447 void ImageLoaderMachO::doGetDependentLibraries(DependentLibraryInfo libs[])
1448 {
1449 if ( needsAddedLibSystemDepency(libraryCount(), (macho_header*)fMachOData) ) {
1450 DependentLibraryInfo* lib = &libs[0];
1451 lib->name = LIBSYSTEM_DYLIB_PATH;
1452 lib->info.checksum = 0;
1453 lib->info.minVersion = 0;
1454 lib->info.maxVersion = 0;
1455 lib->required = false;
1456 lib->reExported = false;
1457 lib->upward = false;
1458 }
1459 else {
1460 uint32_t index = 0;
1461 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1462 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1463 const struct load_command* cmd = cmds;
1464 for (uint32_t i = 0; i < cmd_count; ++i) {
1465 switch (cmd->cmd) {
1466 case LC_LOAD_DYLIB:
1467 case LC_LOAD_WEAK_DYLIB:
1468 case LC_REEXPORT_DYLIB:
1469 case LC_LOAD_UPWARD_DYLIB:
1470 {
1471 const struct dylib_command* dylib = (struct dylib_command*)cmd;
1472 DependentLibraryInfo* lib = &libs[index++];
1473 lib->name = (char*)cmd + dylib->dylib.name.offset;
1474 //lib->name = strdup((char*)cmd + dylib->dylib.name.offset);
1475 lib->info.checksum = dylib->dylib.timestamp;
1476 lib->info.minVersion = dylib->dylib.compatibility_version;
1477 lib->info.maxVersion = dylib->dylib.current_version;
1478 lib->required = (cmd->cmd != LC_LOAD_WEAK_DYLIB);
1479 lib->reExported = (cmd->cmd == LC_REEXPORT_DYLIB);
1480 lib->upward = (cmd->cmd == LC_LOAD_UPWARD_DYLIB);
1481 }
1482 break;
1483 }
1484 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1485 }
1486 }
1487 }
1488
1489 ImageLoader::LibraryInfo ImageLoaderMachO::doGetLibraryInfo(const LibraryInfo&)
1490 {
1491 LibraryInfo info;
1492 if ( fDylibIDOffset != 0 ) {
1493 const dylib_command* dylibID = (dylib_command*)(&fMachOData[fDylibIDOffset]);
1494 info.minVersion = dylibID->dylib.compatibility_version;
1495 info.maxVersion = dylibID->dylib.current_version;
1496 info.checksum = dylibID->dylib.timestamp;
1497 }
1498 else {
1499 info.minVersion = 0;
1500 info.maxVersion = 0;
1501 info.checksum = 0;
1502 }
1503 return info;
1504 }
1505
1506 void ImageLoaderMachO::getRPaths(const LinkContext& context, std::vector<const char*>& paths) const
1507 {
1508 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1509 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1510 const struct load_command* cmd = cmds;
1511 for (uint32_t i = 0; i < cmd_count; ++i) {
1512 switch (cmd->cmd) {
1513 case LC_RPATH:
1514 const char* pathToAdd = NULL;
1515 const char* path = (char*)cmd + ((struct rpath_command*)cmd)->path.offset;
1516 if ( (strncmp(path, "@loader_path", 12) == 0) && ((path[12] == '/') || (path[12] == '\0')) ) {
1517 #if __MAC_OS_X_VERSION_MIN_REQUIRED
1518 if ( context.processIsRestricted && (context.mainExecutable == this) ) {
1519 dyld::warn("LC_RPATH %s in %s being ignored in restricted program because of @loader_path\n", path, this->getPath());
1520 break;
1521 }
1522 #endif
1523 char resolvedPath[PATH_MAX];
1524 if ( realpath(this->getPath(), resolvedPath) != NULL ) {
1525 char newRealPath[strlen(resolvedPath) + strlen(path)];
1526 strcpy(newRealPath, resolvedPath);
1527 char* addPoint = strrchr(newRealPath,'/');
1528 if ( addPoint != NULL ) {
1529 strcpy(addPoint, &path[12]);
1530 pathToAdd = strdup(newRealPath);
1531 }
1532 }
1533 }
1534 else if ( (strncmp(path, "@executable_path", 16) == 0) && ((path[16] == '/') || (path[16] == '\0')) ) {
1535 #if __MAC_OS_X_VERSION_MIN_REQUIRED
1536 if ( context.processIsRestricted ) {
1537 dyld::warn("LC_RPATH %s in %s being ignored in restricted program because of @executable_path\n", path, this->getPath());
1538 break;
1539 }
1540 #endif
1541 char resolvedPath[PATH_MAX];
1542 if ( realpath(context.mainExecutable->getPath(), resolvedPath) != NULL ) {
1543 char newRealPath[strlen(resolvedPath) + strlen(path)];
1544 strcpy(newRealPath, resolvedPath);
1545 char* addPoint = strrchr(newRealPath,'/');
1546 if ( addPoint != NULL ) {
1547 strcpy(addPoint, &path[16]);
1548 pathToAdd = strdup(newRealPath);
1549 }
1550 }
1551 }
1552 #if __MAC_OS_X_VERSION_MIN_REQUIRED
1553 else if ( (path[0] != '/') && context.processIsRestricted ) {
1554 dyld::warn("LC_RPATH %s in %s being ignored in restricted program because it is a relative path\n", path, this->getPath());
1555 break;
1556 }
1557 #endif
1558 #if SUPPORT_ROOT_PATH
1559 else if ( (path[0] == '/') && (context.rootPaths != NULL) ) {
1560 // <rdar://problem/5869973> DYLD_ROOT_PATH should apply to LC_RPATH rpaths
1561 // DYLD_ROOT_PATH can be a list of paths, but at this point we can only support one, so use first combination that exists
1562 bool found = false;
1563 for(const char** rp = context.rootPaths; *rp != NULL; ++rp) {
1564 char newPath[PATH_MAX];
1565 strlcpy(newPath, *rp, PATH_MAX);
1566 strlcat(newPath, path, PATH_MAX);
1567 struct stat stat_buf;
1568 if ( stat(newPath, &stat_buf) != -1 ) {
1569 //dyld::log("combined DYLD_ROOT_PATH and LC_RPATH: %s\n", newPath);
1570 pathToAdd = strdup(newPath);
1571 found = true;
1572 break;
1573 }
1574 }
1575 if ( ! found ) {
1576 // make copy so that all elements of 'paths' can be freed
1577 pathToAdd = strdup(path);
1578 }
1579 }
1580 #endif
1581 else {
1582 // make copy so that all elements of 'paths' can be freed
1583 pathToAdd = strdup(path);
1584 }
1585 if ( pathToAdd != NULL )
1586 paths.push_back(pathToAdd);
1587 break;
1588 }
1589 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1590 }
1591 }
1592
1593
1594 bool ImageLoaderMachO::getUUID(uuid_t uuid) const
1595 {
1596 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1597 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1598 const struct load_command* cmd = cmds;
1599 for (uint32_t i = 0; i < cmd_count; ++i) {
1600 switch (cmd->cmd) {
1601 case LC_UUID:
1602 uuid_command* uc = (uuid_command*)cmd;
1603 memcpy(uuid, uc->uuid, 16);
1604 return true;
1605 }
1606 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1607 }
1608 bzero(uuid, 16);
1609 return false;
1610 }
1611
1612 void ImageLoaderMachO::doRebase(const LinkContext& context)
1613 {
