]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/mach_fat.c
xnu-3789.1.32.tar.gz
[apple/xnu.git] / bsd / kern / mach_fat.c
index 677ae0008abd65bcfcd08e9aad5ce6b11de60935..7af7c658083565abbda12f2d14e047bdbfa78d06 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1991-2015 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  * 
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
-/* Copyright (c) 1991 NeXT Computer, Inc.  All rights reserved.
- *
- *     File:   kern/mach_fat.c
- *     Author: Peter King
- *
- *     Fat file support routines.
- *
- */
-
 #include <sys/param.h>
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <kern/cpu_number.h>
 #include <mach-o/fat.h>
 #include <kern/mach_loader.h>
+#include <kern/mach_fat.h>
 #include <libkern/OSByteOrder.h>
 #include <machine/exec.h>
 
 /**********************************************************************
- * Routine:    fatfile_getarch2()
+ * Routine:    fatfile_getarch()
  *
  * Function:   Locate the architecture-dependant contents of a fat
  *             file that match this CPU.
  *
- * Args:       vp:             The vnode for the fat file.
- *             header:         A pointer to the fat file header.
+ * Args: header:               A pointer to the fat file header.
+ *             size:                   How large the fat file header is (including fat_arch array)
  *             req_cpu_type:   The required cpu type.
  *             mask_bits:      Bits to mask from the sub-image type when
  *                             grading it vs. the req_cpu_type
  *             KERN_FAILURE:   No valid architecture found.
  **********************************************************************/
 static load_return_t
-fatfile_getarch2(
-#if 0
-       struct vnode    *vp,
-#else
-       __unused struct vnode   *vp,
-#endif
+fatfile_getarch(
        vm_offset_t     data_ptr,
+       vm_size_t       data_size,
        cpu_type_t      req_cpu_type,
        cpu_type_t      mask_bits,
        struct fat_arch *archret)
 {
-       /* vm_pager_t           pager; */
-       vm_offset_t             addr;
-       vm_size_t               size;
        load_return_t           lret;
        struct fat_arch         *arch;
        struct fat_arch         *best_arch;
        int                     grade;
        int                     best_grade;
-       int                     nfat_arch;
-       off_t           end_of_archs;
+       uint32_t                nfat_arch, max_nfat_arch;
+       cpu_type_t              testtype;
+       cpu_type_t              testsubtype;
        struct fat_header       *header;
-#if 0
-       off_t filesize;
-#endif
 
-       /*
-        *      Get the pager for the file.
-        */
+       if (sizeof(struct fat_header) > data_size) {
+               return (LOAD_FAILURE);
+       }
 
        header = (struct fat_header *)data_ptr;
-
-       /*
-        *      Map portion that must be accessible directly into
-        *      kernel's map.
-        */
        nfat_arch = OSSwapBigToHostInt32(header->nfat_arch);
 
-       end_of_archs = (off_t)nfat_arch * sizeof(struct fat_arch) + 
-               sizeof(struct fat_header);
-#if 0
-       filesize = ubc_getsize(vp);
-       if (end_of_archs > (int)filesize) {
-               return(LOAD_BADMACHO);
+       max_nfat_arch = (data_size - sizeof(struct fat_header)) / sizeof(struct fat_arch);
+       if (nfat_arch > max_nfat_arch) {
+               /* nfat_arch would cause us to read off end of buffer */
+               return (LOAD_BADMACHO);
        }
-#endif
-
-       /*
-        * This check is limited on the top end because we are reading
-        * only PAGE_SIZE bytes
-        */
-       if (end_of_archs > PAGE_SIZE ||
-               end_of_archs < (sizeof(struct fat_header)+sizeof(struct fat_arch)))
-               return(LOAD_BADMACHO);
-
-       /*
-        *      Round size of fat_arch structures up to page boundry.
-        */
-       size = round_page_32(end_of_archs);
-       if (size == 0)
-               return(LOAD_BADMACHO);
 
        /*
-        * Scan the fat_arch's looking for the best one.
-        */
-       addr = data_ptr;
+        * Scan the fat_arch's looking for the best one.  */
        best_arch = NULL;
        best_grade = 0;
-       arch = (struct fat_arch *) (addr + sizeof(struct fat_header));
+       arch = (struct fat_arch *) (data_ptr + sizeof(struct fat_header));
        for (; nfat_arch-- > 0; arch++) {
+               testtype = OSSwapBigToHostInt32(arch->cputype);
+               testsubtype = OSSwapBigToHostInt32(arch->cpusubtype) & ~CPU_SUBTYPE_MASK;
 
