]> git.saurik.com Git - apple/dyld.git/blobdiff - src/ImageLoaderMachO.cpp
dyld-353.2.3.tar.gz
[apple/dyld.git] / src / ImageLoaderMachO.cpp
index 3a8ad7d17e2096b3266d9ee15df7223e026c2c8c..53b0ddd1b21385c14bfead0af01173596d3d1f62 100644 (file)
 #include <mach-o/loader.h> 
 #include <mach-o/nlist.h> 
 #include <sys/sysctl.h>
+#include <sys/syscall.h>
 #include <libkern/OSAtomic.h>
 #include <libkern/OSCacheControl.h>
 #include <stdint.h>
+#include <System/sys/codesign.h>
 
 #include "ImageLoaderMachO.h"
 #include "ImageLoaderMachOCompressed.h"
+#if SUPPORT_CLASSIC_MACHO
 #include "ImageLoaderMachOClassic.h"
+#endif
 #include "mach-o/dyld_images.h"
 
 // <rdar://problem/8718137> use stack guard random value to add padding between dylibs
@@ -60,12 +64,14 @@ extern "C" long __stack_chk_guard;
 #if __LP64__
        #define LC_SEGMENT_COMMAND              LC_SEGMENT_64
        #define LC_ROUTINES_COMMAND             LC_ROUTINES_64
+       #define LC_SEGMENT_COMMAND_WRONG LC_SEGMENT
        struct macho_segment_command    : public segment_command_64  {};
        struct macho_section                    : public section_64  {};        
        struct macho_routines_command   : public routines_command_64  {};       
 #else
        #define LC_SEGMENT_COMMAND              LC_SEGMENT
        #define LC_ROUTINES_COMMAND             LC_ROUTINES
+       #define LC_SEGMENT_COMMAND_WRONG LC_SEGMENT_64
        struct macho_segment_command    : public segment_command {};
        struct macho_section                    : public section  {};   
        struct macho_routines_command   : public routines_command  {};  
@@ -103,7 +109,7 @@ ImageLoaderMachO::ImageLoaderMachO(const macho_header* mh, const char* path, uns
                        // ignore zero-sized segments
                        if ( segCmd->vmsize != 0 ) {
                                // record offset of load command
-                               segOffsets[segIndex++] = (uint8_t*)segCmd - fMachOData;
+                               segOffsets[segIndex++] = (uint32_t)((uint8_t*)segCmd - fMachOData);
                        }
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
@@ -114,7 +120,7 @@ ImageLoaderMachO::ImageLoaderMachO(const macho_header* mh, const char* path, uns
 
 // determine if this mach-o file has classic or compressed LINKEDIT and number of segments it has
 void ImageLoaderMachO::sniffLoadCommands(const macho_header* mh, const char* path, bool* compressed, 
-                                                                                       unsigned int* segCount, unsigned int* libCount,
+                                                                                       unsigned int* segCount, unsigned int* libCount, const LinkContext& context,
                                                                                        const linkedit_data_command** codeSigCmd)
 {
        *compressed = false;
@@ -122,14 +128,26 @@ void ImageLoaderMachO::sniffLoadCommands(const macho_header* mh, const char* pat
        *libCount = 0;
        *codeSigCmd = NULL;
        struct macho_segment_command* segCmd;
-#if CODESIGNING_SUPPORT
        bool foundLoadCommandSegment = false;
-#endif
+       uint32_t loadCommandSegmentIndex = 0xFFFFFFFF;
+       uintptr_t loadCommandSegmentVMStart = 0;
+       uintptr_t loadCommandSegmentVMEnd = 0;
+
        const uint32_t cmd_count = mh->ncmds;
        const struct load_command* const startCmds    = (struct load_command*)(((uint8_t*)mh) + sizeof(macho_header));
        const struct load_command* const endCmds = (struct load_command*)(((uint8_t*)mh) + sizeof(macho_header) + mh->sizeofcmds);
        const struct load_command* cmd = startCmds;
        for (uint32_t i = 0; i < cmd_count; ++i) {
+               uint32_t cmdLength = cmd->cmdsize;
+               if ( cmdLength < 8 ) {
+                       dyld::throwf("malformed mach-o image: load command #%d length (%u) too small in %s",
+                                                                                          i, cmdLength, path);
+               }
+               const struct load_command* const nextCmd = (const struct load_command*)(((char*)cmd)+cmdLength);
+               if ( (nextCmd > endCmds) || (nextCmd < cmd) ) {
+                       dyld::throwf("malformed mach-o image: load command #%d length (%u) would exceed sizeofcmds (%u) in %s",
+                                                                                          i, cmdLength, mh->sizeofcmds, path);
+               }
                switch (cmd->cmd) {
                        case LC_DYLD_INFO:
                        case LC_DYLD_INFO_ONLY:
@@ -140,16 +158,26 @@ void ImageLoaderMachO::sniffLoadCommands(const macho_header* mh, const char* pat
                                // ignore zero-sized segments
                                if ( segCmd->vmsize != 0 )
                                        *segCount += 1;
-#if CODESIGNING_SUPPORT
                                // <rdar://problem/7942521> all load commands must be in an executable segment
-                               if ( (segCmd->fileoff < mh->sizeofcmds) && (segCmd->filesize != 0) ) {
+                               if ( context.codeSigningEnforced && (segCmd->fileoff < mh->sizeofcmds) && (segCmd->filesize != 0) ) {
                                        if ( (segCmd->fileoff != 0) || (segCmd->filesize < (mh->sizeofcmds+sizeof(macho_header))) ) 
                                                dyld::throwf("malformed mach-o image: segment %s does not span all load commands", segCmd->segname); 
                                        if ( segCmd->initprot != (VM_PROT_READ | VM_PROT_EXECUTE) ) 
                                                dyld::throwf("malformed mach-o image: load commands found in segment %s with wrong permissions", segCmd->segname); 
+                                       if ( foundLoadCommandSegment )
+                                               throw "load commands in multiple segments";
                                        foundLoadCommandSegment = true;
+                                       loadCommandSegmentIndex = i;
+                                       loadCommandSegmentVMStart = segCmd->vmaddr;
+                                       loadCommandSegmentVMEnd   = segCmd->vmaddr + segCmd->vmsize;
+                                       if ( (intptr_t)(segCmd->vmsize) < 0)
+                                               dyld::throwf("malformed mach-o image: segment load command %s size too large", segCmd->segname);
+                                       if ( loadCommandSegmentVMEnd < loadCommandSegmentVMStart )
+                                               dyld::throwf("malformed mach-o image: segment load command %s wraps around address space", segCmd->segname);
                                }
-#endif         
+                               break;
+                       case LC_SEGMENT_COMMAND_WRONG:
+                               dyld::throwf("malformed mach-o image: wrong LC_SEGMENT[_64] for architecture"); 
                                break;
                        case LC_LOAD_DYLIB:
                        case LC_LOAD_WEAK_DYLIB:
@@ -161,19 +189,31 @@ void ImageLoaderMachO::sniffLoadCommands(const macho_header* mh, const char* pat
                                *codeSigCmd = (struct linkedit_data_command*)cmd; // only support one LC_CODE_SIGNATURE per image
                                break;
                }
-               uint32_t cmdLength = cmd->cmdsize;
-               cmd = (const struct load_command*)(((char*)cmd)+cmdLength);
-               if ( (cmd > endCmds) || (cmd < startCmds) ) {
-                       dyld::throwf("malformed mach-o image: load command #%d length (%u) would exceed sizeofcmds (%u) in %s", 
-                                                       i, cmdLength, mh->sizeofcmds, path);
-               }
+               cmd = nextCmd;
        }
        