1614 // <rdar://problem/25329861> Delay calling setNeverUnload() until we know this is not for dlopen_preflight()
1615 if ( fRetainForObjC )
1616 this->setNeverUnload();
1617
1618 // if prebound and loaded at prebound address, then no need to rebase
1619 if ( this->usablePrebinding(context) ) {
1620 // skip rebasing because prebinding is valid
1621 ++fgImagesWithUsedPrebinding; // bump totals for statistics
1622 return;
1623 }
1624
1625 // print why prebinding was not used
1626 if ( context.verbosePrebinding ) {
1627 if ( !this->isPrebindable() ) {
1628 dyld::log("dyld: image not prebound, so could not use prebinding in %s\n", this->getPath());
1629 }
1630 else if ( fSlide != 0 ) {
1631 dyld::log("dyld: image slid, so could not use prebinding in %s\n", this->getPath());
1632 }
1633 else if ( !this->allDependentLibrariesAsWhenPreBound() ) {
1634 dyld::log("dyld: dependent libraries changed, so could not use prebinding in %s\n", this->getPath());
1635 }
1636 else if ( !this->usesTwoLevelNameSpace() ){
1637 dyld::log("dyld: image uses flat-namespace so, parts of prebinding ignored %s\n", this->getPath());
1638 }
1639 else {
1640 dyld::log("dyld: environment variable disabled use of prebinding in %s\n", this->getPath());
1641 }
1642 }
1643
1644 //dyld::log("slide=0x%08lX for %s\n", slide, this->getPath());
1645
1646 #if PREBOUND_IMAGE_SUPPORT
1647 // if prebound and we got here, then prebinding is not valid, so reset all lazy pointers
1648 // if this image is in the shared cache, do not reset, they will be bound in doBind()
1649 if ( this->isPrebindable() && !fInSharedCache )
1650 this->resetPreboundLazyPointers(context);
1651 #endif
1652
1653 // if loaded at preferred address, no rebasing necessary
1654 if ( this->fSlide == 0 )
1655 return;
1656
1657 #if TEXT_RELOC_SUPPORT
1658 // if there are __TEXT fixups, temporarily make __TEXT writable
1659 if ( fTextSegmentRebases )
1660 this->makeTextSegmentWritable(context, true);
1661 #endif
1662
1663 // do actual rebasing
1664 this->rebase(context, fSlide);
1665
1666 #if TEXT_RELOC_SUPPORT
1667 // if there were __TEXT fixups, restore write protection
1668 if ( fTextSegmentRebases )
1669 this->makeTextSegmentWritable(context, false);
1670
1671 #endif
1672 }
1673
1674 #if TEXT_RELOC_SUPPORT
1675 void ImageLoaderMachO::makeTextSegmentWritable(const LinkContext& context, bool writeable)
1676 {
1677 for(unsigned int i=0; i < fSegmentsCount; ++i) {
1678 if ( segExecutable(i) ) {
1679 if ( writeable ) {
1680 segMakeWritable(i, context);
1681 }
1682 else {
1683 #if !__i386__ && !__x86_64__
1684 // some processors require range to be invalidated before it is made executable
1685 sys_icache_invalidate((void*)segActualLoadAddress(i), segSize(textSegmentIndex));
1686 #endif
1687 segProtect(i, context);
1688 }
1689 }
1690 }
1691
1692 }
1693 #endif
1694
1695 const ImageLoader::Symbol* ImageLoaderMachO::findExportedSymbol(const char* name, bool searchReExports, const char* thisPath, const ImageLoader** foundIn) const
1696 {
1697 // look in this image first
1698 const ImageLoader::Symbol* result = this->findShallowExportedSymbol(name, foundIn);
1699 if ( result != NULL )
1700 return result;
1701
1702 if ( searchReExports ) {
1703 for(unsigned int i=0; i < libraryCount(); ++i){
1704 if ( libReExported(i) ) {
1705 ImageLoader* image = libImage(i);
1706 if ( image != NULL ) {
1707 const char* reExPath = libPath(i);
1708 result = image->findExportedSymbol(name, searchReExports, reExPath, foundIn);
1709 if ( result != NULL )
1710 return result;
1711 }
1712 }
1713 }
1714 }
1715
1716
1717 return NULL;
1718 }
1719
1720
1721
1722 uintptr_t ImageLoaderMachO::getExportedSymbolAddress(const Symbol* sym, const LinkContext& context,
1723 const ImageLoader* requestor, bool runResolver, const char* symbolName) const
1724 {
1725 return this->getSymbolAddress(sym, requestor, context, runResolver);
1726 }
1727
1728 uintptr_t ImageLoaderMachO::getSymbolAddress(const Symbol* sym, const ImageLoader* requestor,
1729 const LinkContext& context, bool runResolver) const
1730 {
1731 uintptr_t result = exportedSymbolAddress(context, sym, requestor, runResolver);
1732 // check for interposing overrides
1733 result = interposedAddress(context, result, requestor);
1734 return result;
1735 }
1736
1737 ImageLoader::DefinitionFlags ImageLoaderMachO::getExportedSymbolInfo(const Symbol* sym) const
1738 {
1739 if ( exportedSymbolIsWeakDefintion(sym) )
1740 return kWeakDefinition;
1741 else
1742 return kNoDefinitionOptions;
1743 }
1744
1745 const char* ImageLoaderMachO::getExportedSymbolName(const Symbol* sym) const
1746 {
1747 return exportedSymbolName(sym);
1748 }
1749
1750 uint32_t ImageLoaderMachO::getExportedSymbolCount() const
1751 {
1752 return exportedSymbolCount();
1753 }
1754
1755
1756 const ImageLoader::Symbol* ImageLoaderMachO::getIndexedExportedSymbol(uint32_t index) const
1757 {
1758 return exportedSymbolIndexed(index);
1759 }
1760
1761
1762 uint32_t ImageLoaderMachO::getImportedSymbolCount() const
1763 {
1764 return importedSymbolCount();
1765 }
1766
1767
1768 const ImageLoader::Symbol* ImageLoaderMachO::getIndexedImportedSymbol(uint32_t index) const
1769 {
1770 return importedSymbolIndexed(index);
1771 }
1772
1773
1774 ImageLoader::ReferenceFlags ImageLoaderMachO::getImportedSymbolInfo(const ImageLoader::Symbol* sym) const
1775 {
1776 ImageLoader::ReferenceFlags flags = kNoReferenceOptions;
1777 return flags;
1778 }
1779
1780
1781 const char* ImageLoaderMachO::getImportedSymbolName(const ImageLoader::Symbol* sym) const
1782 {
1783 return importedSymbolName(sym);
1784 }
1785
1786
1787 bool ImageLoaderMachO::getSectionContent(const char* segmentName, const char* sectionName, void** start, size_t* length)
1788 {
1789 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1790 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1791 const struct load_command* cmd = cmds;
1792 for (uint32_t i = 0; i < cmd_count; ++i) {
1793 switch (cmd->cmd) {
1794 case LC_SEGMENT_COMMAND:
1795 {
1796 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
1797 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
