mdreloc.c revision 1.49
1 /* $NetBSD: mdreloc.c,v 1.49 2024/08/03 21:59:59 riastradh 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 (at) 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 1.49 2024/08/03 21:59:59 riastradh 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 #define rdbg_symname(obj, rela) \ 95 ((obj)->strtab + (obj)->symtab[ELF_R_SYM((rela)->r_info)].st_name) 96 97 void 98 _rtld_setup_pltgot(const Obj_Entry *obj) 99 { 100 obj->pltgot[1] = (Elf_Addr) obj; 101 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 102 } 103 104 void 105 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 106 { 107 const Elf_Rela *rela = 0, *relalim; 108 Elf_Addr relasz = 0; 109 Elf_Addr *where; 110 111 for (; dynp->d_tag != DT_NULL; dynp++) { 112 switch (dynp->d_tag) { 113 case DT_RELA: 114 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 115 break; 116 case DT_RELASZ: 117 relasz = dynp->d_un.d_val; 118 break; 119 } 120 } 121 /* 122 * Assume only 64-bit relocations here, which should always 123 * be true for the dynamic linker. 124 */ 125 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 126 for (; rela < relalim; rela++) { 127 where = (Elf_Addr *)(relocbase + rela->r_offset); 128 *where = (Elf_Addr)(relocbase + rela->r_addend); 129 } 130 } 131 132 int 133 _rtld_relocate_nonplt_objects(Obj_Entry *obj) 134 { 135 const Elf_Rela *rela; 136 const Elf_Sym *def = NULL; 137 const Obj_Entry *defobj = NULL; 138 unsigned long last_symnum = ULONG_MAX; 139 140 for (rela = obj->rela; rela < obj->relalim; rela++) { 141 Elf64_Addr *where64; 142 Elf32_Addr *where32; 143 Elf64_Addr tmp64; 144 Elf32_Addr tmp32; 145 unsigned long symnum; 146 147 where64 = (Elf64_Addr *)(obj->relocbase + rela->r_offset); 148 where32 = (Elf32_Addr *)where64; 149 150 switch (ELF_R_TYPE(rela->r_info)) { 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 case R_TYPE(64): /* word64 S + A */ 155 case R_TYPE(PC32): /* word32 S + A - P */ 156 case R_TYPE(GLOB_DAT): /* word64 S */ 157 case R_TYPE(TPOFF64): 158 case R_TYPE(DTPMOD64): 159 case R_TYPE(DTPOFF64): 160 symnum = ELF_R_SYM(rela->r_info); 161 if (last_symnum != symnum) { 162 last_symnum = symnum; 163 def = _rtld_find_symdef(symnum, obj, &defobj, 164 false); 165 if (def == NULL) 166 return -1; 167 } 168 break; 169 default: 170 break; 171 } 172 173 switch (ELF_R_TYPE(rela->r_info)) { 174 case R_TYPE(NONE): 175 break; 176 177 case R_TYPE(32): /* word32 S + A, truncate */ 178 case R_TYPE(32S): /* word32 S + A, signed truncate */ 179 case R_TYPE(GOT32): /* word32 G + A (XXX can we see these?) */ 180 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 181 def->st_value + rela->r_addend); 182 183 if (*where32 != tmp32) 184 *where32 = tmp32; 185 rdbg(("32/32S %s in %s --> %p in %s", 186 rdbg_symname(obj, rela), 187 obj->path, (void *)(uintptr_t)*where32, 188 defobj->path)); 189 break; 190 case R_TYPE(64): /* word64 S + A */ 191 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value + 192 rela->r_addend); 193 194 if (*where64 != tmp64) 195 *where64 = tmp64; 196 rdbg(("64 %s in %s --> %p in %s", 197 rdbg_symname(obj, rela), 198 obj->path, (void *)*where64, defobj->path)); 199 break; 200 case R_TYPE(PC32): /* word32 S + A - P */ 201 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 202 def->st_value + rela->r_addend - 203 (Elf64_Addr)where64); 204 if (*where32 != tmp32) 205 *where32 = tmp32; 206 rdbg(("PC32 %s in %s --> %p in %s", 207 rdbg_symname(obj, rela), 208 obj->path, (void *)(unsigned long)*where32, 209 defobj->path)); 210 break; 211 case R_TYPE(GLOB_DAT): /* word64 S */ 212 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value); 213 214 if (*where64 != tmp64) 215 *where64 = tmp64; 216 rdbg(("64 %s in %s --> %p in %s", 217 rdbg_symname(obj, rela), 218 obj->path, (void *)*where64, defobj->path)); 219 break; 220 case R_TYPE(RELATIVE): /* word64 B + A */ 221 tmp64 = (Elf64_Addr)(obj->relocbase + rela->r_addend); 222 if (*where64 != tmp64) 223 *where64 = tmp64; 224 rdbg(("RELATIVE in %s --> %p", obj->path, 225 (void *)*where64)); 226 break; 227 228 case R_TYPE(TPOFF64): 229 if (!defobj->tls_static && 230 _rtld_tls_offset_allocate(__UNCONST(defobj))) 231 return -1; 232 233 *where64 = (Elf64_Addr)(def->st_value - 234 defobj->tlsoffset + rela->r_addend); 235 236 rdbg(("TPOFF64 %s in %s --> %p", 237 rdbg_symname(obj, rela), 238 obj->path, (void *)*where64)); 239 240 break; 241 242 case R_TYPE(DTPMOD64): 243 *where64 = (Elf64_Addr)defobj->tlsindex; 244 245 rdbg(("DTPMOD64 %s in %s --> %p", 246 rdbg_symname(obj, rela), 247 obj->path, (void *)*where64)); 248 249 break; 250 251 case R_TYPE(DTPOFF64): 252 *where64 = (Elf64_Addr)(def->st_value + rela->r_addend); 253 254 rdbg(("DTPOFF64 %s in %s --> %p", 255 rdbg_symname(obj, rela), 256 obj->path, (void *)*where64)); 257 258 break; 259 260 case R_TYPE(COPY): 261 rdbg(("COPY")); 262 break; 263 264 case R_TYPE(IRELATIVE): 265 /* IFUNC relocations are handled in _rtld_call_ifunc */ 266 if (obj->ifunc_remaining_nonplt == 0) { 267 obj->ifunc_remaining_nonplt = 268 obj->relalim - rela; 269 } 270 break; 271 272 default: 273 rdbg(("sym = %lu, type = %lu, offset = %p, " 274 "addend = %p, contents = %p, symbol = %s", 275 (u_long)ELF_R_SYM(rela->r_info), 276 (u_long)ELF_R_TYPE(rela->r_info), 277 (void *)rela->r_offset, (void *)rela->r_addend, 278 (void *)*where64, rdbg_symname(obj, rela))); 279 _rtld_error("%s: Unsupported relocation type %ld " 280 "in non-PLT relocations", 281 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 282 return -1; 283 } 284 } 285 return 0; 286 } 287 288 int 289 _rtld_relocate_plt_lazy(Obj_Entry *obj) 290 { 291 const Elf_Rela *rela; 292 293 for (rela = obj->pltrelalim; rela-- > obj->pltrela; ) { 294 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 295 296 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT) || 297 ELF_R_TYPE(rela->r_info) == R_TYPE(IRELATIVE)); 298 299 if (ELF_R_TYPE(rela->r_info) == R_TYPE(IRELATIVE)) 300 obj->ifunc_remaining = obj->pltrelalim - rela; 301 302 /* Just relocate the GOT slots pointing into the PLT */ 303 *where += (Elf_Addr)obj->relocbase; 304 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 305 } 306 307 return 0; 308 } 309 310 static inline int 311 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp) 312 { 313 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 314 Elf_Addr new_value; 315 const Elf_Sym *def; 316 const Obj_Entry *defobj; 317 unsigned long info = rela->r_info; 318 319 if (ELF_R_TYPE(info) == R_TYPE(IRELATIVE)) 320 return 0; 321 322 assert(ELF_R_TYPE(info) == R_TYPE(JUMP_SLOT)); 323 324 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 325 if (__predict_false(def == NULL)) 326 return -1; 327 if (__predict_false(def == &_rtld_sym_zero)) 328 return 0; 329 330 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 331 if (tp == NULL) 332 return 0; 333 new_value = _rtld_resolve_ifunc(defobj, def); 334 } else { 335 new_value = (Elf_Addr)(defobj->relocbase + def->st_value + 336 rela->r_addend); 337 } 338 339 rdbg(("bind now/fixup in %s --> old=%p new=%p", 340 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 341 if (*where != new_value) 342 *where = new_value; 343 344 if (tp) 345 *tp = new_value - rela->r_addend; 346 347 return 0; 348 } 349 350 caddr_t 351 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 352 { 353 const Elf_Rela *rela = obj->pltrela + reloff; 354 Elf_Addr new_value; 355 int error; 356 357 new_value = 0; /* XXX GCC4 */ 358 359 _rtld_shared_enter(); 360 error = _rtld_relocate_plt_object(obj, rela, &new_value); 361 if (error) 362 _rtld_die(); 363 _rtld_shared_exit(); 364 365 return (caddr_t)new_value; 366 } 367 368 int 369 _rtld_relocate_plt_objects(const Obj_Entry *obj) 370 { 371 const Elf_Rela *rela; 372 373 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) 374 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 375 return -1; 376 377 return 0; 378 } 379
Indexes created Thu Oct 02 01:09:59 GMT 2025