1164190Sjkoshy/*- 2164190Sjkoshy * Copyright (c) 2006 Joseph Koshy 3164190Sjkoshy * All rights reserved. 4164190Sjkoshy * 5164190Sjkoshy * Redistribution and use in source and binary forms, with or without 6164190Sjkoshy * modification, are permitted provided that the following conditions 7164190Sjkoshy * are met: 8164190Sjkoshy * 1. Redistributions of source code must retain the above copyright 9164190Sjkoshy * notice, this list of conditions and the following disclaimer. 10164190Sjkoshy * 2. Redistributions in binary form must reproduce the above copyright 11164190Sjkoshy * notice, this list of conditions and the following disclaimer in the 12164190Sjkoshy * documentation and/or other materials provided with the distribution. 13164190Sjkoshy * 14164190Sjkoshy * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15164190Sjkoshy * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16164190Sjkoshy * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17164190Sjkoshy * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18164190Sjkoshy * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19164190Sjkoshy * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20164190Sjkoshy * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21164190Sjkoshy * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22164190Sjkoshy * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23164190Sjkoshy * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24164190Sjkoshy * SUCH DAMAGE. 25164190Sjkoshy * 26164190Sjkoshy * $FreeBSD$ 27164190Sjkoshy */ 28164190Sjkoshy 29164190Sjkoshy#include <sys/cdefs.h> 30164190Sjkoshy__FBSDID("$FreeBSD$"); 31164190Sjkoshy 32164190Sjkoshy#include <assert.h> 33164190Sjkoshy#include <gelf.h> 34164190Sjkoshy#include <libelf.h> 35164190Sjkoshy#include <stdlib.h> 36164190Sjkoshy 37164190Sjkoshy#include "_libelf.h" 38164190Sjkoshy 39165535Sjkoshy/* 40165535Sjkoshy * Retrieve counts for sections, phdrs and the section string table index 41165535Sjkoshy * from section header #0 of the ELF object. 42165535Sjkoshy */ 43165535Sjkoshystatic int 44165535Sjkoshy_libelf_load_extended(Elf *e, int ec, uint64_t shoff, uint16_t phnum, 45165535Sjkoshy uint16_t strndx) 46165535Sjkoshy{ 47165535Sjkoshy Elf_Scn *scn; 48165535Sjkoshy size_t fsz; 49210338Skaiw int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap); 50165535Sjkoshy uint32_t shtype; 51165535Sjkoshy 52165535Sjkoshy assert(STAILQ_EMPTY(&e->e_u.e_elf.e_scn)); 53165535Sjkoshy 54165535Sjkoshy fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, 1); 55165535Sjkoshy assert(fsz > 0); 56165535Sjkoshy 57165535Sjkoshy if (e->e_rawsize < shoff + fsz) { /* raw file too small */ 58165535Sjkoshy LIBELF_SET_ERROR(HEADER, 0); 59165535Sjkoshy return (0); 60165535Sjkoshy } 61165535Sjkoshy 62165535Sjkoshy if ((scn = _libelf_allocate_scn(e, (size_t) 0)) == NULL) 63165535Sjkoshy return (0); 64165535Sjkoshy 65165535Sjkoshy xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); 66210338Skaiw (*xlator)((char *) &scn->s_shdr, sizeof(scn->s_shdr), 67210338Skaiw e->e_rawfile + shoff, (size_t) 1, 68165535Sjkoshy e->e_byteorder != LIBELF_PRIVATE(byteorder)); 69165535Sjkoshy 70165535Sjkoshy#define GET_SHDR_MEMBER(M) ((ec == ELFCLASS32) ? scn->s_shdr.s_shdr32.M : \ 71165535Sjkoshy scn->s_shdr.s_shdr64.M) 72165535Sjkoshy 73165535Sjkoshy if ((shtype = GET_SHDR_MEMBER(sh_type)) != SHT_NULL) { 74165535Sjkoshy LIBELF_SET_ERROR(SECTION, 0); 75165535Sjkoshy return (0); 76165535Sjkoshy } 77165535Sjkoshy 78165535Sjkoshy e->e_u.e_elf.e_nscn = GET_SHDR_MEMBER(sh_size); 79165535Sjkoshy e->e_u.e_elf.e_nphdr = (phnum != PN_XNUM) ? phnum : 80165535Sjkoshy GET_SHDR_MEMBER(sh_info); 81165535Sjkoshy e->e_u.e_elf.e_strndx = (strndx != SHN_XINDEX) ? strndx : 82165535Sjkoshy GET_SHDR_MEMBER(sh_link); 83165535Sjkoshy#undef GET_SHDR_MEMBER 84165535Sjkoshy 85165535Sjkoshy return (1); 86165535Sjkoshy} 87165535Sjkoshy 88164190Sjkoshy#define EHDR_INIT(E,SZ) do { \ 89164190Sjkoshy Elf##SZ##_Ehdr *eh = (E); \ 90164190Sjkoshy eh->e_ident[EI_MAG0] = ELFMAG0; \ 91164190Sjkoshy eh->e_ident[EI_MAG1] = ELFMAG1; \ 92164190Sjkoshy eh->e_ident[EI_MAG2] = ELFMAG2; \ 93164190Sjkoshy eh->e_ident[EI_MAG3] = ELFMAG3; \ 94164190Sjkoshy eh->e_ident[EI_CLASS] = ELFCLASS##SZ; \ 95164190Sjkoshy eh->e_ident[EI_DATA] = ELFDATANONE; \ 96164190Sjkoshy eh->e_ident[EI_VERSION] = LIBELF_PRIVATE(version); \ 97164190Sjkoshy eh->e_machine = EM_NONE; \ 98164190Sjkoshy eh->e_type = ELF_K_NONE; \ 99164190Sjkoshy eh->e_version = LIBELF_PRIVATE(version); \ 100164190Sjkoshy } while (0) 101164190Sjkoshy 102164190Sjkoshyvoid * 103164190Sjkoshy_libelf_ehdr(Elf *e, int ec, int allocate) 104164190Sjkoshy{ 105165535Sjkoshy void *ehdr; 106164190Sjkoshy size_t fsz, msz; 107165535Sjkoshy uint16_t phnum, shnum, strndx; 108165535Sjkoshy uint64_t shoff; 109210338Skaiw int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap); 110164190Sjkoshy 111164190Sjkoshy assert(ec == ELFCLASS32 || ec == ELFCLASS64); 112164190Sjkoshy 113164190Sjkoshy if (e == NULL || e->e_kind != ELF_K_ELF) { 114164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 115164190Sjkoshy return (NULL); 116164190Sjkoshy } 117164190Sjkoshy 118164190Sjkoshy if (e->e_class != ELFCLASSNONE && e->e_class != ec) { 119164190Sjkoshy LIBELF_SET_ERROR(CLASS, 0); 120164190Sjkoshy return (NULL); 121164190Sjkoshy } 122164190Sjkoshy 123164190Sjkoshy if (e->e_version != EV_CURRENT) { 124164190Sjkoshy LIBELF_SET_ERROR(VERSION, 0); 125164190Sjkoshy return (NULL); 126164190Sjkoshy } 127164190Sjkoshy 128164190Sjkoshy if (e->e_class == ELFCLASSNONE) 129164190Sjkoshy e->e_class = ec; 130164190Sjkoshy 131164190Sjkoshy if (ec == ELFCLASS32) 132164190Sjkoshy ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr32; 133164190Sjkoshy else 134164190Sjkoshy ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr64; 