1798 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
1799 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
1800 if ( (strcmp(sect->segname, segmentName) == 0) && (strcmp(sect->sectname, sectionName) == 0) ) {
1801 *start = (uintptr_t*)(sect->addr + fSlide);
1802 *length = sect->size;
1803 return true;
1804 }
1805 }
1806 }
1807 break;
1808 }
1809 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1810 }
1811 *start = NULL;
1812 *length = 0;
1813 return false;
1814 }
1815
1816 void ImageLoaderMachO::getUnwindInfo(dyld_unwind_sections* info)
1817 {
1818 info->mh = this->machHeader();
1819 info->dwarf_section = 0;
1820 info->dwarf_section_length = 0;
1821 info->compact_unwind_section = 0;
1822 info->compact_unwind_section_length = 0;
1823 if ( fEHFrameSectionOffset != 0 ) {
1824 const macho_section* sect = (macho_section*)&fMachOData[fEHFrameSectionOffset];
1825 info->dwarf_section = (void*)(sect->addr + fSlide);
1826 info->dwarf_section_length = sect->size;
1827 }
1828 if ( fUnwindInfoSectionOffset != 0 ) {
1829 const macho_section* sect = (macho_section*)&fMachOData[fUnwindInfoSectionOffset];
1830 info->compact_unwind_section = (void*)(sect->addr + fSlide);
1831 info->compact_unwind_section_length = sect->size;
1832 }
1833 }
1834
1835 intptr_t ImageLoaderMachO::computeSlide(const mach_header* mh)
1836 {
1837 const uint32_t cmd_count = mh->ncmds;
1838 const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
1839 const load_command* cmd = cmds;
1840 for (uint32_t i = 0; i < cmd_count; ++i) {
1841 if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
1842 const macho_segment_command* seg = (macho_segment_command*)cmd;
1843 if ( strcmp(seg->segname, "__TEXT") == 0 )
1844 return (char*)mh - (char*)(seg->vmaddr);
1845 }
1846 cmd = (const load_command*)(((char*)cmd)+cmd->cmdsize);
1847 }
1848 return 0;
1849 }
1850
1851 bool ImageLoaderMachO::findSection(const mach_header* mh, const char* segmentName, const char* sectionName, void** sectAddress, size_t* sectSize)
1852 {
1853 const uint32_t cmd_count = mh->ncmds;
1854 const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
1855 const load_command* cmd = cmds;
1856 for (uint32_t i = 0; i < cmd_count; ++i) {
1857 switch (cmd->cmd) {
1858 case LC_SEGMENT_COMMAND:
1859 {
1860 const macho_segment_command* seg = (macho_segment_command*)cmd;
1861 const macho_section* const sectionsStart = (macho_section*)((char*)seg + sizeof(macho_segment_command));
1862 const macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
1863 for (const macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
1864 if ( (strcmp(sect->segname, segmentName) == 0) && (strcmp(sect->sectname, sectionName) == 0) ) {
1865 *sectAddress = (void*)(sect->addr + computeSlide(mh));
1866 *sectSize = sect->size;
1867 return true;
1868 }
1869 }
1870 }
1871 break;
1872 }
1873 cmd = (const load_command*)(((char*)cmd)+cmd->cmdsize);
1874 }
1875 return false;
1876 }
1877
1878
1879 bool ImageLoaderMachO::findSection(const void* imageInterior, const char** segmentName, const char** sectionName, size_t* sectionOffset)
1880 {
1881 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1882 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1883 const struct load_command* cmd = cmds;
1884 const uintptr_t unslidInteriorAddress = (uintptr_t)imageInterior - this->getSlide();
1885 for (uint32_t i = 0; i < cmd_count; ++i) {
1886 switch (cmd->cmd) {
1887 case LC_SEGMENT_COMMAND:
1888 {
1889 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
1890 if ( (unslidInteriorAddress >= seg->vmaddr) && (unslidInteriorAddress < (seg->vmaddr+seg->vmsize)) ) {
1891 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
1892 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
1893 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
1894 if ((sect->addr <= unslidInteriorAddress) && (unslidInteriorAddress < (sect->addr+sect->size))) {
1895 if ( segmentName != NULL )
1896 *segmentName = sect->segname;
1897 if ( sectionName != NULL )
1898 *sectionName = sect->sectname;
1899 if ( sectionOffset != NULL )
1900 *sectionOffset = unslidInteriorAddress - sect->addr;
1901 return true;
1902 }
1903 }
1904 }
1905 }
1906 break;
1907 }
1908 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1909 }
1910 return false;
1911 }
1912
1913 const char* ImageLoaderMachO::libPath(unsigned int index) const
1914 {
1915 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1916 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1917 const struct load_command* cmd = cmds;
1918 unsigned count = 0;
1919 for (uint32_t i = 0; i < cmd_count; ++i) {
1920 switch ( cmd->cmd ) {
1921 case LC_LOAD_DYLIB:
1922 case LC_LOAD_WEAK_DYLIB:
1923 case LC_REEXPORT_DYLIB:
1924 case LC_LOAD_UPWARD_DYLIB:
1925 if ( index == count ) {
1926 const struct dylib_command* dylibCmd = (struct dylib_command*)cmd;
1927 return (char*)cmd + dylibCmd->dylib.name.offset;
1928 }
1929 ++count;
1930 break;
1931 }
1932 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1933 }
1934
1935 // <rdar://problem/24256354> if image linked with nothing and we implicitly added libSystem.dylib, return that
1936 if ( needsAddedLibSystemDepency(libraryCount(), (macho_header*)fMachOData) ) {
1937 return LIBSYSTEM_DYLIB_PATH;
1938 }
1939
1940 return NULL;
1941 }
1942
1943
1944 void __attribute__((noreturn)) ImageLoaderMachO::throwSymbolNotFound(const LinkContext& context, const char* symbol,
1945 const char* referencedFrom, const char* fromVersMismatch,
1946 const char* expectedIn)
1947 {
1948 // record values for possible use by CrashReporter or Finder
1949 (*context.setErrorStrings)(DYLD_EXIT_REASON_SYMBOL_MISSING, referencedFrom, expectedIn, symbol);
1950 dyld::throwf("Symbol not found: %s\n Referenced from: %s%s\n Expected in: %s\n",
1951 symbol, referencedFrom, fromVersMismatch, expectedIn);
1952 }
1953
1954 const mach_header* ImageLoaderMachO::machHeader() const
1955 {
1956 return (mach_header*)fMachOData;
1957 }
1958
1959 uintptr_t ImageLoaderMachO::getSlide() const
1960 {
1961 return fSlide;
1962 }
1963
1964 // hmm. maybe this should be up in ImageLoader??
