/* $NetBSD: mdreloc.c,v 1.3.14.1 2023/08/01 16:35:00 martin Exp $ */ /*- * Copyright (c) 2014 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Matt Thomas of 3am Software Foundry. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include #ifndef lint __RCSID("$NetBSD: mdreloc.c,v 1.3.14.1 2023/08/01 16:35:00 martin Exp $"); #endif /* not lint */ #include #include #include #include #include #include #include "debug.h" #include "rtld.h" void _rtld_bind_start(void); Elf_Addr _rtld_bind(const Obj_Entry *, Elf_Word); void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); static int _rtld_relocate_plt_object(const Obj_Entry *, const Elf_Rela *, int, Elf_Addr *); /* * The OR1k PLT format is simple. */ void _rtld_setup_pltgot(const Obj_Entry *obj) { obj->pltgot[1] = (Elf_Addr) obj; obj->pltgot[2] = (Elf_Addr) _rtld_bind_start; dbg(("obj %s plt pltgot=%p start=%p obj=%p", obj->path, obj->pltgot, (void *) obj->pltgot[1], (void *) obj->pltgot[2])); } void _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) { const Elf_Rela *rela = 0, *relalim; Elf_Addr relasz = 0; Elf_Addr *where; for (; dynp->d_tag != DT_NULL; dynp++) { switch (dynp->d_tag) { case DT_RELA: rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); break; case DT_RELASZ: relasz = dynp->d_un.d_val; break; } } relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); for (; rela < relalim; rela++) { where = (Elf_Addr *)(relocbase + rela->r_offset); *where = (Elf_Addr)(relocbase + rela->r_addend); } } int _rtld_relocate_nonplt_objects(Obj_Entry *obj) { const Elf_Rela *rela; const Elf_Sym *def = NULL; const Obj_Entry *defobj = NULL; unsigned long last_symnum = ULONG_MAX; for (rela = obj->rela; rela < obj->relalim; rela++) { Elf_Addr *where; Elf_Addr tmp; unsigned long symnum; where = (Elf_Addr *)(obj->relocbase + rela->r_offset); switch (ELF_R_TYPE(rela->r_info)) { case R_TYPE(32): /*
S + A */ case R_TYPE(GLOB_DAT): /*
S + A */ case R_TYPE(TLS_DTPMOD): case R_TYPE(TLS_DTPOFF): case R_TYPE(TLS_TPOFF): symnum = ELF_R_SYM(rela->r_info); if (last_symnum != symnum) { last_symnum = symnum; def = _rtld_find_symdef(symnum, obj, &defobj, false); if (def == NULL) return -1; } break; default: break; } switch (ELF_R_TYPE(rela->r_info)) { #if 1 /* XXX Should not be necessary. */ case R_TYPE(JMP_SLOT): #endif case R_TYPE(NONE): break; case R_TYPE(32): /*
S + A */ case R_TYPE(GLOB_DAT): /*
S + A */ tmp = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend); if (*where != tmp) *where = tmp; rdbg(("32/GLOB_DAT %s in %s --> %p in %s", obj->strtab + obj->symtab[symnum].st_name, obj->path, (void *)*where, defobj->path)); break; case R_TYPE(RELATIVE): /*
B + A */ *where = (Elf_Addr)(obj->relocbase + rela->r_addend); rdbg(("RELATIVE in %s --> %p", obj->path, (void *)*where)); break; case R_TYPE(COPY): /* * These are deferred until all other relocations have * been done. All we do here is make sure that the * COPY relocation is not in a shared library. They * are allowed only in executable files. */ if (obj->isdynamic) { _rtld_error( "%s: Unexpected R_COPY relocation in shared library", obj->path); return -1; } rdbg(("COPY (avoid in main)")); break; case R_TYPE(TLS_DTPMOD): *where = (Elf_Addr)defobj->tlsindex; rdbg(("DTPMOD32 %s in %s --> %p in %s", obj->strtab + obj->symtab[symnum].st_name, obj->path, (void *)*where, defobj->path)); break; case R_TYPE(TLS_DTPOFF): *where = (Elf_Addr)(def->st_value + rela->r_addend - TLS_DTV_OFFSET); rdbg(("DTPOFF %s in %s --> %p in %s", obj->strtab + obj->symtab[symnum].st_name, obj->path, (void *)*where, defobj->path)); break; case R_TYPE(TLS_TPOFF): if (!defobj->tls_static && _rtld_tls_offset_allocate(__UNCONST(defobj))) return -1; *where = (Elf_Addr)(def->st_value + rela->r_addend + defobj->tlsoffset - TLS_TP_OFFSET); rdbg(("TPREL %s in %s --> %p in %s", obj->strtab + obj->symtab[symnum].st_name, obj->path, (void *)*where, defobj->path)); break; default: rdbg(("sym = %lu, type = %lu, offset = %p, " "addend = %p, contents = %p, symbol = %s", (u_long)ELF_R_SYM(rela->r_info), (u_long)ELF_R_TYPE(rela->r_info), (void *)rela->r_offset, (void *)rela->r_addend, (void *)*where, obj->strtab + obj->symtab[symnum].st_name)); _rtld_error("%s: Unsupported relocation type %ld " "in non-PLT relocations", obj->path, (u_long) ELF_R_TYPE(rela->r_info)); return -1; } } return 0; } int _rtld_relocate_plt_lazy(Obj_Entry *obj) { const Elf_Rela *rela; int reloff; for (rela = obj->pltrela, reloff = 0; rela < obj->pltrelalim; rela++, reloff++) { Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); /* * For now, simply treat then as relative. */ *where += (Elf_Addr)obj->relocbase; } return 0; } static int _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, int reloff, Elf_Addr *tp) { Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); Elf_Addr value; const Elf_Sym *def; const Obj_Entry *defobj; unsigned long info = rela->r_info; assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); if (__predict_false(def == NULL)) return -1; if (__predict_false(def == &_rtld_sym_zero)) return 0; value = (Elf_Addr)(defobj->relocbase + def->st_value); rdbg(("bind now/fixup in %s --> new=%p", defobj->strtab + def->st_name, (void *)value)); /* * Simply replace the entry in GOT with the * address of the routine. */ assert(where >= (Elf_Word *)obj->pltgot); assert(where < (Elf_Word *)obj->pltgot + (obj->pltrelalim - obj->pltrela)); *where = value; if (tp) *tp = value; return 0; } Elf_Addr _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) { const Elf_Rela *rela = obj->pltrela + reloff; Elf_Addr new_value; int err; new_value = 0; /* XXX gcc */ _rtld_shared_enter(); err = _rtld_relocate_plt_object(obj, rela, reloff, &new_value); if (err) _rtld_die(); _rtld_shared_exit(); return new_value; } int _rtld_relocate_plt_objects(const Obj_Entry *obj) { const Elf_Rela *rela; int reloff; for (rela = obj->pltrela, reloff = 0; rela < obj->pltrelalim; rela++, reloff++) { if (_rtld_relocate_plt_object(obj, rela, reloff, NULL) < 0) return -1; } return 0; }