                /*
                 *      Check to see if right cpu type.
                 */
-               if(((cpu_type_t)OSSwapBigToHostInt32(arch->cputype) & ~mask_bits) != req_cpu_type)
+               if((testtype & ~mask_bits) != (req_cpu_type & ~mask_bits)) {
                        continue;
+               }
 
                /*
-                *      Get the grade of the cpu subtype.
+                *      Get the grade of the cpu subtype (without feature flags)
                 */
-               grade = grade_binary(
-                           OSSwapBigToHostInt32(arch->cputype),
-                           OSSwapBigToHostInt32(arch->cpusubtype));
+               grade = grade_binary(testtype, testsubtype);
 
                /*
                 *      Remember it if it's the best we've seen.
@@ -185,56 +144,29 @@ fatfile_getarch2(
 }
 
 load_return_t
-fatfile_getarch_affinity(
-               struct vnode            *vp,
+fatfile_getbestarch(
                vm_offset_t             data_ptr,
-               struct fat_arch *archret,
-               int                             affinity)
+               vm_size_t               data_size,
+               struct fat_arch *archret)
 {
-               load_return_t lret;
-               int handler = (exec_archhandler_ppc.path[0] != 0);
-               cpu_type_t primary_type, fallback_type;
-
-               if (handler && affinity) {
-                               primary_type = CPU_TYPE_POWERPC;
-                               fallback_type = cpu_type();
-               } else {
-                               primary_type = cpu_type();
-                               fallback_type = CPU_TYPE_POWERPC;
-               }
-               /*
-                * Ignore the architectural bits when determining if an image
-                * in a fat file should be skipped or graded.
-                */
-               lret = fatfile_getarch2(vp, data_ptr, primary_type, CPU_ARCH_MASK, archret);
-               if ((lret != 0) && handler) {
-                       lret = fatfile_getarch2(vp, data_ptr, fallback_type,
-                                               0, archret);
-               }
-               return lret;
+       /*
+        * Ignore all architectural bits when determining if an image
+        * in a fat file should be skipped or graded.
+        */
+       return fatfile_getarch(data_ptr, data_size, cpu_type(), CPU_ARCH_MASK, archret);
 }
 
-/**********************************************************************
- * Routine:    fatfile_getarch()
- *
- * Function:   Locate the architecture-dependant contents of a fat
- *             file that match this CPU.
- *
- * Args:       vp:             The vnode for the fat file.
- *             header:         A pointer to the fat file header.
- *             archret (out):  Pointer to fat_arch structure to hold
- *                             the results.
- *
- * Returns:    KERN_SUCCESS:   Valid architecture found.
- *             KERN_FAILURE:   No valid architecture found.
- **********************************************************************/
 load_return_t
-fatfile_getarch(
-       struct vnode            *vp,
-       vm_offset_t     data_ptr,
-       struct fat_arch         *archret)
+fatfile_getbestarch_for_cputype(
+       cpu_type_t cputype,
+       vm_offset_t data_ptr,
+       vm_size_t data_size,
+       struct fat_arch *archret)
 {
-       return fatfile_getarch2(vp, data_ptr, cpu_type(), 0, archret);
+       /*
+        * Scan the fat_arch array for exact matches for this cpu_type_t only
+        */
+       return fatfile_getarch(data_ptr, data_size, cputype, 0, archret);
 }
 
 /**********************************************************************
@@ -254,11 +186,111 @@ fatfile_getarch(
  **********************************************************************/
 load_return_t
 fatfile_getarch_with_bits(
-       struct vnode            *vp,
        integer_t               archbits,
        vm_offset_t     data_ptr,
+       vm_size_t               data_size,
        struct fat_arch         *archret)
 {
-       return fatfile_getarch2(vp, data_ptr, archbits | cpu_type(), 0, archret);
+       /*
+        * Scan the fat_arch array for matches with the requested
+        * architectural bits set, and for the current hardware cpu CPU.
+        */
+       return fatfile_getarch(data_ptr, data_size, (archbits & CPU_ARCH_MASK) | (cpu_type() & ~CPU_ARCH_MASK), 0, archret);
 }
 