-#if CODESIGNING_SUPPORT
-       if ( ! foundLoadCommandSegment )
+       if ( context.codeSigningEnforced && !foundLoadCommandSegment )
                throw "load commands not in a segment";
-#endif
-               
+       // <rdar://problem/13145644> verify another segment does not over-map load commands
+       cmd = startCmds;
+       if ( context.codeSigningEnforced ) {
+               for (uint32_t i = 0; i < cmd_count; ++i) {
+                       switch (cmd->cmd) {
+                               case LC_SEGMENT_COMMAND:
+                                       if ( i != loadCommandSegmentIndex ) {
+                                               segCmd = (struct macho_segment_command*)cmd;
+                                               uintptr_t start = segCmd->vmaddr;
+                                               uintptr_t end = segCmd->vmaddr + segCmd->vmsize;
+                                               if ( ((start <= loadCommandSegmentVMStart) && (end > loadCommandSegmentVMStart)) 
+                                                  || ((start >= loadCommandSegmentVMStart) && (start < loadCommandSegmentVMEnd)) )
+                                                       dyld::throwf("malformed mach-o image: segment %s overlaps load commands", segCmd->segname); 
+                                       }
+                                       break;
+                       }
+                       cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+               }
+       }
+       
        // fSegmentsArrayCount is only 8-bits
        if ( *segCount > 255 )
                dyld::throwf("malformed mach-o image: more than 255 segments in %s", path);
@@ -197,12 +237,16 @@ ImageLoader* ImageLoaderMachO::instantiateMainExecutable(const macho_header* mh,
        unsigned int segCount;
        unsigned int libCount;
        const linkedit_data_command* codeSigCmd;
-       sniffLoadCommands(mh, path, &compressed, &segCount, &libCount, &codeSigCmd);
+       sniffLoadCommands(mh, path, &compressed, &segCount, &libCount, context, &codeSigCmd);
        // instantiate concrete class based on content of load commands
        if ( compressed ) 
                return ImageLoaderMachOCompressed::instantiateMainExecutable(mh, slide, path, segCount, libCount, context);
        else
+#if SUPPORT_CLASSIC_MACHO
                return ImageLoaderMachOClassic::instantiateMainExecutable(mh, slide, path, segCount, libCount, context);
+#else
+               throw "missing LC_DYLD_INFO load command";
+#endif
 }
 
