/* $NetBSD: mdreloc.c,v 1.5.2.1 2023/08/04 12:55:48 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 1.5.2.1 2023/08/04 12:55:48 martin Exp $"); #endif /* not lint */ #include #include #include #include #include #include "debug.h" #include "rtld.h" void _rtld_bind_start(void); void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); void *_rtld_bind(const Obj_Entry *, Elf_Word); void _rtld_setup_pltgot(const Obj_Entry *obj) { obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start; obj->pltgot[1] = (Elf_Addr) obj; } void _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) { const Elf_Rela *rela = NULL, *relalim; Elf_Addr relasz = 0; 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 *)((uintptr_t)rela + relasz); for (; rela < relalim; rela++) { Elf_Word r_type = ELF_R_TYPE(rela->r_info); Elf_Addr *where = (Elf_Addr *)(relocbase + rela->r_offset); switch (r_type) { case R_TYPE(RELATIVE): { Elf_Addr val = relocbase + rela->r_addend; *where = val; rdbg(("RELATIVE/L(%p) -> %p in ", where, (void *)val)); break; } case R_TYPE(NONE): break; default: abort(); } } } 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 * const where = (Elf_Addr *)(obj->relocbase + rela->r_offset); const Elf_Word r_type = ELF_R_TYPE(rela->r_info); unsigned long symnum; switch (r_type) { case R_TYPESZ(ADDR): case R_TYPESZ(TLS_DTPMOD): case R_TYPESZ(TLS_DTPREL): 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 (r_type) { case R_TYPE(NONE): break; case R_TYPE(RELATIVE): { symnum = ELF_R_SYM(rela->r_info); def = obj->symtab + symnum; Elf_Addr val = (Elf_Addr)obj->relocbase + rela->r_addend; rdbg(("RELATIVE(%p) -> %p (%s) in %s", where, (void *)val, obj->strtab + def->st_name, obj->path)); *where = val; break; } case R_TYPESZ(ADDR): { Elf_Addr val = (Elf_Addr)defobj->relocbase + rela->r_addend; *where = val; rdbg(("ADDR %s in %s --> %p in %s", obj->strtab + obj->symtab[r_symndx].st_name, obj->path, (void *)val, defobj->path)); break; } case R_TYPESZ(TLS_DTPMOD): { Elf_Addr val = (Elf_Addr)defobj->tlsindex + rela->r_addend; *where = val; rdbg(("DTPMOD %s in %s --> %p in %s", obj->strtab + obj->symtab[r_symndx].st_name, obj->path, (void *)val, defobj->path)); break; } case R_TYPESZ(TLS_DTPREL): { Elf_Addr old = *where; Elf_Addr val = old; if (!defobj->tls_static && _rtld_tls_offset_allocate(__UNCONST(defobj))) return -1; val = (Elf_Addr)def->st_value - TLS_DTV_OFFSET; *where = val; rdbg(("DTPREL %s in %s --> %p in %s", obj->strtab + obj->symtab[r_symndx].st_name, obj->path, (void *)val, 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 *)load_ptr(where, sizeof(Elf_Addr)), obj->strtab + obj->symtab[r_symndx].st_name)); _rtld_error("%s: Unsupported relocation type %ld " "in non-PLT relocations", obj->path, (u_long)r_type); return -1; } } return 0; } int _rtld_relocate_plt_lazy(Obj_Entry *obj) { /* PLT fixups were done above in the GOT relocation. */ return 0; } static int _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rel *rel, Elf_Addr *tp) { const Obj_Entry *defobj; Elf_Addr new_value; assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); const Elf_Sym *def = _rtld_find_plt_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, tp != NULL); if (__predict_false(def == NULL)) return -1; if (__predict_false(def == &_rtld_sym_zero)) return -1; if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { if (tp == NULL) return 0; new_value = _rtld_resolve_ifunc(defobj, def); } else { new_value = (Elf_Addr)(defobj->relocbase + def->st_value); } rdbg(("bind now/fixup in %s --> new=%p", defobj->strtab + def->st_name, (void *)new_value)); *(Elf_Addr *)(obj->relocbase + rel->r_offset) = new_value; if (tp) *tp = new_value; return 0; } void * _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) { const Elf_Rel *pltrel = (const Elf_Rel *)(obj->pltrel + reloff); Elf_Addr new_value; int err; _rtld_shared_enter(); err = _rtld_relocate_plt_object(obj, pltrel, &new_value); if (err) _rtld_die(); _rtld_shared_exit(); return (caddr_t)new_value; } int _rtld_relocate_plt_objects(const Obj_Entry *obj) { for (const Elf_Rel *rel = obj->pltrel; rel < obj->pltrellim; rel++) { if (_rtld_relocate_plt_object(obj, rel, NULL) < 0) return -1; } return 0; }