1965 const void* ImageLoaderMachO::getEnd() const
1966 {
1967 uintptr_t lastAddress = 0;
1968 for(unsigned int i=0; i < fSegmentsCount; ++i) {
1969 uintptr_t segEnd = segActualEndAddress(i);
1970 if ( strcmp(segName(i), "__UNIXSTACK") != 0 ) {
1971 if ( segEnd > lastAddress )
1972 lastAddress = segEnd;
1973 }
1974 }
1975 return (const void*)lastAddress;
1976 }
1977
1978
1979 uintptr_t ImageLoaderMachO::bindLocation(const LinkContext& context, uintptr_t location, uintptr_t value,
1980 uint8_t type, const char* symbolName,
1981 intptr_t addend, const char* inPath, const char* toPath, const char* msg)
1982 {
1983 // log
1984 if ( context.verboseBind ) {
1985 if ( addend != 0 )
1986 dyld::log("dyld: %sbind: %s:0x%08lX = %s:%s, *0x%08lX = 0x%08lX + %ld\n",
1987 msg, shortName(inPath), (uintptr_t)location,
1988 ((toPath != NULL) ? shortName(toPath) : "<missing weak_import>"),
1989 symbolName, (uintptr_t)location, value, addend);
1990 else
1991 dyld::log("dyld: %sbind: %s:0x%08lX = %s:%s, *0x%08lX = 0x%08lX\n",
1992 msg, shortName(inPath), (uintptr_t)location,
1993 ((toPath != NULL) ? shortName(toPath) : "<missing weak_import>"),
1994 symbolName, (uintptr_t)location, value);
1995 }
1996 #if LOG_BINDINGS
1997 // dyld::logBindings("%s: %s\n", targetImage->getShortName(), symbolName);
1998 #endif
1999
2000 // do actual update
2001 uintptr_t* locationToFix = (uintptr_t*)location;
2002 uint32_t* loc32;
2003 uintptr_t newValue = value+addend;
2004 uint32_t value32;
2005 switch (type) {
2006 case BIND_TYPE_POINTER:
2007 // test first so we don't needless dirty pages
2008 if ( *locationToFix != newValue )
2009 *locationToFix = newValue;
2010 break;
2011 case BIND_TYPE_TEXT_ABSOLUTE32:
2012 loc32 = (uint32_t*)locationToFix;
2013 value32 = (uint32_t)newValue;
2014 if ( *loc32 != value32 )
2015 *loc32 = value32;
2016 break;
2017 case BIND_TYPE_TEXT_PCREL32:
2018 loc32 = (uint32_t*)locationToFix;
2019 value32 = (uint32_t)(newValue - (((uintptr_t)locationToFix) + 4));
2020 if ( *loc32 != value32 )
2021 *loc32 = value32;
2022 break;
2023 default:
2024 dyld::throwf("bad bind type %d", type);
2025 }
2026
2027 // update statistics
2028 ++fgTotalBindFixups;
2029
2030 return newValue;
2031 }
2032
2033
2034
2035
2036
2037 #if SUPPORT_OLD_CRT_INITIALIZATION
2038 // first 16 bytes of "start" in crt1.o
2039 #if __i386__
2040 static uint8_t sStandardEntryPointInstructions[16] = { 0x6a, 0x00, 0x89, 0xe5, 0x83, 0xe4, 0xf0, 0x83, 0xec, 0x10, 0x8b, 0x5d, 0x04, 0x89, 0x5c, 0x24 };
2041 #endif
2042 #endif
2043
2044 struct DATAdyld {
2045 void* dyldLazyBinder; // filled in at launch by dyld to point into dyld to &stub_binding_helper
2046 void* dyldFuncLookup; // filled in at launch by dyld to point into dyld to &_dyld_func_lookup
2047 // the following only exist in main executables built for 10.5 or later
2048 ProgramVars vars;
2049 };
2050
2051 // These are defined in dyldStartup.s
2052 extern "C" void stub_binding_helper();
2053 extern "C" int _dyld_func_lookup(const char* name, void** address);
2054
2055 void ImageLoaderMachO::setupLazyPointerHandler(const LinkContext& context)
2056 {
2057 const macho_header* mh = (macho_header*)fMachOData;
2058 const uint32_t cmd_count = mh->ncmds;
2059 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
2060 const struct load_command* cmd;
2061 // There used to be some optimizations to skip this section scan, but we need to handle the
2062 // __dyld section in libdyld.dylib, so everything needs to be scanned for now.
2063 // <rdar://problem/10910062> CrashTracer: 1,295 crashes in bash at bash: getenv
2064 if ( true ) {
2065 cmd = cmds;
2066 for (uint32_t i = 0; i < cmd_count; ++i) {
2067 if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
2068 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
2069 if ( strncmp(seg->segname, "__DATA", 6) == 0 ) {
2070 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
2071 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
2072 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2073 if ( strcmp(sect->sectname, "__dyld" ) == 0 ) {
2074 struct DATAdyld* dd = (struct DATAdyld*)(sect->addr + fSlide);
2075 #if !__arm64__ && !__ARM_ARCH_7K__
2076 if ( sect->size > offsetof(DATAdyld, dyldLazyBinder) ) {
2077 if ( dd->dyldLazyBinder != (void*)&stub_binding_helper )
2078 dd->dyldLazyBinder = (void*)&stub_binding_helper;
2079 }
2080 #endif // !__arm64__
2081 if ( sect->size > offsetof(DATAdyld, dyldFuncLookup) ) {
2082 if ( dd->dyldFuncLookup != (void*)&_dyld_func_lookup )
2083 dd->dyldFuncLookup = (void*)&_dyld_func_lookup;
2084 }
2085 if ( mh->filetype == MH_EXECUTE ) {
2086 // there are two ways to get the program variables
2087 if ( (sect->size > offsetof(DATAdyld, vars)) && (dd->vars.mh == mh) ) {
2088 // some really old binaries have space for vars, but it is zero filled
2089 // main executable has 10.5 style __dyld section that has program variable pointers
2090 context.setNewProgramVars(dd->vars);
2091 }
2092 else {
2093 // main executable is pre-10.5 and requires the symbols names to be looked up
2094 this->lookupProgramVars(context);
2095 #if SUPPORT_OLD_CRT_INITIALIZATION
2096 // If the first 16 bytes of the entry point's instructions do not
2097 // match what crt1.o supplies, then the program has a custom entry point.
2098 // This means it might be doing something that needs to be executed before
2099 // initializers are run.
2100 if ( memcmp(this->getMain(), sStandardEntryPointInstructions, 16) != 0 ) {
2101 if ( context.verboseInit )
2102 dyld::log("dyld: program uses non-standard entry point so delaying running of initializers\n");
2103 context.setRunInitialzersOldWay();
2104 }
2105 #endif
2106 }
2107 }
2108 else if ( mh->filetype == MH_DYLIB ) {
2109 const char* installPath = this->getInstallPath();
2110 if ( (installPath != NULL) && (strncmp(installPath, "/usr/lib/", 9) == 0) ) {
2111 if ( sect->size > offsetof(DATAdyld, vars) ) {
2112 // use ProgramVars from libdyld.dylib but tweak mh field to correct value
2113 dd->vars.mh = context.mainExecutable->machHeader();
2114 context.setNewProgramVars(dd->vars);
2115 }
2116 }
2117 }
2118 }
2119 else if ( (strcmp(sect->sectname, "__program_vars" ) == 0) && (mh->filetype == MH_EXECUTE) ) {
2120 // this is a Mac OS X 10.6 or later main executable
2121 struct ProgramVars* pv = (struct ProgramVars*)(sect->addr + fSlide);
2122 context.setNewProgramVars(*pv);
2123 }
2124 }
2125 }
2126 }
2127 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2128 }
2129 }
2130 }
2131
2132
2133 void ImageLoaderMachO::lookupProgramVars(const LinkContext& context) const
2134 {
2135 ProgramVars vars = context.programVars;
2136 const ImageLoader::Symbol* sym;
2137
2138 // get mach header directly
2139 vars.mh = (macho_header*)fMachOData;
2140
2141 // lookup _NXArgc
2142 sym = this->findShallowExportedSymbol("_NXArgc", NULL);
2143 if ( sym != NULL )
2144 vars.NXArgcPtr = (int*)this->getExportedSymbolAddress(sym, context, this, false, NULL);
2145
2146 // lookup _NXArgv
