1 /*- 2 * Copyright (c) 2015-2017 Ruslan Bukin <br@bsdpad.com> 3 * All rights reserved. 4 * 5 * This software was developed by SRI International and the University of 6 * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237 7 * ("CTSRD"), as part of the DARPA CRASH research programme. 8 * 9 * This software was developed by the University of Cambridge Computer 10 * Laboratory as part of the CTSRD Project, with support from the UK Higher 11 * Education Innovation Fund (HEIF). 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/types.h> 36 37 #include <stdlib.h> 38 39 #include "debug.h" 40 #include "rtld.h" 41 #include "rtld_printf.h" 42 43 /* 44 * It is possible for the compiler to emit relocations for unaligned data. 45 * We handle this situation with these inlines. 46 */ 47 #define RELOC_ALIGNED_P(x) \ 48 (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0) 49 50 uint64_t 51 set_gp(Obj_Entry *obj) 52 { 53 uint64_t old; 54 SymLook req; 55 uint64_t gp; 56 int res; 57 58 __asm __volatile("mv %0, gp" : "=r"(old)); 59 60 symlook_init(&req, "__global_pointer$"); 61 req.ventry = NULL; 62 req.flags = SYMLOOK_EARLY; 63 res = symlook_obj(&req, obj); 64 65 if (res == 0) { 66 gp = req.sym_out->st_value; 67 __asm __volatile("mv gp, %0" :: "r"(gp)); 68 } 69 70 return (old); 71 } 72 73 void 74 init_pltgot(Obj_Entry *obj) 75 { 76 77 if (obj->pltgot != NULL) { 78 obj->pltgot[0] = (Elf_Addr)&_rtld_bind_start; 79 obj->pltgot[1] = (Elf_Addr)obj; 80 } 81 } 82 83 int 84 do_copy_relocations(Obj_Entry *dstobj) 85 { 86 const Obj_Entry *srcobj, *defobj; 87 const Elf_Rela *relalim; 88 const Elf_Rela *rela; 89 const Elf_Sym *srcsym; 90 const Elf_Sym *dstsym; 91 const void *srcaddr; 92 const char *name; 93 void *dstaddr; 94 SymLook req; 95 size_t size; 96 int res; 97 98 /* 99 * COPY relocs are invalid outside of the main program 100 */ 101 assert(dstobj->mainprog); 102 103 relalim = (const Elf_Rela *)((const char *)dstobj->rela + 104 dstobj->relasize); 105 for (rela = dstobj->rela; rela < relalim; rela++) { 106 if (ELF_R_TYPE(rela->r_info) != R_RISCV_COPY) 107 continue; 108 109 dstaddr = (void *)(dstobj->relocbase + rela->r_offset); 110 dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info); 111 name = dstobj->strtab + dstsym->st_name; 112 size = dstsym->st_size; 113 114 symlook_init(&req, name); 115 req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info)); 116 req.flags = SYMLOOK_EARLY; 117 118 for (srcobj = globallist_next(dstobj); srcobj != NULL; 119 srcobj = globallist_next(srcobj)) { 120 res = symlook_obj(&req, srcobj); 121 if (res == 0) { 122 srcsym = req.sym_out; 123 defobj = req.defobj_out; 124 break; 125 } 126 } 127 if (srcobj == NULL) { 128 _rtld_error( 129 "Undefined symbol \"%s\" referenced from COPY relocation in %s", 130 name, dstobj->path); 131 return (-1); 132 } 133 134 srcaddr = (const void *)(defobj->relocbase + srcsym->st_value); 135 memcpy(dstaddr, srcaddr, size); 136 } 137 138 return (0); 139 } 140 141 /* 142 * Process the PLT relocations. 