 
@@ -225,12 +269,16 @@ ImageLoader* ImageLoaderMachO::instantiateFromFile(const char* path, int fd, con
        unsigned int segCount;
        unsigned int libCount;
        const linkedit_data_command* codeSigCmd;
-       sniffLoadCommands((const macho_header*)fileData, path, &compressed, &segCount, &libCount, &codeSigCmd);
+       sniffLoadCommands((const macho_header*)fileData, path, &compressed, &segCount, &libCount, context, &codeSigCmd);
        // instantiate concrete class based on content of load commands
        if ( compressed ) 
                return ImageLoaderMachOCompressed::instantiateFromFile(path, fd, fileData, offsetInFat, lenInFat, info, segCount, libCount, codeSigCmd, context);
        else
+#if SUPPORT_CLASSIC_MACHO
                return ImageLoaderMachOClassic::instantiateFromFile(path, fd, fileData, offsetInFat, lenInFat, info, segCount, libCount, codeSigCmd, context);
+#else
+               throw "missing LC_DYLD_INFO load command";
+#endif
 }
 
 // create image by using cached mach-o file
@@ -241,12 +289,16 @@ ImageLoader* ImageLoaderMachO::instantiateFromCache(const macho_header* mh, cons
        unsigned int segCount;
        unsigned int libCount;
        const linkedit_data_command* codeSigCmd;
-       sniffLoadCommands(mh, path, &compressed, &segCount, &libCount, &codeSigCmd);
+       sniffLoadCommands(mh, path, &compressed, &segCount, &libCount, context, &codeSigCmd);
        // instantiate concrete class based on content of load commands
        if ( compressed ) 
                return ImageLoaderMachOCompressed::instantiateFromCache(mh, path, slide, info, segCount, libCount, context);
        else
+#if SUPPORT_CLASSIC_MACHO
                return ImageLoaderMachOClassic::instantiateFromCache(mh, path, slide, info, segCount, libCount, context);
+#else
+               throw "missing LC_DYLD_INFO load command";
+#endif
 }
 
 // create image by copying an in-memory mach-o file
@@ -256,15 +308,34 @@ ImageLoader* ImageLoaderMachO::instantiateFromMemory(const char* moduleName, con
        unsigned int segCount;
        unsigned int libCount;
        const linkedit_data_command* sigcmd;
-       sniffLoadCommands(mh, moduleName, &compressed, &segCount, &libCount, &sigcmd);
+       sniffLoadCommands(mh, moduleName, &compressed, &segCount, &libCount, context, &sigcmd);
        // instantiate concrete class based on content of load commands
        if ( compressed ) 
                return ImageLoaderMachOCompressed::instantiateFromMemory(moduleName, mh, len, segCount, libCount, context);
        else
+#if SUPPORT_CLASSIC_MACHO
                return ImageLoaderMachOClassic::instantiateFromMemory(moduleName, mh, len, segCount, libCount, context);
+#else
+               throw "missing LC_DYLD_INFO load command";
+#endif
 }
 
 
+int ImageLoaderMachO::crashIfInvalidCodeSignature()
+{
+       // Now that segments are mapped in, try reading from first executable segment.
+       // If code signing is enabled the kernel will validate the code signature
+       // when paging in, and kill the process if invalid.
+       for(unsigned int i=0; i < fSegmentsCount; ++i) {
+               if ( (segFileOffset(i) == 0) && (segFileSize(i) != 0) ) {
+                       // return read value to ensure compiler does not optimize away load
+                       int* p = (int*)segActualLoadAddress(i);
+                       return *p;
+               }
+       }
+       return 0;
+}
+
 
 void ImageLoaderMachO::parseLoadCmds()
 {
@@ -275,7 +346,7 @@ void ImageLoaderMachO::parseLoadCmds()
                        fLinkEditBase = (uint8_t*)(segActualLoadAddress(i) - segFileOffset(i));
 #if TEXT_RELOC_SUPPORT
                // __TEXT segment always starts at beginning of file and contains mach_header and load commands
-               if ( strcmp(segName(i),"__TEXT") == 0 ) {
+               if ( segExecutable(i) ) {
                        if ( segHasRebaseFixUps(i) && (fSlide != 0) )
                                fTextSegmentRebases = true;
                        if ( segHasBindFixUps(i) )
@@ -357,9 +428,9 @@ void ImageLoaderMachO::parseLoadCmds()
                                                else if ( type == S_DTRACE_DOF )
                                                        fHasDOFSections = true;
                                                else if ( isTextSeg && (strcmp(sect->sectname, "__eh_frame") == 0) )
-                                                       fEHFrameSectionOffset = (uint8_t*)sect - fMachOData;
+                                                       fEHFrameSectionOffset = (uint32_t)((uint8_t*)sect - fMachOData);
                                                else if ( isTextSeg && (strcmp(sect->sectname, "__unwind_info") == 0) )
-                                                       fUnwindInfoSectionOffset = (uint8_t*)sect - fMachOData;;
+                                                       fUnwindInfoSectionOffset = (uint32_t)((uint8_t*)sect - fMachOData);
                                        }
                                }
                                break;
@@ -368,7 +439,7 @@ void ImageLoaderMachO::parseLoadCmds()
                                break;
                        case LC_ID_DYLIB:
                                {
-                                       fDylibIDOffset = (uint8_t*)cmd - fMachOData;
+                                       fDylibIDOffset = (uint32_t)((uint8_t*)cmd - fMachOData);
                                }
                                break;
                        case LC_RPATH:
@@ -520,6 +591,7 @@ uintptr_t ImageLoaderMachO::segActualEndAddress(unsigned int segIndex) const
 
