libkern/kxld/kxld_splitinfolc.c

   1 /*
   2  * Copyright (c) 2016 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <string.h>
  29 #include <mach-o/loader.h>
  30 #include <sys/types.h>
  31
  32 #define DEBUG_ASSERT_COMPONENT_NAME_STRING "kxld"
  33 #include <AssertMacros.h>
  34
  35 #include "kxld_util.h"
  36 #include "kxld_splitinfolc.h"
  37
  38 /*******************************************************************************
  39  *******************************************************************************/
  40 void
  41 kxld_splitinfolc_init_from_macho(KXLDsplitinfolc *splitinfolc, struct linkedit_data_command *src)
  42 {
  43     check(splitinfolc);
  44     check(src);
  45
  46     splitinfolc->cmdsize = src->cmdsize;
  47     splitinfolc->dataoff = src->dataoff;
  48     splitinfolc->datasize = src->datasize;
  49     splitinfolc->has_splitinfolc = TRUE;
  50 }
  51
  52 /*******************************************************************************
  53  *******************************************************************************/
  54 void
  55 kxld_splitinfolc_clear(KXLDsplitinfolc *splitinfolc)
  56 {
  57     bzero(splitinfolc, sizeof(*splitinfolc));
  58 }
  59
  60 /*******************************************************************************
  61  *******************************************************************************/
  62 u_long
  63 kxld_splitinfolc_get_macho_header_size(void)
  64 {
  65     return sizeof(struct linkedit_data_command);
  66 }
  67
  68 /*******************************************************************************
  69  *******************************************************************************/
  70 kern_return_t
  71 kxld_splitinfolc_export_macho(const KXLDsplitinfolc *splitinfolc,
  72                               splitKextLinkInfo *linked_object,
  73                               u_long *header_offset,
  74                               u_long header_size,
  75                               u_long *data_offset,
  76                               u_long size)
  77 {
  78         kern_return_t       rval = KERN_FAILURE;
  79         struct linkedit_data_command *splitinfolc_hdr = NULL;
  80         u_char *            buf;
  81
  82         check(splitinfolc);
  83         check(linked_object);
  84         check(header_offset);
  85         check(data_offset);
  86
  87         buf = (u_char *)(linked_object->linkedKext);
  88         require_action(sizeof(*splitinfolc_hdr) <= header_size - *header_offset,
  89                        finish,
  90                        rval=KERN_FAILURE);
  91         splitinfolc_hdr = (struct linkedit_data_command *)((void *)(buf + *header_offset));
  92         *header_offset += sizeof(*splitinfolc_hdr);
  93
  94     if (buf + *data_offset > buf + size) {
  95         kxld_log(kKxldLogLinking, kKxldLogErr,
  96                  "\n OVERFLOW! linkedKext %p to %p (%lu) copy %p to %p (%u) <%s>",
  97                  (void *) buf,
  98                  (void *) (buf + size),
  99                  size,
 100                  (void *) (buf + *data_offset),
 101                  (void *) (buf + *data_offset + splitinfolc->datasize),
 102                  splitinfolc->datasize,
 103                 __func__);
 104         goto finish;
 105     }
 106
 107         // copy in the split info reloc data from kextExecutable. For example dataoff
 108         // in LC_SEGMENT_SPLIT_INFO load command points to the reloc data in the
 109         // __LINKEDIT segment.  In this case 65768 into the kextExecutable file is
 110         // the split seg reloc info (for 920 bytes)
 111 //    Load command 9
 112 //    cmd LC_SEGMENT_SPLIT_INFO
 113 //    cmdsize 16
 114 //    dataoff 65768
 115 //    datasize 920
 116
 117
 118         memcpy(buf + *data_offset, linked_object->kextExecutable + splitinfolc->dataoff, splitinfolc->datasize);
 119
 120 #if SPLIT_KEXTS_DEBUG
 121     u_char *dataPtr = buf + *data_offset;
 122
 123     kxld_log(kKxldLogLinking, kKxldLogErr,
 124              "\n\n linkedKext %p to %p (%lu) copy %p to %p (%u) <%s>",
 125              (void *) buf,
 126              (void *) (buf + size),
 127              size,
 128              (void *) (dataPtr),
 129              (void *) (dataPtr + splitinfolc->datasize),
 130              splitinfolc->datasize,
 131              __func__);
 132
 133     if (*(dataPtr + 0) != 0x7F) {
 134         kxld_log(kKxldLogLinking, kKxldLogErr,
 135                  "\n\n bad LC_SEGMENT_SPLIT_INFO: 0x%02X %02X %02X %02X %02X %02X %02X %02X at %p (buf %p + %lu) <%s>",
 136                  *(dataPtr +0),
 137                  *(dataPtr +1),
 138                  *(dataPtr +2),
 139                  *(dataPtr +3),
 140                  *(dataPtr +4),
 141                  *(dataPtr +5),
 142                  *(dataPtr +6),
 143                  *(dataPtr +7),
 144                  (void *) dataPtr,
 145                  (void *) buf,
 146                  *data_offset, __func__);
 147     }
 148 #endif
 149
 150         // update the load command header
 151         splitinfolc_hdr->cmd = LC_SEGMENT_SPLIT_INFO;
 152         splitinfolc_hdr->cmdsize = (uint32_t) sizeof(*splitinfolc_hdr);
 153         splitinfolc_hdr->dataoff = (uint32_t)(*data_offset);
 154         splitinfolc_hdr->datasize = splitinfolc->datasize;
 155
 156         *data_offset += splitinfolc->datasize;
 157
 158         rval = KERN_SUCCESS;
 159
 160 finish:
 161         return rval;
 162 }
 163