143 */ 144 int 145 reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused) 146 { 147 const Elf_Rela *relalim; 148 const Elf_Rela *rela; 149 150 relalim = (const Elf_Rela *)((const char *)obj->pltrela + 151 obj->pltrelasize); 152 for (rela = obj->pltrela; rela < relalim; rela++) { 153 Elf_Addr *where; 154 155 assert(ELF_R_TYPE(rela->r_info) == R_RISCV_JUMP_SLOT); 156 157 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 158 *where += (Elf_Addr)obj->relocbase; 159 } 160 161 return (0); 162 } 163 164 /* 165 * LD_BIND_NOW was set - force relocation for all jump slots 166 */ 167 int 168 reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate) 169 { 170 const Obj_Entry *defobj; 171 const Elf_Rela *relalim; 172 const Elf_Rela *rela; 173 const Elf_Sym *def; 174 175 relalim = (const Elf_Rela *)((const char *)obj->pltrela + 176 obj->pltrelasize); 177 for (rela = obj->pltrela; rela < relalim; rela++) { 178 Elf_Addr *where; 179 180 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 181 switch(ELF_R_TYPE(rela->r_info)) { 182 case R_RISCV_JUMP_SLOT: 183 def = find_symdef(ELF_R_SYM(rela->r_info), obj, 184 &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate); 185 if (def == NULL) { 186 dbg("reloc_jmpslots: sym not found"); 187 return (-1); 188 } 189 190 *where = (Elf_Addr)(defobj->relocbase + def->st_value); 191 break; 192 default: 193 _rtld_error("Unknown relocation type %x in jmpslot", 194 (unsigned int)ELF_R_TYPE(rela->r_info)); 195 return (-1); 196 } 197 } 198 199 return (0); 200 } 201 202 int 203 reloc_iresolve(Obj_Entry *obj __unused, 204 struct Struct_RtldLockState *lockstate __unused) 205 { 206 207 /* XXX not implemented */ 208 return (0); 209 } 210 211 int 212 reloc_iresolve_nonplt(Obj_Entry *obj __unused, 213 struct Struct_RtldLockState *lockstate __unused) 214 { 215 216 /* XXX not implemented */ 217 return (0); 218 } 219 220 int 221 reloc_gnu_ifunc(Obj_Entry *obj __unused, int flags __unused, 222 struct Struct_RtldLockState *lockstate __unused) 223 { 224 225 /* XXX not implemented */ 226 return (0); 227 } 228 229 Elf_Addr 230 reloc_jmpslot(Elf_Addr *where, Elf_Addr target, 231 const Obj_Entry *defobj __unused, const Obj_Entry *obj __unused, 232 const Elf_Rel *rel) 233 { 234 235 assert(ELF_R_TYPE(rel->r_info) == R_RISCV_JUMP_SLOT); 236 237 if (*where != target && !ld_bind_not) 238 *where = target; 239 return (target); 240 } 241 242 /* 243 * Process non-PLT relocations 244 */ 245 int 246 reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags, 247 RtldLockState *lockstate) 248 { 249 const Obj_Entry *defobj; 250 const Elf_Rela *relalim; 251 const Elf_Rela *rela; 252 const Elf_Sym *def; 253 SymCache *cache; 254 Elf_Addr *where; 255 unsigned long symnum; 256 257 if ((flags & SYMLOOK_IFUNC) != 0) 258 /* XXX not implemented */ 259 return (0); 260 261 /* 262 * The dynamic loader may be called from a thread, we have 263 * limited amounts of stack available so we cannot use alloca(). 264 */ 265 if (obj == obj_rtld) 266 cache = NULL; 267 else 268 cache = calloc(obj->dynsymcount, sizeof(SymCache)); 269 /* No need to check for NULL here */ 270 271 relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize); 272 for (rela = obj->rela; rela < relalim; rela++) { 273 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 274 symnum = ELF_R_SYM(rela->r_info); 275 276 switch (ELF_R_TYPE(rela->r_info)) { 277 case R_RISCV_JUMP_SLOT: 278 /* This will be handled by the plt/jmpslot routines */ 279 break; 280 case R_RISCV_NONE: 281 break; 282 case R_RISCV_64: 283 def = find_symdef(symnum, obj, &defobj, flags, cache, 