external/bsd/elftoolchain/dist/libelf/libelf_ehdr.c

   1 /*      $NetBSD: libelf_ehdr.c,v 1.2 2014/03/09 16:58:04 christos Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2006,2008 Joseph Koshy
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #if HAVE_NBTOOL_CONFIG_H
  30 # include "nbtool_config.h"
  31 #endif
  32
  33 #include <sys/cdefs.h>
  34
  35 #include <assert.h>
  36 #include <gelf.h>
  37 #include <libelf.h>
  38 #include <stdlib.h>
  39
  40 #include "_libelf.h"
  41
  42 __RCSID("$NetBSD: libelf_ehdr.c,v 1.2 2014/03/09 16:58:04 christos Exp $");
  43 ELFTC_VCSID("Id: libelf_ehdr.c 2225 2011-11-26 18:55:54Z jkoshy ");
  44
  45 /*
  46  * Retrieve counts for sections, phdrs and the section string table index
  47  * from section header #0 of the ELF object.
  48  */
  49 static int
  50 _libelf_load_extended(Elf *e, int ec, uint64_t shoff, uint16_t phnum,
  51     uint16_t strndx)
  52 {
  53         Elf_Scn *scn;
  54         size_t fsz;
  55         int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
  56         uint32_t shtype;
  57
  58         assert(STAILQ_EMPTY(&e->e_u.e_elf.e_scn));
  59
  60         fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, 1);
  61         assert(fsz > 0);
  62
  63         if (e->e_rawsize < shoff + fsz) { /* raw file too small */
  64                 LIBELF_SET_ERROR(HEADER, 0);
  65                 return (0);
  66         }
  67
  68         if ((scn = _libelf_allocate_scn(e, (size_t) 0)) == NULL)
  69                 return (0);
  70
  71         if (shoff > SSIZE_MAX) {
  72                 LIBELF_SET_ERROR(HEADER, 0);
  73                 return (0);
  74         }
  75
  76         xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec);
  77         (*xlator)((void *) &scn->s_shdr, sizeof(scn->s_shdr),
  78             e->e_rawfile + shoff, (size_t) 1,
  79             e->e_byteorder != _libelf_host_byteorder());
  80
  81 #define GET_SHDR_MEMBER(M) ((ec == ELFCLASS32) ? scn->s_shdr.s_shdr32.M : \
  82                 scn->s_shdr.s_shdr64.M)
  83
  84         if (GET_SHDR_MEMBER(sh_size) > UINT_MAX) {
  85                 LIBELF_SET_ERROR(HEADER, 0);
  86                 return (0);
  87         }
  88
  89         if ((shtype = GET_SHDR_MEMBER(sh_type)) != SHT_NULL) {
  90                 LIBELF_SET_ERROR(SECTION, 0);
  91                 return (0);
  92         }
  93
  94         e->e_u.e_elf.e_nscn = (unsigned int)GET_SHDR_MEMBER(sh_size);
  95         e->e_u.e_elf.e_nphdr = (phnum != PN_XNUM) ? phnum :
  96             GET_SHDR_MEMBER(sh_info);
  97         e->e_u.e_elf.e_strndx = (strndx != SHN_XINDEX) ? strndx :
  98             GET_SHDR_MEMBER(sh_link);
  99 #undef  GET_SHDR_MEMBER
 100
 101         return (1);
 102 }
 103
 104 #define EHDR_INIT(E,SZ)  do {                                           \
 105                 Elf##SZ##_Ehdr *eh = (E);                               \
 106                 eh->e_ident[EI_MAG0] = ELFMAG0;                         \
 107                 eh->e_ident[EI_MAG1] = ELFMAG1;                         \
 108                 eh->e_ident[EI_MAG2] = ELFMAG2;                         \
 109                 eh->e_ident[EI_MAG3] = ELFMAG3;                         \
 110                 eh->e_ident[EI_CLASS] = ELFCLASS##SZ;                   \
 111                 eh->e_ident[EI_DATA]  = ELFDATANONE;                    \
 112                 eh->e_ident[EI_VERSION] = LIBELF_PRIVATE(version);      \
 113                 eh->e_machine = EM_NONE;                                \
 114                 eh->e_type    = ELF_K_NONE;                             \
 115                 eh->e_version = LIBELF_PRIVATE(version);                \
 116         } while (/*CONSTCOND*/0)
 117
 118 void *
 119 _libelf_ehdr(Elf *e, int ec, int allocate)
