1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2003 Jake Burkholder. 5 * Copyright 1996-1998 John D. Polstra. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/types.h> 31 #include <machine/elf.h> 32 33 #include <err.h> 34 #include <errno.h> 35 36 #include "ef.h" 37 38 /* 39 * Apply relocations to the values we got from the file. `relbase' is the 40 * target relocation address of the section, and `dataoff' is the target 41 * relocation address of the data in `dest'. 42 */ 43 int 44 ef_reloc(struct elf_file *ef, const void *reldata, int reltype, Elf_Off relbase, 45 Elf_Off dataoff, size_t len, void *dest) 46 { 47 Elf64_Addr *where, val; 48 Elf32_Addr *where32, val32; 49 Elf_Addr addend, addr; 50 Elf_Size rtype, symidx; 51 const Elf_Rel *rel; 52 const Elf_Rela *rela; 53 54 switch (reltype) { 55 case EF_RELOC_REL: 56 rel = (const Elf_Rel *)reldata; 57 where = (Elf_Addr *)(dest + relbase + rel->r_offset - dataoff); 58 addend = 0; 59 rtype = ELF_R_TYPE(rel->r_info); 60 symidx = ELF_R_SYM(rel->r_info); 61 break; 62 case EF_RELOC_RELA: 63 rela = (const Elf_Rela *)reldata; 64 where = (Elf_Addr *)(dest + relbase + rela->r_offset - dataoff); 65 addend = rela->r_addend; 66 rtype = ELF_R_TYPE(rela->r_info); 67 symidx = ELF_R_SYM(rela->r_info); 68 break; 69 default: 70 return (EINVAL); 71 } 72 73 if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len) 74 return (0); 75 76 if (reltype == EF_RELOC_REL) { 77 /* Addend is 32 bit on 32 bit relocs */ 78 switch (rtype) { 79 case R_X86_64_PC32: 80 case R_X86_64_32S: 81 addend = *(Elf32_Addr *)where; 82 break; 83 default: 84 addend = *where; 85 break; 86 } 87 } 88 89 switch (rtype) { 90 case R_X86_64_NONE: /* none */ 91 break; 92 case R_X86_64_64: /* S + A */ 93 addr = EF_SYMADDR(ef, symidx); 94 val = addr + addend; 95 *where = val; 96 break; 97 case R_X86_64_32S: /* S + A sign extend */ 98 addr = EF_SYMADDR(ef, symidx); 99 val32 = (Elf32_Addr)(addr + addend); 100 where32 = (Elf32_Addr *)where; 101 *where32 = val32; 102 break; 103 case R_X86_64_GLOB_DAT: /* S */ 104 addr = EF_SYMADDR(ef, symidx); 105 *where = addr; 106 break; 107 case R_X86_64_RELATIVE: /* B + A */ 108 addr = (Elf_Addr)addend + relbase; 109 val = addr; 110 *where = val; 111 break; 112 default: 113 warnx("unhandled relocation type %d", (int)rtype); 114 } 115 return (0); 116 } 117