+/*
+ * Validate the fat_header and fat_arch array in memory. We check that:
+ *
+ * 1) arch count would not exceed the data buffer
+ * 2) arch list does not contain duplicate cputype/cpusubtype tuples
+ * 3) arch list does not have two overlapping slices. The area
+ *    at the front of the file containing the fat headers is implicitly
+ *    a range that a slice should also not try to cover
+ */
+load_return_t
+fatfile_validate_fatarches(vm_offset_t data_ptr, vm_size_t data_size)
+{
+       uint32_t magic, nfat_arch;
+       uint32_t max_nfat_arch, i, j;
+       uint32_t fat_header_size;
+
+       struct fat_arch         *arches;
+       struct fat_header       *header;
+
+       if (sizeof(struct fat_header) > data_size) {
+               return (LOAD_FAILURE);
+       }
+
+       header = (struct fat_header *)data_ptr;
+       magic = OSSwapBigToHostInt32(header->magic);
+       nfat_arch = OSSwapBigToHostInt32(header->nfat_arch);
+
+       if (magic != FAT_MAGIC) {
+               /* must be FAT_MAGIC big endian */
+               return (LOAD_FAILURE);
+       }
+
+       max_nfat_arch = (data_size - sizeof(struct fat_header)) / sizeof(struct fat_arch);
+       if (nfat_arch > max_nfat_arch) {
+               /* nfat_arch would cause us to read off end of buffer */
+               return (LOAD_BADMACHO);
+       }
+
+       /* now that we know the fat_arch list fits in the buffer, how much does it use? */
+       fat_header_size = sizeof(struct fat_header) + nfat_arch * sizeof(struct fat_arch);
+       arches = (struct fat_arch *)(data_ptr + sizeof(struct fat_header));
+
+       for (i=0; i < nfat_arch; i++) {
+               uint32_t i_begin = OSSwapBigToHostInt32(arches[i].offset);
+               uint32_t i_size = OSSwapBigToHostInt32(arches[i].size);
+               uint32_t i_cputype = OSSwapBigToHostInt32(arches[i].cputype);
+               uint32_t i_cpusubtype = OSSwapBigToHostInt32(arches[i].cpusubtype);
+
+               if (i_begin < fat_header_size) {
+                       /* slice is trying to claim part of the file used by fat headers themselves */
+                       return (LOAD_BADMACHO);
+               }
+
+               if ((UINT32_MAX - i_size) < i_begin) {
+                       /* start + size would overflow */
+                       return (LOAD_BADMACHO);
+               }
+               uint32_t i_end = i_begin + i_size;
+
+               for (j=i+1; j < nfat_arch; j++) {
+                       uint32_t j_begin = OSSwapBigToHostInt32(arches[j].offset);
+                       uint32_t j_size = OSSwapBigToHostInt32(arches[j].size);
+                       uint32_t j_cputype = OSSwapBigToHostInt32(arches[j].cputype);
+                       uint32_t j_cpusubtype = OSSwapBigToHostInt32(arches[j].cpusubtype);
+
+                       if ((i_cputype == j_cputype) && (i_cpusubtype == j_cpusubtype)) {
+                               /* duplicate cputype/cpusubtype, results in ambiguous references */
+                               return (LOAD_BADMACHO);
+                       }
+
+                       if ((UINT32_MAX - j_size) < j_begin) {
+                               /* start + size would overflow */
+                               return (LOAD_BADMACHO);
+                       }
+                       uint32_t j_end = j_begin + j_size;
+
+                       if (i_begin <= j_begin) {
+                               if (i_end <= j_begin) {
+                                       /* I completely precedes J */
+                               } else {
+                                       /* I started before J, but ends somewhere in or after J */
+                                       return (LOAD_BADMACHO);
+                               }
+                       } else {
+                               if (i_begin >= j_end) {
+                                       /* I started after J started but also after J ended */
+                               } else {
+                                       /* I started after J started but before it ended, so there is overlap */
+                                       return (LOAD_BADMACHO);
+                               }
+                       }
+               }
+       }
+
+       return (LOAD_SUCCESS);
+}