 bool ImageLoaderMachO::segHasRebaseFixUps(unsigned int segIndex) const
 {
+#if TEXT_RELOC_SUPPORT
        // scan sections for fix-up bit
        const macho_segment_command* segCmd = segLoadCommand(segIndex);
        const struct macho_section* const sectionsStart = (struct macho_section*)((char*)segCmd + sizeof(struct macho_segment_command));
@@ -528,11 +600,13 @@ bool ImageLoaderMachO::segHasRebaseFixUps(unsigned int segIndex) const
                if ( (sect->flags & S_ATTR_LOC_RELOC) != 0 )
                        return true;
        }
+#endif
        return false;
 }
 
 bool ImageLoaderMachO::segHasBindFixUps(unsigned int segIndex) const
 {
+#if TEXT_RELOC_SUPPORT
        // scan sections for fix-up bit
        const macho_segment_command* segCmd = segLoadCommand(segIndex);
        const struct macho_section* const sectionsStart = (struct macho_section*)((char*)segCmd + sizeof(struct macho_segment_command));
@@ -541,6 +615,7 @@ bool ImageLoaderMachO::segHasBindFixUps(unsigned int segIndex) const
                if ( (sect->flags & S_ATTR_EXT_RELOC) != 0 )
                        return true;
        }
+#endif
        return false;
 }
 
@@ -590,7 +665,7 @@ void ImageLoaderMachO::preFetchDATA(int fd, uint64_t offsetInFat, const LinkCont
                                // prefetch writable segment that have mmap'ed regions
                                radvisory advice;
                                advice.ra_offset = offsetInFat + segFileOffset(i);
-                               advice.ra_count = segFileSize(i);
+                               advice.ra_count = (int)segFileSize(i);
                                // limit prefetch to 1MB (256 pages)
                                if ( advice.ra_count > 1024*1024 )
                                        advice.ra_count = 1024*1024;
@@ -689,19 +764,57 @@ void ImageLoaderMachO::setSlide(intptr_t slide)
        fSlide = slide;
 }
 
-#if CODESIGNING_SUPPORT
-void ImageLoaderMachO::loadCodeSignature(const struct linkedit_data_command* codeSigCmd, int fd,  uint64_t offsetInFatFile)
+void ImageLoaderMachO::loadCodeSignature(const struct linkedit_data_command* codeSigCmd, int fd,  uint64_t offsetInFatFile, const LinkContext& context)
 {
-       fsignatures_t siginfo;
-       siginfo.fs_file_start=offsetInFatFile;                  // start of mach-o slice in fat file 
-       siginfo.fs_blob_start=(void*)(codeSigCmd->dataoff);     // start of CD in mach-o file
-       siginfo.fs_blob_size=codeSigCmd->datasize;                      // size of CD
-       int result = fcntl(fd, F_ADDFILESIGS, &siginfo);
-       if ( result == -1 ) 
-               dyld::log("dyld: F_ADDFILESIGS failed for %s with errno=%d\n", this->getPath(), errno);
-       //dyld::log("dyld: registered code signature for %s\n", this->getPath());
-}
+       // if dylib being loaded has no code signature load command
+       if ( codeSigCmd == NULL ) {
+#if __MAC_OS_X_VERSION_MIN_REQUIRED
+               bool codeSigningEnforced = context.codeSigningEnforced;
+               if ( context.mainExecutableCodeSigned && !codeSigningEnforced ) {
+                       static bool codeSignEnforcementDynamicallyEnabled = false;
+                       if ( !codeSignEnforcementDynamicallyEnabled ) {
+                               uint32_t flags;
+                               if ( csops(0, CS_OPS_STATUS, &flags, sizeof(flags)) != -1 ) {
+                                       if ( flags & CS_ENFORCEMENT ) {
+                                               codeSignEnforcementDynamicallyEnabled = true;
+                                       }
+                               }
+                       }
+                       codeSigningEnforced = codeSignEnforcementDynamicallyEnabled;
+               }
+               // if we require dylibs to be code signed
+               if ( codeSigningEnforced  ) {
+                       // if there is a non-load command based code signature, use it
+                       off_t offset = (off_t)offsetInFatFile;
+                       if ( fcntl(fd, F_FINDSIGS, &offset, sizeof(offset)) != -1 )
+                               return;
+                       // otherwise gracefully return from dlopen()
+                       dyld::throwf("required code signature missing for '%s'\n", this->getPath());
+               }
+#endif
+       }
+       else {
+#if __MAC_OS_X_VERSION_MIN_REQUIRED
+               // <rdar://problem/13622786> ignore code signatures in binaries built with pre-10.9 tools
+               if ( this->sdkVersion() < DYLD_MACOSX_VERSION_10_9 ) {
+                       return;
+               }
 #endif
+               fsignatures_t siginfo;
+               siginfo.fs_file_start=offsetInFatFile;                          // start of mach-o slice in fat file 
+               siginfo.fs_blob_start=(void*)(long)(codeSigCmd->dataoff);       // start of CD in mach-o file
+               siginfo.fs_blob_size=codeSigCmd->datasize;                      // size of CD
+               int result = fcntl(fd, F_ADDFILESIGS, &siginfo);
+               if ( result == -1 ) {
+                       if ( (errno == EPERM) || (errno == EBADEXEC) )
+                               dyld::throwf("code signature invalid for '%s'\n", this->getPath());
+                       if ( context.verboseCodeSignatures ) 
+                               dyld::log("dyld: Failed registering code signature for %s, errno=%d\n", this->getPath(), errno);
+                       else
+                               dyld::log("dyld: Registered code signature for %s\n", this->getPath());
+               }
+       }
+}
 
