libexec/ld.elf_so/arch/x86_64/mdreloc.c

   1 /*      $NetBSD: mdreloc.c,v 1.38 2010/08/06 16:33:19 joerg Exp $       */
   2
   3 /*
   4  * Copyright (c) 2001 Wasabi Systems, Inc.
   5  * All rights reserved.
   6  *
   7  * Written by Frank van der Linden for Wasabi Systems, Inc.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed for the NetBSD Project by
  20  *      Wasabi Systems, Inc.
  21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
  22  *    or promote products derived from this software without specific prior
  23  *    written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
  29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  35  * POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 /*
  39  * Copyright 1996 John D. Polstra.
  40  * Copyright 1996 Matt Thomas <matt@3am-software.com>
  41  * All rights reserved.
  42  *
  43  * Redistribution and use in source and binary forms, with or without
  44  * modification, are permitted provided that the following conditions
  45  * are met:
  46  * 1. Redistributions of source code must retain the above copyright
  47  *    notice, this list of conditions and the following disclaimer.
  48  * 2. Redistributions in binary form must reproduce the above copyright
  49  *    notice, this list of conditions and the following disclaimer in the
  50  *    documentation and/or other materials provided with the distribution.
  51  * 3. All advertising materials mentioning features or use of this software
  52  *    must display the following acknowledgement:
  53  *      This product includes software developed by John Polstra.
  54  * 4. The name of the author may not be used to endorse or promote products
  55  *    derived from this software without specific prior written permission.
  56  *
  57  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  58  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  59  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  60  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  61  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  62  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  63  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  64  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  65  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  66  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  67  */
  68
  69 #include <sys/cdefs.h>
  70 #ifndef lint
  71 __RCSID("$NetBSD: mdreloc.c,v 1.38 2010/08/06 16:33:19 joerg Exp $");
  72 #endif /* not lint */
  73
  74 #include <sys/types.h>
  75 #include <sys/mman.h>
  76 #include <errno.h>
  77 #include <fcntl.h>
  78 #include <stdarg.h>
  79 #include <stdio.h>
  80 #include <stdlib.h>
  81 #include <string.h>
  82 #include <unistd.h>
  83 #include <elf.h>
  84
  85 #include "debug.h"
  86 #include "rtld.h"
  87
  88 void _rtld_bind_start(void);
  89 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
  90 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
  91 static inline int _rtld_relocate_plt_object(const Obj_Entry *,
  92     const Elf_Rela *, Elf_Addr *);
  93
  94 void
  95 _rtld_setup_pltgot(const Obj_Entry *obj)
  96 {
  97         obj->pltgot[1] = (Elf_Addr) obj;
  98         obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
  99 }
 100
 101 void
 102 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
 103 {
 104         const Elf_Rela *rela = 0, *relalim;
 105         Elf_Addr relasz = 0;
 106         Elf_Addr *where;
 107
 108         for (; dynp->d_tag != DT_NULL; dynp++) {
 109                 switch (dynp->d_tag) {
 110                 case DT_RELA:
 111                         rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr);
 112                         break;
 113                 case DT_RELASZ:
 114                         relasz = dynp->d_un.d_val;
 115                         break;
 116                 }
 117         }
 118         /*
 119          * Assume only 64-bit relocations here, which should always
 120          * be true for the dynamic linker.
 121          */
 122         relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz);
 123         for (; rela < relalim; rela++) {
 124                 where = (Elf_Addr *)(relocbase + rela->r_offset);
 125                 *where = (Elf_Addr)(relocbase + rela->r_addend);
 126         }
 127 }
 128
 129 int
 130 _rtld_relocate_nonplt_objects(Obj_Entry *obj)
 131 {
 132         const Elf_Rela *rela;
 133         const Elf_Sym *def = NULL;
 134         const Obj_Entry *defobj =NULL;
 135
 136         for (rela = obj->rela; rela < obj->relalim; rela++) {
 137                 Elf64_Addr *where64;
 138                 Elf32_Addr *where32;
 139                 Elf64_Addr tmp64;
 140                 Elf32_Addr tmp32;
 141                 unsigned long    symnum;
 142
 143                 where64 = (Elf64_Addr *)(obj->relocbase + rela->r_offset);
 144                 where32 = (Elf32_Addr *)where64;
 145                 symnum = ELF_R_SYM(rela->r_info);
 146
 147                 switch (ELF_R_TYPE(rela->r_info)) {
 148                 case R_TYPE(NONE):
 149                         break;
 150
 151                 case R_TYPE(32):        /* word32 S + A, truncate */
 152                 case R_TYPE(32S):       /* word32 S + A, signed truncate */
 153                 case R_TYPE(GOT32):     /* word32 G + A (XXX can we see these?) */
 154                         def = _rtld_find_symdef(symnum, obj, &defobj, false);
 155                         if (def == NULL)
 156                                 return -1;
 157                         tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase +
 158                             def->st_value + rela->r_addend);
 159
 160                         if (*where32 != tmp32)
 161                                 *where32 = tmp32;
 162                         rdbg(("32/32S %s in %s --> %p in %s",
 163                             obj->strtab + obj->symtab[symnum].st_name,
 164                             obj->path, (void *)(unsigned long)*where32,
 165                             defobj->path));
 166                         break;