 120 {
 121         void *ehdr;
 122         size_t fsz, msz;
 123         uint16_t phnum, shnum, strndx;
 124         uint64_t shoff;
 125         int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
 126
 127         assert(ec == ELFCLASS32 || ec == ELFCLASS64);
 128
 129         if (e == NULL || e->e_kind != ELF_K_ELF) {
 130                 LIBELF_SET_ERROR(ARGUMENT, 0);
 131                 return (NULL);
 132         }
 133
 134         if (e->e_class != ELFCLASSNONE && e->e_class != ec) {
 135                 LIBELF_SET_ERROR(CLASS, 0);
 136                 return (NULL);
 137         }
 138
 139         if (e->e_version != EV_CURRENT) {
 140                 LIBELF_SET_ERROR(VERSION, 0);
 141                 return (NULL);
 142         }
 143
 144         if (e->e_class == ELFCLASSNONE)
 145                 e->e_class = ec;
 146
 147         if (ec == ELFCLASS32)
 148                 ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr32;
 149         else
 150                 ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr64;
 151
 152         if (ehdr != NULL)       /* already have a translated ehdr */
 153                 return (ehdr);
 154
 155         fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1);
 156         assert(fsz > 0);
 157
 158         if (e->e_cmd != ELF_C_WRITE && e->e_rawsize < fsz) {
 159                 LIBELF_SET_ERROR(HEADER, 0);
 160                 return (NULL);
 161         }
 162
 163         msz = _libelf_msize(ELF_T_EHDR, ec, EV_CURRENT);
 164
 165         assert(msz > 0);
 166
 167         if ((ehdr = calloc((size_t) 1, msz)) == NULL) {
 168                 LIBELF_SET_ERROR(RESOURCE, 0);
 169                 return (NULL);
 170         }
 171
 172         if (ec == ELFCLASS32) {
 173                 e->e_u.e_elf.e_ehdr.e_ehdr32 = ehdr;
 174                 EHDR_INIT(ehdr,32);
 175         } else {
 176                 e->e_u.e_elf.e_ehdr.e_ehdr64 = ehdr;
 177                 EHDR_INIT(ehdr,64);
 178         }
 179
 180         if (allocate)
 181                 e->e_flags |= ELF_F_DIRTY;
 182
 183         if (e->e_cmd == ELF_C_WRITE)
 184                 return (ehdr);
 185
 186         xlator = _libelf_get_translator(ELF_T_EHDR, ELF_TOMEMORY, ec);
 187         (*xlator)(ehdr, msz, e->e_rawfile, (size_t) 1,
 188             e->e_byteorder != _libelf_host_byteorder());
 189
 190         /*
 191          * If extended numbering is being used, read the correct
 192          * number of sections and program header entries.
 193          */
 194         if (ec == ELFCLASS32) {
 195                 phnum = ((Elf32_Ehdr *) ehdr)->e_phnum;
 196                 shnum = ((Elf32_Ehdr *) ehdr)->e_shnum;
 197                 shoff = ((Elf32_Ehdr *) ehdr)->e_shoff;
 198                 strndx = ((Elf32_Ehdr *) ehdr)->e_shstrndx;
 199         } else {
 200                 phnum = ((Elf64_Ehdr *) ehdr)->e_phnum;
 201                 shnum = ((Elf64_Ehdr *) ehdr)->e_shnum;
 202                 shoff = ((Elf64_Ehdr *) ehdr)->e_shoff;
 203                 strndx = ((Elf64_Ehdr *) ehdr)->e_shstrndx;
 204         }
 205
 206         if (shnum >= SHN_LORESERVE ||
 207             (shoff == 0LL && (shnum != 0 || phnum == PN_XNUM ||
 208                 strndx == SHN_XINDEX))) {
 209                 LIBELF_SET_ERROR(HEADER, 0);
 210                 return (NULL);
 211         }
 212
 213         if (shnum != 0 || shoff == 0LL) { /* not using extended numbering */
 214                 e->e_u.e_elf.e_nphdr = phnum;
 215                 e->e_u.e_elf.e_nscn = shnum;
 216                 e->e_u.e_elf.e_strndx = strndx;
 217         } else if (_libelf_load_extended(e, ec, shoff, phnum, strndx) == 0)
 218                 return (NULL);
 219
 220         return (ehdr);
 221 }