 
 const char* ImageLoaderMachO::getInstallPath() const
@@ -730,14 +843,16 @@ void ImageLoaderMachO::registerInterposing()
                                        for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
                                                if ( ((sect->flags & SECTION_TYPE) == S_INTERPOSING) || ((strcmp(sect->sectname, "__interpose") == 0) && (strcmp(seg->segname, "__DATA") == 0)) ) {
                                                        const InterposeData* interposeArray = (InterposeData*)(sect->addr + fSlide);
-                                                       const unsigned int count = sect->size / sizeof(InterposeData);
-                                                       for (uint32_t i=0; i < count; ++i) {
+                                                       const size_t count = sect->size / sizeof(InterposeData);
+                                                       for (size_t i=0; i < count; ++i) {
                                                                ImageLoader::InterposeTuple tuple;
                                                                tuple.replacement               = interposeArray[i].replacement;
-                                                               tuple.replacementImage  = this;
+                                                               tuple.neverImage                = this;
+                                                               tuple.onlyImage             = NULL;
                                                                tuple.replacee                  = interposeArray[i].replacee;
                                                                // <rdar://problem/7937695> verify that replacement is in this image
                                                                if ( this->containsAddress((void*)tuple.replacement) ) {
+                                                                       // chain to any existing interpositions
                                                                        for (std::vector<InterposeTuple>::iterator it=fgInterposingTuples.begin(); it != fgInterposingTuples.end(); it++) {
                                                                                if ( it->replacee == tuple.replacee ) {
                                                                                        tuple.replacee = it->replacement;
@@ -755,6 +870,48 @@ void ImageLoaderMachO::registerInterposing()
        }
 }
 
+uint32_t ImageLoaderMachO::sdkVersion() const
+{
+       const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
+       const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
+       const struct load_command* cmd = cmds;
+       const struct version_min_command* versCmd;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               switch ( cmd->cmd ) {
+                       case LC_VERSION_MIN_MACOSX:
+                       case LC_VERSION_MIN_IPHONEOS:
+                               versCmd = (version_min_command*)cmd;
+                               return versCmd->sdk;
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+       }
+       return 0;
+}
+
+uint32_t ImageLoaderMachO::minOSVersion(const mach_header* mh)
+{
+       const uint32_t cmd_count = mh->ncmds;
+       const struct load_command* const cmds = (struct load_command*)(((char*)mh) + sizeof(macho_header));
+       const struct load_command* cmd = cmds;
+       const struct version_min_command* versCmd;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               switch ( cmd->cmd ) {
+                       case LC_VERSION_MIN_MACOSX:
+                       case LC_VERSION_MIN_IPHONEOS:
+                               versCmd = (version_min_command*)cmd;
+                               return versCmd->version;
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+       }
+       return 0;
+}
+
+uint32_t ImageLoaderMachO::minOSVersion() const
+{
+       return ImageLoaderMachO::minOSVersion(machHeader());
+}
+
+
 void* ImageLoaderMachO::getThreadPC() const
 {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
@@ -794,6 +951,9 @@ void* ImageLoaderMachO::getMain() const
                        #elif __arm__
                                const arm_thread_state_t* registers = (arm_thread_state_t*)(((char*)cmd) + 16);
                                void* entry = (void*)(registers->__pc + fSlide);
+                       #elif __arm64__
+                               const arm_thread_state64_t* registers = (arm_thread_state64_t*)(((char*)cmd) + 16);
+                               void* entry = (void*)(registers->__pc + fSlide);
                        #else
                                #warning need processor specific code
                        #endif
@@ -916,7 +1076,7 @@ void ImageLoaderMachO::getRPaths(const LinkContext& context, std::vector<const c
                        case LC_RPATH:
                                const char* pathToAdd = NULL;
                                const char* path = (char*)cmd + ((struct rpath_command*)cmd)->path.offset;
-                               if ( strncmp(path, "@loader_path/", 13) == 0 ) {
+                               if ( (strncmp(path, "@loader_path", 12) == 0) && ((path[12] == '/') || (path[12] == '\0')) ) {
                                        if ( context.processIsRestricted  && (context.mainExecutable == this) ) {
                                                dyld::warn("LC_RPATH %s in %s being ignored in restricted program because of @loader_path\n", path, this->getPath());
                                                break;
@@ -926,14 +1086,13 @@ void ImageLoaderMachO::getRPaths(const LinkContext& context, std::vector<const c
                                                char newRealPath[strlen(resolvedPath) + strlen(path)];
                                                strcpy(newRealPath, resolvedPath);
                                                char* addPoint = strrchr(newRealPath,'/');
-                                               if ( addPoint != NULL )
-                                                       strcpy(&addPoint[1], &path[13]);
-                                               else
-                                                       strcpy(newRealPath, &path[13]);
-                                               pathToAdd = strdup(newRealPath);
+                                               if ( addPoint != NULL ) {
+                                                       strcpy(addPoint, &path[12]);
+                                                       pathToAdd = strdup(newRealPath);
+                                               }
                                        }
                                }
-                               else if ( strncmp(path, "@executable_path/", 17) == 0 ) {
+                               else if ( (strncmp(path, "@executable_path", 16) == 0) && ((path[16] == '/') || (path[16] == '\0')) ) {
                                        if ( context.processIsRestricted ) {
                                                dyld::warn("LC_RPATH %s in %s being ignored in restricted program because of @executable_path\n", path, this->getPath());
                                                break;
@@ -943,11 +1102,10 @@ void ImageLoaderMachO::getRPaths(const LinkContext& context, std::vector<const c
                                                char newRealPath[strlen(resolvedPath) + strlen(path)];
                                                strcpy(newRealPath, resolvedPath);
                                                char* addPoint = strrchr(newRealPath,'/');
-                                               if ( addPoint != NULL )
-                                                       strcpy(&addPoint[1], &path[17]);
-                                               else
-                                                       strcpy(newRealPath, &path[17]);
-                                               pathToAdd = strdup(newRealPath);
+                                               if ( addPoint != NULL ) {
+                                                       strcpy(addPoint, &path[16]);
+                                                       pathToAdd = strdup(newRealPath);
+                                               }
                                        }
                                }
                                else if ( (path[0] != '/') && context.processIsRestricted ) {
@@ -960,8 +1118,8 @@ void ImageLoaderMachO::getRPaths(const LinkContext& context, std::vector<const c
                                        bool found = false;
                                        for(const char** rp = context.rootPaths; *rp != NULL; ++rp) {
                                                char newPath[PATH_MAX];
-                                               strcpy(newPath, *rp);
-                                               strcat(newPath, path);
+                                               strlcpy(newPath, *rp, PATH_MAX);
+                                               strlcat(newPath, path, PATH_MAX);
                                                struct stat stat_buf;
                                                if ( stat(newPath, &stat_buf) != -1 ) {
                                                        //dyld::log("combined DYLD_ROOT_PATH and LC_RPATH: %s\n", newPath);
@@ -987,6 +1145,7 @@ void ImageLoaderMachO::getRPaths(const LinkContext& context, std::vector<const c
        }
 }
 