135164190Sjkoshy 136164190Sjkoshy if (ehdr != NULL) /* already have a translated ehdr */ 137164190Sjkoshy return (ehdr); 138164190Sjkoshy 139165535Sjkoshy fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1); 140164190Sjkoshy assert(fsz > 0); 141164190Sjkoshy 142164190Sjkoshy if (e->e_cmd != ELF_C_WRITE && e->e_rawsize < fsz) { 143164190Sjkoshy LIBELF_SET_ERROR(HEADER, 0); 144164190Sjkoshy return (NULL); 145164190Sjkoshy } 146164190Sjkoshy 147164190Sjkoshy msz = _libelf_msize(ELF_T_EHDR, ec, EV_CURRENT); 148164190Sjkoshy 149164190Sjkoshy assert(msz > 0); 150164190Sjkoshy 151164190Sjkoshy if ((ehdr = calloc((size_t) 1, msz)) == NULL) { 152164190Sjkoshy LIBELF_SET_ERROR(RESOURCE, 0); 153164190Sjkoshy return (NULL); 154164190Sjkoshy } 155164190Sjkoshy 156164190Sjkoshy if (ec == ELFCLASS32) { 157164190Sjkoshy e->e_u.e_elf.e_ehdr.e_ehdr32 = ehdr; 158164190Sjkoshy EHDR_INIT(ehdr,32); 159164190Sjkoshy } else { 160164190Sjkoshy e->e_u.e_elf.e_ehdr.e_ehdr64 = ehdr; 161164190Sjkoshy EHDR_INIT(ehdr,64); 162164190Sjkoshy } 163164190Sjkoshy 164164190Sjkoshy if (allocate) 165164190Sjkoshy e->e_flags |= ELF_F_DIRTY; 166164190Sjkoshy 167164190Sjkoshy if (e->e_cmd == ELF_C_WRITE) 168164190Sjkoshy return (ehdr); 169164190Sjkoshy 170164190Sjkoshy xlator = _libelf_get_translator(ELF_T_EHDR, ELF_TOMEMORY, ec); 171210338Skaiw (*xlator)(ehdr, msz, e->e_rawfile, (size_t) 1, 172164190Sjkoshy e->e_byteorder != LIBELF_PRIVATE(byteorder)); 173164190Sjkoshy 174165535Sjkoshy /* 175165535Sjkoshy * If extended numbering is being used, read the correct 176165535Sjkoshy * number of sections and program header entries. 177165535Sjkoshy */ 178165535Sjkoshy if (ec == ELFCLASS32) { 179165535Sjkoshy phnum = ((Elf32_Ehdr *) ehdr)->e_phnum; 180165535Sjkoshy shnum = ((Elf32_Ehdr *) ehdr)->e_shnum; 181165535Sjkoshy shoff = ((Elf32_Ehdr *) ehdr)->e_shoff; 182165535Sjkoshy strndx = ((Elf32_Ehdr *) ehdr)->e_shstrndx; 183165535Sjkoshy } else { 184165535Sjkoshy phnum = ((Elf64_Ehdr *) ehdr)->e_phnum; 185165535Sjkoshy shnum = ((Elf64_Ehdr *) ehdr)->e_shnum; 186165535Sjkoshy shoff = ((Elf64_Ehdr *) ehdr)->e_shoff; 187165535Sjkoshy strndx = ((Elf64_Ehdr *) ehdr)->e_shstrndx; 188165535Sjkoshy } 189165535Sjkoshy 190165535Sjkoshy if (shnum >= SHN_LORESERVE || 191165535Sjkoshy (shoff == 0LL && (shnum != 0 || phnum == PN_XNUM || 192165535Sjkoshy strndx == SHN_XINDEX))) { 193165535Sjkoshy LIBELF_SET_ERROR(HEADER, 0); 194165535Sjkoshy return (NULL); 195165535Sjkoshy } 196165535Sjkoshy 197165535Sjkoshy if (shnum != 0 || shoff == 0LL) { /* not using extended numbering */ 198165535Sjkoshy e->e_u.e_elf.e_nphdr = phnum; 199165535Sjkoshy e->e_u.e_elf.e_nscn = shnum; 200165535Sjkoshy e->e_u.e_elf.e_strndx = strndx; 201165535Sjkoshy } else if (_libelf_load_extended(e, ec, shoff, phnum, strndx) == 0) 202165535Sjkoshy return (NULL); 203165535Sjkoshy 204164190Sjkoshy return (ehdr); 205164190Sjkoshy} 206