2147 sym = this->findShallowExportedSymbol("_NXArgv", NULL);
2148 if ( sym != NULL )
2149 vars.NXArgvPtr = (const char***)this->getExportedSymbolAddress(sym, context, this, false, NULL);
2150
2151 // lookup _environ
2152 sym = this->findShallowExportedSymbol("_environ", NULL);
2153 if ( sym != NULL )
2154 vars.environPtr = (const char***)this->getExportedSymbolAddress(sym, context, this, false, NULL);
2155
2156 // lookup __progname
2157 sym = this->findShallowExportedSymbol("___progname", NULL);
2158 if ( sym != NULL )
2159 vars.__prognamePtr = (const char**)this->getExportedSymbolAddress(sym, context, this, false, NULL);
2160
2161 context.setNewProgramVars(vars);
2162 }
2163
2164
2165 bool ImageLoaderMachO::usablePrebinding(const LinkContext& context) const
2166 {
2167 // if prebound and loaded at prebound address, and all libraries are same as when this was prebound, then no need to bind
2168 if ( ((this->isPrebindable() && (this->getSlide() == 0)) || fInSharedCache)
2169 && this->usesTwoLevelNameSpace()
2170 && this->allDependentLibrariesAsWhenPreBound() ) {
2171 // allow environment variables to disable prebinding
2172 if ( context.bindFlat )
2173 return false;
2174 switch ( context.prebindUsage ) {
2175 case kUseAllPrebinding:
2176 return true;
2177 case kUseSplitSegPrebinding:
2178 return this->fIsSplitSeg;
2179 case kUseAllButAppPredbinding:
2180 return (this != context.mainExecutable);
2181 case kUseNoPrebinding:
2182 return false;
2183 }
2184 }
2185 return false;
2186 }
2187
2188
2189 void ImageLoaderMachO::doImageInit(const LinkContext& context)
2190 {
2191 if ( fHasDashInit ) {
2192 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
2193 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
2194 const struct load_command* cmd = cmds;
2195 for (uint32_t i = 0; i < cmd_count; ++i) {
2196 switch (cmd->cmd) {
2197 case LC_ROUTINES_COMMAND:
2198 Initializer func = (Initializer)(((struct macho_routines_command*)cmd)->init_address + fSlide);
2199 // <rdar://problem/8543820&9228031> verify initializers are in image
2200 if ( ! this->containsAddress((void*)func) ) {
2201 dyld::throwf("initializer function %p not in mapped image for %s\n", func, this->getPath());
2202 }
2203 if ( ! dyld::gProcessInfo->libSystemInitialized ) {
2204 // <rdar://problem/17973316> libSystem initializer must run first
2205 dyld::throwf("-init function in image (%s) that does not link with libSystem.dylib\n", this->getPath());
2206 }
2207 if ( context.verboseInit )
2208 dyld::log("dyld: calling -init function %p in %s\n", func, this->getPath());
2209 dyld3::kdebug_trace_dyld_duration(DBG_DYLD_TIMING_STATIC_INITIALIZER, (uint64_t)func, 0, ^{
2210 func(context.argc, context.argv, context.envp, context.apple, &context.programVars);
2211 });
2212 break;
2213 }
2214 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2215 }
2216 }
2217 }
2218
2219 void ImageLoaderMachO::doModInitFunctions(const LinkContext& context)
2220 {
2221 if ( fHasInitializers ) {
2222 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
2223 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
2224 const struct load_command* cmd = cmds;
2225 for (uint32_t i = 0; i < cmd_count; ++i) {
2226 if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
2227 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
2228 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
2229 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
2230 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2231 const uint8_t type = sect->flags & SECTION_TYPE;
2232 if ( type == S_MOD_INIT_FUNC_POINTERS ) {
2233 Initializer* inits = (Initializer*)(sect->addr + fSlide);
2234 const size_t count = sect->size / sizeof(uintptr_t);
2235 // <rdar://problem/23929217> Ensure __mod_init_func section is within segment
2236 if ( (sect->addr < seg->vmaddr) || (sect->addr+sect->size > seg->vmaddr+seg->vmsize) || (sect->addr+sect->size < sect->addr) )
2237 dyld::throwf("__mod_init_funcs section has malformed address range for %s\n", this->getPath());
2238 for (size_t j=0; j < count; ++j) {
2239 Initializer func = inits[j];
2240 // <rdar://problem/8543820&9228031> verify initializers are in image
2241 if ( ! this->containsAddress((void*)func) ) {
2242 dyld::throwf("initializer function %p not in mapped image for %s\n", func, this->getPath());
2243 }
2244 if ( ! dyld::gProcessInfo->libSystemInitialized ) {
2245 // <rdar://problem/17973316> libSystem initializer must run first
2246 const char* installPath = getInstallPath();
2247 if ( (installPath == NULL) || (strcmp(installPath, LIBSYSTEM_DYLIB_PATH) != 0) )
2248 dyld::throwf("initializer in image (%s) that does not link with libSystem.dylib\n", this->getPath());
2249 }
2250 if ( context.verboseInit )
2251 dyld::log("dyld: calling initializer function %p in %s\n", func, this->getPath());
2252 bool haveLibSystemHelpersBefore = (dyld::gLibSystemHelpers != NULL);
2253 dyld3::kdebug_trace_dyld_duration(DBG_DYLD_TIMING_STATIC_INITIALIZER, (uint64_t)func, 0, ^{
2254 func(context.argc, context.argv, context.envp, context.apple, &context.programVars);
2255 });
2256 bool haveLibSystemHelpersAfter = (dyld::gLibSystemHelpers != NULL);
2257 if ( !haveLibSystemHelpersBefore && haveLibSystemHelpersAfter ) {
2258 // now safe to use malloc() and other calls in libSystem.dylib
2259 dyld::gProcessInfo->libSystemInitialized = true;
2260 }
2261 }
2262 }
2263 }
2264 }
2265 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2266 }
2267 }
2268 }
2269
2270
2271
2272 void ImageLoaderMachO::doGetDOFSections(const LinkContext& context, std::vector<ImageLoader::DOFInfo>& dofs)
2273 {
2274 if ( fHasDOFSections ) {
2275 // walk load commands (mapped in at start of __TEXT segment)
2276 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
2277 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
2278 const struct load_command* cmd = cmds;
2279 for (uint32_t i = 0; i < cmd_count; ++i) {
2280 switch (cmd->cmd) {
2281 case LC_SEGMENT_COMMAND:
2282 {
2283 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
2284 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
2285 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
2286 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2287 if ( (sect->flags & SECTION_TYPE) == S_DTRACE_DOF ) {
2288 // <rdar://problem/23929217> Ensure section is within segment
2289 if ( (sect->addr < seg->vmaddr) || (sect->addr+sect->size > seg->vmaddr+seg->vmsize) || (sect->addr+sect->size < sect->addr) )
2290 dyld::throwf("DOF section has malformed address range for %s\n", this->getPath());
2291 ImageLoader::DOFInfo info;
2292 info.dof = (void*)(sect->addr + fSlide);
2293 info.imageHeader = this->machHeader();
2294 info.imageShortName = this->getShortName();
2295 dofs.push_back(info);
2296 }
2297 }
2298 }
2299 break;
2300 }
2301 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2302 }
2303 }
2304 }
2305
2306
2307 bool ImageLoaderMachO::doInitialization(const LinkContext& context)