+
 bool ImageLoaderMachO::getUUID(uuid_t uuid) const
 {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
@@ -1066,22 +1225,21 @@ void ImageLoaderMachO::doRebase(const LinkContext& context)
 #if TEXT_RELOC_SUPPORT
 void ImageLoaderMachO::makeTextSegmentWritable(const LinkContext& context, bool writeable)
 {
-       int textSegmentIndex = 0;
        for(unsigned int i=0; i < fSegmentsCount; ++i) {
-               if ( strcmp(segName(i), "__TEXT") == 0 ) {
-                       textSegmentIndex = i;
-                       break;
+               if ( segExecutable(i) ) {
+                       if ( writeable ) {
+                               segMakeWritable(i, context);
+                       }
+                       else {
+                       #if !__i386__ && !__x86_64__
+                               // some processors require range to be invalidated before it is made executable
+                               sys_icache_invalidate((void*)segActualLoadAddress(i), segSize(textSegmentIndex));
+                       #endif
+                               segProtect(i, context);
+                       }
                }
        }
 
-       if ( writeable ) {
-               segMakeWritable(textSegmentIndex, context);
-       }
-       else {
-               // iPhoneOS requires range to be invalidated before it is made executable
-               sys_icache_invalidate((void*)segActualLoadAddress(textSegmentIndex), segSize(textSegmentIndex));
-               segProtect(textSegmentIndex, context);
-       }
 }
 #endif
 
@@ -1120,18 +1278,9 @@ uintptr_t ImageLoaderMachO::getExportedSymbolAddress(const Symbol* sym, const Li
 uintptr_t ImageLoaderMachO::getSymbolAddress(const Symbol* sym, const ImageLoader* requestor, 
                                                                                                const LinkContext& context, bool runResolver) const
 {
-       uintptr_t result = exportedSymbolAddress(context, sym, runResolver);
+       uintptr_t result = exportedSymbolAddress(context, sym, requestor, runResolver);
        // check for interposing overrides
-       for (std::vector<InterposeTuple>::iterator it=fgInterposingTuples.begin(); it != fgInterposingTuples.end(); it++) {
-               // replace all references to 'replacee' with 'replacement'
-               if ( (result == it->replacee) && (requestor != it->replacementImage) ) {
-                       if ( context.verboseInterposing ) {
-                               dyld::log("dyld interposing: replace 0x%lX with 0x%lX in %s\n", 
-                                       it->replacee, it->replacement, this->getPath());
-                       }
-                       result = it->replacement;
-               }
-       }
+       result = interposedAddress(context, result, requestor);
        return result;
 }
 