284 lockstate); 285 if (def == NULL) 286 return (-1); 287 288 *where = (Elf_Addr)(defobj->relocbase + def->st_value + 289 rela->r_addend); 290 break; 291 case R_RISCV_TLS_DTPMOD64: 292 def = find_symdef(symnum, obj, &defobj, flags, cache, 293 lockstate); 294 if (def == NULL) 295 return -1; 296 297 *where += (Elf_Addr)defobj->tlsindex; 298 break; 299 case R_RISCV_COPY: 300 /* 301 * These are deferred until all other relocations have 302 * been done. All we do here is make sure that the 303 * COPY relocation is not in a shared library. They 304 * are allowed only in executable files. 305 */ 306 if (!obj->mainprog) { 307 _rtld_error("%s: Unexpected R_RISCV_COPY " 308 "relocation in shared library", obj->path); 309 return (-1); 310 } 311 break; 312 case R_RISCV_TLS_DTPREL64: 313 def = find_symdef(symnum, obj, &defobj, flags, cache, 314 lockstate); 315 if (def == NULL) 316 return (-1); 317 /* 318 * We lazily allocate offsets for static TLS as we 319 * see the first relocation that references the 320 * TLS block. This allows us to support (small 321 * amounts of) static TLS in dynamically loaded 322 * modules. If we run out of space, we generate an 323 * error. 324 */ 325 if (!defobj->tls_static) { 326 if (!allocate_tls_offset( 327 __DECONST(Obj_Entry *, defobj))) { 328 _rtld_error( 329 "%s: No space available for static " 330 "Thread Local Storage", obj->path); 331 return (-1); 332 } 333 } 334 335 *where += (Elf_Addr)(def->st_value + rela->r_addend 336 - TLS_DTV_OFFSET); 337 break; 338 case R_RISCV_TLS_TPREL64: 339 def = find_symdef(symnum, obj, &defobj, flags, cache, 340 lockstate); 341 if (def == NULL) 342 return (-1); 343 344 /* 345 * We lazily allocate offsets for static TLS as we 346 * see the first relocation that references the 347 * TLS block. This allows us to support (small 348 * amounts of) static TLS in dynamically loaded 349 * modules. If we run out of space, we generate an 350 * error. 351 */ 352 if (!defobj->tls_static) { 353 if (!allocate_tls_offset( 354 __DECONST(Obj_Entry *, defobj))) { 355 _rtld_error( 356 "%s: No space available for static " 357 "Thread Local Storage", obj->path); 358 return (-1); 359 } 360 } 361 362 *where = (def->st_value + rela->r_addend + 363 defobj->tlsoffset - TLS_TP_OFFSET - TLS_TCB_SIZE); 364 break; 365 case R_RISCV_RELATIVE: 366 *where = (Elf_Addr)(obj->relocbase + rela->r_addend); 367 break; 368 default: 369 rtld_printf("%s: Unhandled relocation %lu\n", 370 obj->path, ELF_R_TYPE(rela->r_info)); 371 return (-1); 372 } 373 } 374 375 return (0); 376 } 377 378 void 379 ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused) 380 { 381 382 } 383 384 void 385 allocate_initial_tls(Obj_Entry *objs) 386 { 387 388 /* 389 * Fix the size of the static TLS block by using the maximum 390 * offset allocated so far and adding a bit for dynamic modules to 391 * use. 392 */ 393 tls_static_space = tls_last_offset + tls_last_size + 394 ld_static_tls_extra; 395 396 _tcb_set(allocate_tls(objs, NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN)); 397 } 398 399 void * 400 __tls_get_addr(tls_index* ti) 401 { 402 uintptr_t **dtvp; 403 void *p; 404 405 dtvp = &_tcb_get()->tcb_dtv; 406 p = tls_get_addr_common(dtvp, ti->ti_module, ti->ti_offset); 407 408 return ((char*)p + TLS_DTV_OFFSET); 409 } 410