1/* $OpenBSD: boot_md.c,v 1.6 2022/01/31 05:43:22 guenther Exp $ */ 2 3/* 4 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 */ 28 29/* 30 * IMPORTANT: any functions below are NOT protected by SSP. Please 31 * do not add anything except what is required to reach GOT with 32 * an adjustment. 33 */ 34 35#define _DYN_LOADER 36 37#include <sys/exec_elf.h> 38 39#include "util.h" 40#include "archdep.h" /* for RELOC_TAG */ 41 42#include "../../lib/csu/os-note-elf.h" 43 44typedef Elf_RelA RELOC_TYPE; 45 46/* 47 * Local decls. 48 */ 49void _dl_boot_bind(const long, long *, Elf_Dyn *) __boot; 50 51void 52_dl_boot_bind(const long sp, long *dl_data, Elf_Dyn *dynp) 53{ 54 AuxInfo *auxstack; 55 long *stack; 56 int n, argc; 57 char **argv, **envp; 58 long loff; 59 const RELOC_TYPE *rend; 60 const RELOC_TYPE *dt_reloc; /* DT_RELA */ 61 Elf_Addr dt_relocsz; /* DT_RELASZ */ 62 Elf_Addr dt_pltgot; 63 Elf_Addr dt_pltrelsz; 64 const Elf_Sym *dt_symtab; 65 const RELOC_TYPE *dt_jmprel; 66 67 /* 68 * Scan argument and environment vectors. Find dynamic 69 * data vector put after them. 70 */ 71 stack = (long *)sp; 72 argc = *stack++; 73 argv = (char **)stack; 74 envp = &argv[argc + 1]; 75 stack = (long *)envp; 76 while (*stack++ != 0L) 77 ; 78 79 /* 80 * Zero out dl_data. 81 */ 82 for (n = 0; n <= AUX_entry; n++) 83 dl_data[n] = 0; 84 85 /* 86 * Dig out auxiliary data set up by exec call. Move all known 87 * tags to an indexed local table for easy access. 88 */ 89 for (auxstack = (AuxInfo *)stack; auxstack->au_id != AUX_null; 90 auxstack++) { 91 if (auxstack->au_id > AUX_entry) 92 continue; 93 dl_data[auxstack->au_id] = auxstack->au_v; 94 } 95 loff = dl_data[AUX_base]; /* XXX assumes ld.so is linked at 0x0 */ 96 97 /* 98 * Scan the DYNAMIC section for the loader for the two items we need 99 */ 100 dt_pltrelsz = dt_relocsz = dt_pltgot = 0; 101 dt_jmprel = dt_reloc = NULL; 102 dt_symtab = NULL; 103 while (dynp->d_tag != DT_NULL) { 104 /* first the tags that are pointers to be relocated */ 105 if (dynp->d_tag == DT_PLTGOT) 106 dt_pltgot = dynp->d_un.d_ptr + loff; 107 else if (dynp->d_tag == DT_SYMTAB) 108 dt_symtab = (void *)(dynp->d_un.d_ptr + loff); 109 else if (dynp->d_tag == RELOC_TAG) /* DT_{RELA,REL} */ 110 dt_reloc = (void *)(dynp->d_un.d_ptr + loff); 111 else if (dynp->d_tag == DT_JMPREL) 112 dt_jmprel = (void *)(dynp->d_un.d_ptr + loff); 113 114 /* Now for the tags that are just sizes or counts */ 115 else if (dynp->d_tag == DT_PLTRELSZ) 116 dt_pltrelsz = dynp->d_un.d_val; 117 else if (dynp->d_tag == RELOC_TAG+1) /* DT_{RELA,REL}SZ */ 118 dt_relocsz = dynp->d_un.d_val; 119 dynp++; 120 } 121 122 rend = (RELOC_TYPE *)((char *)dt_jmprel + dt_pltrelsz); 123 for (; dt_jmprel < rend; dt_jmprel++) { 124 Elf_Addr *ra; 125 const Elf_Sym *sp; 126 127 sp = dt_symtab + ELF_R_SYM(dt_jmprel->r_info); 128 ra = (Elf_Addr *)(dt_jmprel->r_offset + loff); 129 ra[0] = loff + sp->st_value + dt_jmprel->r_addend; 130 ra[1] = dt_pltgot; 131 } 132 133 rend = (RELOC_TYPE *)((char *)dt_reloc + dt_relocsz); 134 for (; dt_reloc < rend; dt_reloc++) { 135 Elf_Addr *ra; 136 const Elf_Sym *sp; 137 138 sp = dt_symtab + ELF_R_SYM(dt_reloc->r_info); 139 ra = (Elf_Addr *)(dt_reloc->r_offset + loff); 140 *ra = loff + sp->st_value + dt_reloc->r_addend; 141 } 142} 143