@@ -1270,11 +1419,13 @@ bool ImageLoaderMachO::findSection(const void* imageInterior, const char** segme
 
 
 void __attribute__((noreturn)) ImageLoaderMachO::throwSymbolNotFound(const LinkContext& context, const char* symbol, 
-                                                                                                                                       const char* referencedFrom, const char* expectedIn)
+                                                                                                                                       const char* referencedFrom, const char* fromVersMismatch,
+                                                                                                                                       const char* expectedIn)
 {
        // record values for possible use by CrashReporter or Finder
        (*context.setErrorStrings)(dyld_error_kind_symbol_missing, referencedFrom, expectedIn, symbol);
-       dyld::throwf("Symbol not found: %s\n  Referenced from: %s\n  Expected in: %s\n", symbol, referencedFrom, expectedIn); 
+       dyld::throwf("Symbol not found: %s\n  Referenced from: %s%s\n  Expected in: %s\n",
+                                       symbol, referencedFrom, fromVersMismatch, expectedIn);
 }
 
 const mach_header* ImageLoaderMachO::machHeader() const
@@ -1342,7 +1493,7 @@ uintptr_t ImageLoaderMachO::bindLocation(const LinkContext& context, uintptr_t l
                        break;
                case BIND_TYPE_TEXT_PCREL32:
                        loc32 = (uint32_t*)locationToFix;
-                       value32 = (uint32_t)newValue - (((uintptr_t)locationToFix) + 4);
+                       value32 = (uint32_t)(newValue - (((uintptr_t)locationToFix) + 4));
                        if ( *loc32 != value32 )
                                *loc32 = value32;
                        break;
@@ -1368,7 +1519,7 @@ uintptr_t ImageLoaderMachO::bindLocation(const LinkContext& context, uintptr_t l
 #endif
 
 struct DATAdyld {
-       void*                   dyldLazyBinder;         // filled in at launch by dyld to point into dyld to &stub_binding_helper_interface
+       void*                   dyldLazyBinder;         // filled in at launch by dyld to point into dyld to &stub_binding_helper
        void*                   dyldFuncLookup;         // filled in at launch by dyld to point into dyld to &_dyld_func_lookup
        // the following only exist in main executables built for 10.5 or later
        ProgramVars             vars;
@@ -1376,7 +1527,6 @@ struct DATAdyld {
 
 // These are defined in dyldStartup.s
 extern "C" void stub_binding_helper();
-extern "C" bool dyld_func_lookup(const char* name, uintptr_t* address);
 
 
 void ImageLoaderMachO::setupLazyPointerHandler(const LinkContext& context)
@@ -1399,13 +1549,15 @@ void ImageLoaderMachO::setupLazyPointerHandler(const LinkContext& context)
                                        for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
                                                if ( strcmp(sect->sectname, "__dyld" ) == 0 ) {
                                                        struct DATAdyld* dd = (struct DATAdyld*)(sect->addr + fSlide);
+                               #if !__arm64__
                                                        if ( sect->size > offsetof(DATAdyld, dyldLazyBinder) ) {
                                                                if ( dd->dyldLazyBinder != (void*)&stub_binding_helper )
                                                                        dd->dyldLazyBinder = (void*)&stub_binding_helper;
                                                        }
+                               #endif // !__arm64__
                                                        if ( sect->size > offsetof(DATAdyld, dyldFuncLookup) ) {
-                                                               if ( dd->dyldFuncLookup != (void*)&dyld_func_lookup )
-                                                                       dd->dyldFuncLookup = (void*)&dyld_func_lookup;
+                                                               if ( dd->dyldFuncLookup != (void*)&_dyld_func_lookup )
+                                                                       dd->dyldFuncLookup = (void*)&_dyld_func_lookup;
                                                        }
                                                        if ( mh->filetype == MH_EXECUTE ) {
                                                                // there are two ways to get the program variables
@@ -1526,7 +1678,7 @@ void ImageLoaderMachO::doImageInit(const LinkContext& context)
                                                dyld::throwf("initializer function %p not in mapped image for %s\n", func, this->getPath());
                                        }
                                        if ( context.verboseInit )
-                                               dyld::log("dyld: calling -init function 0x%p in %s\n", func, this->getPath());
+                                               dyld::log("dyld: calling -init function %p in %s\n", func, this->getPath());
                                        func(context.argc, context.argv, context.envp, context.apple, &context.programVars);
                                        break;
                        }
@@ -1550,8 +1702,8 @@ void ImageLoaderMachO::doModInitFunctions(const LinkContext& context)
                                        const uint8_t type = sect->flags & SECTION_TYPE;
                                        if ( type == S_MOD_INIT_FUNC_POINTERS ) {
                                                Initializer* inits = (Initializer*)(sect->addr + fSlide);
-                                               const uint32_t count = sect->size / sizeof(uintptr_t);
-                                               for (uint32_t i=0; i < count; ++i) {
+                                               const size_t count = sect->size / sizeof(uintptr_t);
+                                               for (size_t i=0; i < count; ++i) {
                                                        Initializer func = inits[i];
                                                        // <rdar://problem/8543820&9228031> verify initializers are in image
                                                        if ( ! this->containsAddress((void*)func) ) {
@@ -1646,8 +1798,8 @@ void ImageLoaderMachO::doTermination(const LinkContext& context)
                                        const uint8_t type = sect->flags & SECTION_TYPE;
                                        if ( type == S_MOD_TERM_FUNC_POINTERS ) {
                                                Terminator* terms = (Terminator*)(sect->addr + fSlide);
-                                               const uint32_t count = sect->size / sizeof(uintptr_t);
-                                               for (uint32_t i=count; i > 0; --i) {
+                                               const size_t count = sect->size / sizeof(uintptr_t);
+                                               for (size_t i=count; i > 0; --i) {
                                                        Terminator func = terms[i-1];
                                                        // <rdar://problem/8543820&9228031> verify terminators are in image
                                                        if ( ! this->containsAddress((void*)func) ) {
@@ -1688,7 +1840,13 @@ intptr_t ImageLoaderMachO::assignSegmentAddresses(const LinkContext& context)
                uintptr_t highAddr = 0;
                for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
                        const uintptr_t segLow = segPreferredLoadAddress(i);
-                       const uintptr_t segHigh = (segLow + segSize(i) + 4095) & -4096;
+                       const uintptr_t segHigh = dyld_page_round(segLow + segSize(i));
+                       if ( segLow < highAddr ) {
+                               if ( dyld_page_size > 4096 )
+                                       dyld::throwf("can't map segments into 16KB pages");
+                               else
+                                       dyld::throwf("overlapping segments");
+                       }
                        if ( segLow < lowAddr )
                                lowAddr = segLow;
                        if ( segHigh > highAddr )
@@ -1725,16 +1883,16 @@ uintptr_t ImageLoaderMachO::reserveAnAddressRange(size_t length, const ImageLoad
        // in PIE programs, load initial dylibs after main executable so they don't have fixed addresses either
        if ( fgNextPIEDylibAddress != 0 ) {
                 // add small (0-3 pages) random padding between dylibs
-               addr = fgNextPIEDylibAddress + (__stack_chk_guard/fgNextPIEDylibAddress & (sizeof(long)-1))*4096;
+               addr = fgNextPIEDylibAddress + (__stack_chk_guard/fgNextPIEDylibAddress & (sizeof(long)-1))*dyld_page_size;
                //dyld::log("padding 0x%08llX, guard=0x%08llX\n", (long long)(addr - fgNextPIEDylibAddress), (long long)(__stack_chk_guard));
-               kern_return_t r = vm_allocate(mach_task_self(), &addr, size, VM_FLAGS_FIXED);
+               kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_FIXED | VM_MAKE_TAG(VM_MEMORY_DYLIB));
                if ( r == KERN_SUCCESS ) {
                        fgNextPIEDylibAddress = addr + size;
                        return addr;
                }
                fgNextPIEDylibAddress = 0;
        }
-       kern_return_t r = vm_allocate(mach_task_self(), &addr, size, VM_FLAGS_ANYWHERE);
+       kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_ANYWHERE | VM_MAKE_TAG(VM_MEMORY_DYLIB));
        if ( r != KERN_SUCCESS ) 
                throw "out of address space";
        