2308 {
2309 CRSetCrashLogMessage2(this->getPath());
2310
2311 // mach-o has -init and static initializers
2312 doImageInit(context);
2313 doModInitFunctions(context);
2314
2315 CRSetCrashLogMessage2(NULL);
2316
2317 return (fHasDashInit || fHasInitializers);
2318 }
2319
2320 bool ImageLoaderMachO::needsInitialization()
2321 {
2322 return ( fHasDashInit || fHasInitializers );
2323 }
2324
2325
2326 bool ImageLoaderMachO::needsTermination()
2327 {
2328 return fHasTerminators;
2329 }
2330
2331
2332 void ImageLoaderMachO::doTermination(const LinkContext& context)
2333 {
2334 if ( fHasTerminators ) {
2335 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
2336 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
2337 const struct load_command* cmd = cmds;
2338 for (uint32_t i = 0; i < cmd_count; ++i) {
2339 if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
2340 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
2341 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
2342 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
2343 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2344 const uint8_t type = sect->flags & SECTION_TYPE;
2345 if ( type == S_MOD_TERM_FUNC_POINTERS ) {
2346 // <rdar://problem/23929217> Ensure section is within segment
2347 if ( (sect->addr < seg->vmaddr) || (sect->addr+sect->size > seg->vmaddr+seg->vmsize) || (sect->addr+sect->size < sect->addr) )
2348 dyld::throwf("DOF section has malformed address range for %s\n", this->getPath());
2349 Terminator* terms = (Terminator*)(sect->addr + fSlide);
2350 const size_t count = sect->size / sizeof(uintptr_t);
2351 for (size_t j=count; j > 0; --j) {
2352 Terminator func = terms[j-1];
2353 // <rdar://problem/8543820&9228031> verify terminators are in image
2354 if ( ! this->containsAddress((void*)func) ) {
2355 dyld::throwf("termination function %p not in mapped image for %s\n", func, this->getPath());
2356 }
2357 if ( context.verboseInit )
2358 dyld::log("dyld: calling termination function %p in %s\n", func, this->getPath());
2359 func();
2360 }
2361 }
2362 }
2363 }
2364 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2365 }
2366 }
2367 }
2368
2369
2370 void ImageLoaderMachO::printStatisticsDetails(unsigned int imageCount, const InitializerTimingList& timingInfo)
2371 {
2372 ImageLoader::printStatisticsDetails(imageCount, timingInfo);
2373 dyld::log("total symbol trie searches: %d\n", fgSymbolTrieSearchs);
2374 dyld::log("total symbol table binary searches: %d\n", fgSymbolTableBinarySearchs);
2375 dyld::log("total images defining weak symbols: %u\n", fgImagesHasWeakDefinitions);
2376 dyld::log("total images using weak symbols: %u\n", fgImagesRequiringCoalescing);
2377 }
2378
2379
2380 intptr_t ImageLoaderMachO::assignSegmentAddresses(const LinkContext& context)
2381 {
2382 // preflight and calculate slide if needed
2383 const bool inPIE = (fgNextPIEDylibAddress != 0);
2384 intptr_t slide = 0;
2385 if ( this->segmentsCanSlide() && this->segmentsMustSlideTogether() ) {
2386 bool needsToSlide = false;
2387 bool imageHasPreferredLoadAddress = segHasPreferredLoadAddress(0);
2388 uintptr_t lowAddr = (unsigned long)(-1);
2389 uintptr_t highAddr = 0;
2390 for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
2391 const uintptr_t segLow = segPreferredLoadAddress(i);
2392 const uintptr_t segHigh = dyld_page_round(segLow + segSize(i));
2393 if ( segLow < highAddr ) {
2394 if ( dyld_page_size > 4096 )
2395 dyld::throwf("can't map segments into 16KB pages");
2396 else
2397 dyld::throwf("overlapping segments");
2398 }
2399 if ( segLow < lowAddr )
2400 lowAddr = segLow;
2401 if ( segHigh > highAddr )
2402 highAddr = segHigh;
2403
2404 if ( needsToSlide || !imageHasPreferredLoadAddress || inPIE || !reserveAddressRange(segPreferredLoadAddress(i), segSize(i)) )
2405 needsToSlide = true;
2406 }
2407 if ( needsToSlide ) {
2408 // find a chunk of address space to hold all segments
2409 uintptr_t addr = reserveAnAddressRange(highAddr-lowAddr, context);
2410 slide = addr - lowAddr;
2411 }
2412 }
2413 else if ( ! this->segmentsCanSlide() ) {
2414 for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
2415 if ( (strcmp(segName(i), "__PAGEZERO") == 0) && (segFileSize(i) == 0) && (segPreferredLoadAddress(i) == 0) )
2416 continue;
2417 if ( !reserveAddressRange(segPreferredLoadAddress(i), segSize(i)) )
2418 dyld::throwf("can't map unslidable segment %s to 0x%lX with size 0x%lX", segName(i), segPreferredLoadAddress(i), segSize(i));
2419 }
2420 }
2421 else {
2422 throw "mach-o does not support independently sliding segments";
2423 }
2424 return slide;
2425 }
2426
2427
2428 uintptr_t ImageLoaderMachO::reserveAnAddressRange(size_t length, const ImageLoader::LinkContext& context)
2429 {
2430 vm_address_t addr = 0;
2431 vm_size_t size = length;
2432 // in PIE programs, load initial dylibs after main executable so they don't have fixed addresses either
2433 if ( fgNextPIEDylibAddress != 0 ) {
2434 // add small (0-3 pages) random padding between dylibs
2435 addr = fgNextPIEDylibAddress + (__stack_chk_guard/fgNextPIEDylibAddress & (sizeof(long)-1))*dyld_page_size;
2436 //dyld::log("padding 0x%08llX, guard=0x%08llX\n", (long long)(addr - fgNextPIEDylibAddress), (long long)(__stack_chk_guard));
2437 kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_FIXED | VM_MAKE_TAG(VM_MEMORY_DYLIB));
2438 if ( r == KERN_SUCCESS ) {
2439 fgNextPIEDylibAddress = addr + size;
2440 return addr;
2441 }
2442 fgNextPIEDylibAddress = 0;
2443 }
2444 kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_ANYWHERE | VM_MAKE_TAG(VM_MEMORY_DYLIB));
2445 if ( r != KERN_SUCCESS )
2446 throw "out of address space";
2447
2448 return addr;
2449 }
2450
2451 bool ImageLoaderMachO::reserveAddressRange(uintptr_t start, size_t length)
2452 {
2453 vm_address_t addr = start;
2454 vm_size_t size = length;
2455 kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_FIXED | VM_MAKE_TAG(VM_MEMORY_DYLIB));
2456 if ( r != KERN_SUCCESS )
2457 return false;
2458 return true;
2459 }
2460
2461
2462
2463 void ImageLoaderMachO::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInFat, uint64_t fileLen, const LinkContext& context)
2464 {
2465 // find address range for image
2466 intptr_t slide = this->assignSegmentAddresses(context);
2467 if ( context.verboseMapping ) {
2468 if ( offsetInFat != 0 )
2469 dyld::log("dyld: Mapping %s (slice offset=%llu)\n", this->getPath(), (unsigned long long)offsetInFat);
2470 else
2471 dyld::log("dyld: Mapping %s\n", this->getPath());
2472 }
2473 // map in all segments
2474 for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
2475 vm_offset_t fileOffset = (vm_offset_t)(segFileOffset(i) + offsetInFat);
2476 vm_size_t size = segFileSize(i);
2477 uintptr_t requestedLoadAddress = segPreferredLoadAddress(i) + slide;
2478 int protection = 0;
2479 if ( !segUnaccessible(i) ) {
2480 // If has text-relocs, don't set x-bit initially.
2481 // Instead set it later after text-relocs have been done.