 167                 case R_TYPE(64):        /* word64 S + A */
 168                         def = _rtld_find_symdef(symnum, obj, &defobj, false);
 169                         if (def == NULL)
 170                                 return -1;
 171                         tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value +
 172                             rela->r_addend);
 173
 174                         if (*where64 != tmp64)
 175                                 *where64 = tmp64;
 176                         rdbg(("64 %s in %s --> %p in %s",
 177                             obj->strtab + obj->symtab[symnum].st_name,
 178                             obj->path, (void *)*where64, defobj->path));
 179                         break;
 180                 case R_TYPE(PC32):      /* word32 S + A - P */
 181                         def = _rtld_find_symdef(symnum, obj, &defobj, false);
 182                         if (def == NULL)
 183                                 return -1;
 184                         tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase +
 185                             def->st_value + rela->r_addend -
 186                             (Elf64_Addr)where64);
 187                         if (*where32 != tmp32)
 188                                 *where32 = tmp32;
 189                         rdbg(("PC32 %s in %s --> %p in %s",
 190                             obj->strtab + obj->symtab[symnum].st_name,
 191                             obj->path, (void *)(unsigned long)*where32,
 192                             defobj->path));
 193                         break;
 194                 case R_TYPE(GLOB_DAT):  /* word64 S */
 195                         def = _rtld_find_symdef(symnum, obj, &defobj, false);
 196                         if (def == NULL)
 197                                 return -1;
 198                         tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value);
 199
 200                         if (*where64 != tmp64)
 201                                 *where64 = tmp64;
 202                         rdbg(("64 %s in %s --> %p in %s",
 203                             obj->strtab + obj->symtab[symnum].st_name,
 204                             obj->path, (void *)*where64, defobj->path));
 205                         break;
 206                 case R_TYPE(RELATIVE):  /* word64 B + A */
 207                         tmp64 = (Elf64_Addr)(obj->relocbase + rela->r_addend);
 208                         if (*where64 != tmp64)
 209                                 *where64 = tmp64;
 210                         rdbg(("RELATIVE in %s --> %p", obj->path,
 211                             (void *)*where64));
 212                         break;
 213
 214                 case R_TYPE(COPY):
 215                         rdbg(("COPY"));
 216                         break;
 217
 218                 default:
 219                         rdbg(("sym = %lu, type = %lu, offset = %p, "
 220                             "addend = %p, contents = %p, symbol = %s",
 221                             symnum, (u_long)ELF_R_TYPE(rela->r_info),
 222                             (void *)rela->r_offset, (void *)rela->r_addend,
 223                             (void *)*where64,
 224                             obj->strtab + obj->symtab[symnum].st_name));
 225                         _rtld_error("%s: Unsupported relocation type %ld "
 226                             "in non-PLT relocations",
 227                             obj->path, (u_long) ELF_R_TYPE(rela->r_info));
 228                         return -1;
 229                 }
 230         }
 231         return 0;
 232 }
 233
 234 int
 235 _rtld_relocate_plt_lazy(const Obj_Entry *obj)
 236 {
 237         const Elf_Rela *rela;
 238
 239         if (!obj->relocbase)
 240                 return 0;
 241
 242         for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) {
 243                 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
 244
 245                 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT));
 246
 247                 /* Just relocate the GOT slots pointing into the PLT */
 248                 *where += (Elf_Addr)obj->relocbase;
 249                 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where));
 250         }
 251
 252         return 0;
 253 }
 254
 255 static inline int
 256 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp)
 257 {
 258         Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
 259         Elf_Addr new_value;
 260         const Elf_Sym  *def;
 261         const Obj_Entry *defobj;
 262         unsigned long info = rela->r_info;
 263
 264         assert(ELF_R_TYPE(info) == R_TYPE(JUMP_SLOT));
 265
 266         def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL);
 267         if (__predict_false(def == NULL))
 268                 return -1;
 269         if (__predict_false(def == &_rtld_sym_zero))
 270                 return 0;
 271
 272         new_value = (Elf_Addr)(defobj->relocbase + def->st_value +
 273             rela->r_addend);
 274         rdbg(("bind now/fixup in %s --> old=%p new=%p",
 275             defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
 276         if (*where != new_value)
 277                 *where = new_value;
 278
 279         if (tp)
 280                 *tp = new_value - rela->r_addend;
 281
 282         return 0;
 283 }
 284
 285 caddr_t
 286 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff)
 287 {
 288         const Elf_Rela *rela = obj->pltrela + reloff;
 289         Elf_Addr new_value;
 290         int error;
 291
 292         new_value = 0; /* XXX GCC4 */
 293
 294         error = _rtld_relocate_plt_object(obj, rela, &new_value);
 295         if (error)
 296                 _rtld_die();
 297
 298         return (caddr_t)new_value;
 299 }
 300
 301 int
 302 _rtld_relocate_plt_objects(const Obj_Entry *obj)
 303 {
 304         const Elf_Rela *rela;
 305
 306         for (rela = obj->pltrela; rela < obj->pltrelalim; rela++)
 307                 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0)
 308                         return -1;
 309
 310         return 0;
 311 }