@@ -1745,7 +1903,7 @@ bool ImageLoaderMachO::reserveAddressRange(uintptr_t start, size_t length)
 {
        vm_address_t addr = start;
        vm_size_t size = length;
-       kern_return_t r = vm_allocate(mach_task_self(), &addr, size, false /*only this range*/);
+       kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_FIXED | VM_MAKE_TAG(VM_MEMORY_DYLIB));
        if ( r != KERN_SUCCESS ) 
                return false;
        return true;
@@ -1757,8 +1915,12 @@ void ImageLoaderMachO::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInF
 {
        // find address range for image
        intptr_t slide = this->assignSegmentAddresses(context);
-       if ( context.verboseMapping )
-               dyld::log("dyld: Mapping %s\n", this->getPath());
+       if ( context.verboseMapping ) {
+               if ( offsetInFat != 0 )
+                       dyld::log("dyld: Mapping %s (slice offset=%llu)\n", this->getPath(), (unsigned long long)offsetInFat);
+               else
+                       dyld::log("dyld: Mapping %s\n", this->getPath());
+       }
        // map in all segments
        for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
                vm_offset_t fileOffset = segFileOffset(i) + offsetInFat;
@@ -1768,7 +1930,6 @@ void ImageLoaderMachO::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInF
                if ( !segUnaccessible(i) ) {
                        // If has text-relocs, don't set x-bit initially.
                        // Instead set it later after text-relocs have been done.
-                       // The iPhone OS does not like it when you make executable code writable.
                        if ( segExecutable(i) && !(segHasRebaseFixUps(i) && (slide != 0)) )
                                protection   |= PROT_EXEC;
                        if ( segReadable(i) )
@@ -1787,7 +1948,7 @@ void ImageLoaderMachO::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInF
                                dyld::throwf("truncated mach-o error: segment %s extends to %llu which is past end of file %llu", 
                                                                segName(i), (uint64_t)(fileOffset+size), fileLen);
                        }
-                       void* loadAddress = mmap((void*)requestedLoadAddress, size, protection, MAP_FIXED | MAP_PRIVATE, fd, fileOffset);
+                       void* loadAddress = xmmap((void*)requestedLoadAddress, size, protection, MAP_FIXED | MAP_PRIVATE, fd, fileOffset);
                        if ( loadAddress == ((void*)(-1)) ) {
                                dyld::throwf("mmap() error %d at address=0x%08lX, size=0x%08lX segment=%s in Segment::map() mapping %s", 
                                        errno, requestedLoadAddress, (uintptr_t)size, segName(i), getPath());