2482 if ( segExecutable(i) && !(segHasRebaseFixUps(i) && (slide != 0)) )
2483 protection |= PROT_EXEC;
2484 if ( segReadable(i) )
2485 protection |= PROT_READ;
2486 if ( segWriteable(i) ) {
2487 protection |= PROT_WRITE;
2488 // rdar://problem/22525618 force __LINKEDIT to always be mapped read-only
2489 if ( strcmp(segName(i), "__LINKEDIT") == 0 )
2490 protection = PROT_READ;
2491 }
2492 }
2493 #if __i386__
2494 // initially map __IMPORT segments R/W so dyld can update them
2495 if ( segIsReadOnlyImport(i) )
2496 protection |= PROT_WRITE;
2497 #endif
2498 // wholly zero-fill segments have nothing to mmap() in
2499 if ( size > 0 ) {
2500 if ( (fileOffset+size) > fileLen ) {
2501 dyld::throwf("truncated mach-o error: segment %s extends to %llu which is past end of file %llu",
2502 segName(i), (uint64_t)(fileOffset+size), fileLen);
2503 }
2504 void* loadAddress = xmmap((void*)requestedLoadAddress, size, protection, MAP_FIXED | MAP_PRIVATE, fd, fileOffset);
2505 if ( loadAddress == ((void*)(-1)) ) {
2506 int mmapErr = errno;
2507 if ( mmapErr == EPERM ) {
2508 if ( dyld::sandboxBlockedMmap(getPath()) )
2509 dyld::throwf("file system sandbox blocked mmap() of '%s'", this->getPath());
2510 else
2511 dyld::throwf("code signing blocked mmap() of '%s'", this->getPath());
2512 }
2513 else
2514 dyld::throwf("mmap() errno=%d at address=0x%08lX, size=0x%08lX segment=%s in Segment::map() mapping %s",
2515 mmapErr, requestedLoadAddress, (uintptr_t)size, segName(i), getPath());
2516 }
2517 }
2518 // update stats
2519 ++ImageLoader::fgTotalSegmentsMapped;
2520 ImageLoader::fgTotalBytesMapped += size;
2521 if ( context.verboseMapping )
2522 dyld::log("%18s at 0x%08lX->0x%08lX with permissions %c%c%c\n", segName(i), requestedLoadAddress, requestedLoadAddress+size-1,
2523 (protection & PROT_READ) ? 'r' : '.', (protection & PROT_WRITE) ? 'w' : '.', (protection & PROT_EXEC) ? 'x' : '.' );
2524 }
2525
2526 // update slide to reflect load location
2527 this->setSlide(slide);
2528 }
2529
2530 void ImageLoaderMachO::mapSegments(const void* memoryImage, uint64_t imageLen, const LinkContext& context)
2531 {
2532 // find address range for image
2533 intptr_t slide = this->assignSegmentAddresses(context);
2534 if ( context.verboseMapping )
2535 dyld::log("dyld: Mapping memory %p\n", memoryImage);
2536 // map in all segments
2537 for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
2538 vm_address_t loadAddress = segPreferredLoadAddress(i) + slide;
2539 vm_address_t srcAddr = (uintptr_t)memoryImage + segFileOffset(i);
2540 vm_size_t size = segFileSize(i);
2541 kern_return_t r = vm_copy(mach_task_self(), srcAddr, size, loadAddress);
2542 if ( r != KERN_SUCCESS )
2543 throw "can't map segment";
2544 if ( context.verboseMapping )
2545 dyld::log("%18s at 0x%08lX->0x%08lX\n", segName(i), (uintptr_t)loadAddress, (uintptr_t)loadAddress+size-1);
2546 }
2547 // update slide to reflect load location
2548 this->setSlide(slide);
2549 // set R/W permissions on all segments at slide location
2550 for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
2551 segProtect(i, context);
2552 }
2553 }
2554
2555
2556 void ImageLoaderMachO::segProtect(unsigned int segIndex, const ImageLoader::LinkContext& context)
2557 {
2558 vm_prot_t protection = 0;
2559 if ( !segUnaccessible(segIndex) ) {
2560 if ( segExecutable(segIndex) )
2561 protection |= PROT_EXEC;
2562 if ( segReadable(segIndex) )
2563 protection |= PROT_READ;
2564 if ( segWriteable(segIndex) )
2565 protection |= PROT_WRITE;
2566 }
2567 vm_address_t addr = segActualLoadAddress(segIndex);
2568 vm_size_t size = segSize(segIndex);
2569 const bool setCurrentPermissions = false;
2570 kern_return_t r = vm_protect(mach_task_self(), addr, size, setCurrentPermissions, protection);
2571 if ( r != KERN_SUCCESS ) {
2572 dyld::throwf("vm_protect(0x%08llX, 0x%08llX, false, 0x%02X) failed, result=%d for segment %s in %s",
2573 (long long)addr, (long long)size, protection, r, segName(segIndex), this->getPath());
2574 }
2575 if ( context.verboseMapping ) {
2576 dyld::log("%18s at 0x%08lX->0x%08lX altered permissions to %c%c%c\n", segName(segIndex), (uintptr_t)addr, (uintptr_t)addr+size-1,
2577 (protection & PROT_READ) ? 'r' : '.', (protection & PROT_WRITE) ? 'w' : '.', (protection & PROT_EXEC) ? 'x' : '.' );
2578 }
2579 }
2580
2581 void ImageLoaderMachO::segMakeWritable(unsigned int segIndex, const ImageLoader::LinkContext& context)
2582 {
2583 vm_address_t addr = segActualLoadAddress(segIndex);
2584 vm_size_t size = segSize(segIndex);
2585 const bool setCurrentPermissions = false;
2586 vm_prot_t protection = VM_PROT_WRITE | VM_PROT_READ;
2587 if ( segExecutable(segIndex) && !segHasRebaseFixUps(segIndex) )
2588 protection |= VM_PROT_EXECUTE;
2589 kern_return_t r = vm_protect(mach_task_self(), addr, size, setCurrentPermissions, protection);
2590 if ( r != KERN_SUCCESS ) {
2591 dyld::throwf("vm_protect(0x%08llX, 0x%08llX, false, 0x%02X) failed, result=%d for segment %s in %s",
2592 (long long)addr, (long long)size, protection, r, segName(segIndex), this->getPath());
2593 }
2594 if ( context.verboseMapping ) {
2595 dyld::log("%18s at 0x%08lX->0x%08lX altered permissions to %c%c%c\n", segName(segIndex), (uintptr_t)addr, (uintptr_t)addr+size-1,
2596 (protection & PROT_READ) ? 'r' : '.', (protection & PROT_WRITE) ? 'w' : '.', (protection & PROT_EXEC) ? 'x' : '.' );
2597 }
2598 }
2599
2600
2601 const char* ImageLoaderMachO::findClosestSymbol(const mach_header* mh, const void* addr, const void** closestAddr)
2602 {
2603 // called by dladdr()
2604 // only works with compressed LINKEDIT if classic symbol table is also present
2605 const dysymtab_command* dynSymbolTable = NULL;
2606 const symtab_command* symtab = NULL;
2607 const macho_segment_command* seg;
2608 const uint8_t* unslidLinkEditBase = NULL;
2609 bool linkEditBaseFound = false;
2610 intptr_t slide = 0;
2611 const uint32_t cmd_count = mh->ncmds;
2612 const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
2613 const load_command* cmd = cmds;
2614 for (uint32_t i = 0; i < cmd_count; ++i) {
2615 switch (cmd->cmd) {
2616 case LC_SEGMENT_COMMAND:
2617 seg = (macho_segment_command*)cmd;
2618 if ( strcmp(seg->segname, "__LINKEDIT") == 0 ) {
2619 unslidLinkEditBase = (uint8_t*)(seg->vmaddr - seg->fileoff);
2620 linkEditBaseFound = true;
2621 }
2622 else if ( strcmp(seg->segname, "__TEXT") == 0 ) {
2623 slide = (uintptr_t)mh - seg->vmaddr;
2624 }
2625 break;
2626 case LC_SYMTAB:
2627 symtab = (symtab_command*)cmd;
2628 break;
2629 case LC_DYSYMTAB:
2630 dynSymbolTable = (dysymtab_command*)cmd;
2631 break;
2632 }
2633 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2634 }
2635 // no symbol table => no lookup by address
2636 if ( (symtab == NULL) || (dynSymbolTable == NULL) || !linkEditBaseFound )
2637 return NULL;
2638
2639 const uint8_t* linkEditBase = unslidLinkEditBase + slide;
2640 const char* symbolTableStrings = (const char*)&linkEditBase[symtab->stroff];
2641 const macho_nlist* symbolTable = (macho_nlist*)(&linkEditBase[symtab->symoff]);
2642
2643 uintptr_t targetAddress = (uintptr_t)addr - slide;
2644 const struct macho_nlist* bestSymbol = NULL;
2645 // first walk all global symbols
2646 const struct macho_nlist* const globalsStart = &symbolTable[dynSymbolTable->iextdefsym];
2647 const struct macho_nlist* const globalsEnd= &globalsStart[dynSymbolTable->nextdefsym];
2648 for (const struct macho_nlist* s = globalsStart; s < globalsEnd; ++s) {
2649 if ( (s->n_type & N_TYPE) == N_SECT ) {
2650 if ( bestSymbol == NULL ) {
2651 if ( s->n_value <= targetAddress )
2652 bestSymbol = s;
2653 }
2654 else if ( (s->n_value <= targetAddress) && (bestSymbol->n_value < s->n_value) ) {
2655 bestSymbol = s;
2656 }
2657 }
2658 }
2659 // next walk all local symbols
2660 const struct macho_nlist* const localsStart = &symbolTable[dynSymbolTable->ilocalsym];
2661 const struct macho_nlist* const localsEnd= &localsStart[dynSymbolTable->nlocalsym];
2662 for (const struct macho_nlist* s = localsStart; s < localsEnd; ++s) {
2663 if ( ((s->n_type & N_TYPE) == N_SECT) && ((s->n_type & N_STAB) == 0) ) {
2664 if ( bestSymbol == NULL ) {
2665 if ( s->n_value <= targetAddress )
2666 bestSymbol = s;
2667 }
2668 else if ( (s->n_value <= targetAddress) && (bestSymbol->n_value < s->n_value) ) {
2669 bestSymbol = s;
2670 }
2671 }
2672 }
2673 if ( bestSymbol != NULL ) {
2674 #if __arm__
2675 if (bestSymbol->n_desc & N_ARM_THUMB_DEF)
2676 *closestAddr = (void*)((bestSymbol->n_value | 1) + slide);
2677 else
2678 *closestAddr = (void*)(bestSymbol->n_value + slide);
2679 #else
2680 *closestAddr = (void*)(bestSymbol->n_value + slide);
2681 #endif
2682 return &symbolTableStrings[bestSymbol->n_un.n_strx];
2683 }
2684 return NULL;
2685 }
2686
2687 bool ImageLoaderMachO::getLazyBindingInfo(uint32_t& lazyBindingInfoOffset, const uint8_t* lazyInfoStart, const uint8_t* lazyInfoEnd,
2688 uint8_t* segIndex, uintptr_t* segOffset, int* ordinal, const char** symbolName, bool* doneAfterBind)
2689 {
2690 if ( lazyBindingInfoOffset > (lazyInfoEnd-lazyInfoStart) )
2691 return false;
2692 uint8_t type = BIND_TYPE_POINTER;
2693 uint8_t symboFlags = 0;
2694 bool done = false;
2695 const uint8_t* p = &lazyInfoStart[lazyBindingInfoOffset];
2696 while ( !done && (p < lazyInfoEnd) ) {
2697 uint8_t immediate = *p & BIND_IMMEDIATE_MASK;
2698 uint8_t opcode = *p & BIND_OPCODE_MASK;
2699 ++p;
2700 switch (opcode) {
2701 case BIND_OPCODE_DONE:
2702 *doneAfterBind = false;
2703 return true;
2704 break;
2705 case BIND_OPCODE_SET_DYLIB_ORDINAL_IMM:
2706 *ordinal = immediate;
2707 break;
2708 case BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB:
2709 *ordinal = (int)read_uleb128(p, lazyInfoEnd);
2710 break;
2711 case BIND_OPCODE_SET_DYLIB_SPECIAL_IMM:
2712 // the special ordinals are negative numbers
2713 if ( immediate == 0 )
2714 *ordinal = 0;
2715 else {
2716 int8_t signExtended = BIND_OPCODE_MASK | immediate;
2717 *ordinal = signExtended;
2718 }
2719 break;
2720 case BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM:
2721 *symbolName = (char*)p;
2722 symboFlags = immediate;
2723 while (*p != '\0')
2724 ++p;
2725 ++p;
2726 break;
2727 case BIND_OPCODE_SET_TYPE_IMM:
2728 type = immediate;
2729 break;
2730 case BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
2731 *segIndex = immediate;
2732 *segOffset = read_uleb128(p, lazyInfoEnd);
2733 break;
2734 case BIND_OPCODE_DO_BIND:
2735 *doneAfterBind = ((*p & BIND_OPCODE_MASK) == BIND_OPCODE_DONE);
2736 lazyBindingInfoOffset += p - &lazyInfoStart[lazyBindingInfoOffset];
2737 return true;
2738 break;
2739 case BIND_OPCODE_SET_ADDEND_SLEB:
2740 case BIND_OPCODE_ADD_ADDR_ULEB:
2741 case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
2742 case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
2743 case BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
2744 default:
2745 return false;
2746 }
2747 }
2748 return false;
2749 }
2750
2751 const dyld_info_command* ImageLoaderMachO::findDyldInfoLoadCommand(const mach_header* mh)
2752 {
2753 const uint32_t cmd_count = mh->ncmds;
2754 const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
2755 const load_command* cmd = cmds;
2756 for (uint32_t i = 0; i < cmd_count; ++i) {
2757 switch (cmd->cmd) {
2758 case LC_DYLD_INFO:
2759 case LC_DYLD_INFO_ONLY:
2760 return (dyld_info_command*)cmd;
2761 }
2762 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2763 }
2764 return NULL;
2765 }
2766
2767
2768 uintptr_t ImageLoaderMachO::segPreferredAddress(const mach_header* mh, unsigned segIndex)
2769 {
2770 const uint32_t cmd_count = mh->ncmds;
2771 const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
2772 const load_command* cmd = cmds;
2773 unsigned curSegIndex = 0;
2774 for (uint32_t i = 0; i < cmd_count; ++i) {
2775 if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
2776 if ( segIndex == curSegIndex ) {
2777 const macho_segment_command* segCmd = (macho_segment_command*)cmd;
2778 return segCmd->vmaddr;
2779 }
2780 ++curSegIndex;
2781 }
2782 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2783 }
2784 return 0;
2785 }
2786
2787
2788
mirror of dyld