/* $NetBSD: mdreloc.c,v 1.47.4.1 2023/08/04 12:55:45 martin Exp $ */ /* * Copyright (c) 2001 Wasabi Systems, Inc. * All rights reserved. * * Written by Frank van der Linden for Wasabi Systems, Inc. * * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed for the NetBSD Project by * Wasabi Systems, Inc. * 4. The name of Wasabi Systems, Inc. may not be used to endorse * or promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC * 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. */ /* * Copyright 1996 John D. Polstra. * Copyright 1996 Matt Thomas * All rights reserved. * * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by John Polstra. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 1.47.4.1 2023/08/04 12:55:45 martin Exp $"); #endif /* not lint */ #include #include #include #include #include #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); caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); static inline int _rtld_relocate_plt_object(const Obj_Entry *, const Elf_Rela *, Elf_Addr *); #define rdbg_symname(obj, rela) \ ((obj)->strtab + (obj)->symtab[ELF_R_SYM((rela)->r_info)].st_name) void _rtld_setup_pltgot(const Obj_Entry *obj) { obj->pltgot[1] = (Elf_Addr) obj; obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; } 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; } } /* * Assume only 64-bit relocations here, which should always * be true for the dynamic linker. */ 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++) { Elf64_Addr *where64; Elf32_Addr *where32; Elf64_Addr tmp64; Elf32_Addr tmp32; unsigned long symnum; where64 = (Elf64_Addr *)(obj->relocbase + rela->r_offset); where32 = (Elf32_Addr *)where64; switch (ELF_R_TYPE(rela->r_info)) { case R_TYPE(32): /* word32 S + A, truncate */ case R_TYPE(32S): /* word32 S + A, signed truncate */ case R_TYPE(GOT32): /* word32 G + A (XXX can we see these?) */ case R_TYPE(64): /* word64 S + A */ case R_TYPE(PC32): /* word32 S + A - P */ case R_TYPE(GLOB_DAT): /* word64 S */ case R_TYPE(TPOFF64): case R_TYPE(DTPMOD64): case R_TYPE(DTPOFF64): 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)) { case R_TYPE(NONE): break; case R_TYPE(32): /* word32 S + A, truncate */ case R_TYPE(32S): /* word32 S + A, signed truncate */ case R_TYPE(GOT32): /* word32 G + A (XXX can we see these?) */ tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + def->st_value + rela->r_addend); if (*where32 != tmp32) *where32 = tmp32; rdbg(("32/32S %s in %s --> %p in %s", rdbg_symname(obj, rela), obj->path, (void *)(uintptr_t)*where32, defobj->path)); break; case R_TYPE(64): /* word64 S + A */ tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value + rela->r_addend); if (*where64 != tmp64) *where64 = tmp64; rdbg(("64 %s in %s --> %p in %s", rdbg_symname(obj, rela), obj->path, (void *)*where64, defobj->path)); break; case R_TYPE(PC32): /* word32 S + A - P */ tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + def->st_value + rela->r_addend - (Elf64_Addr)where64); if (*where32 != tmp32) *where32 = tmp32; rdbg(("PC32 %s in %s --> %p in %s", rdbg_symname(obj, rela), obj->path, (void *)(unsigned long)*where32, defobj->path)); break; case R_TYPE(GLOB_DAT): /* word64 S */ tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value); if (*where64 != tmp64) *where64 = tmp64; rdbg(("64 %s in %s --> %p in %s", rdbg_symname(obj, rela), obj->path, (void *)*where64, defobj->path)); break; case R_TYPE(RELATIVE): /* word64 B + A */ tmp64 = (Elf64_Addr)(obj->relocbase + rela->r_addend); if (*where64 != tmp64) *where64 = tmp64; rdbg(("RELATIVE in %s --> %p", obj->path, (void *)*where64)); break; case R_TYPE(TPOFF64): if (!defobj->tls_static && _rtld_tls_offset_allocate(__UNCONST(defobj))) return -1; *where64 = (Elf64_Addr)(def->st_value - defobj->tlsoffset + rela->r_addend); rdbg(("TPOFF64 %s in %s --> %p", rdbg_symname(obj, rela), obj->path, (void *)*where64)); break; case R_TYPE(DTPMOD64): *where64 = (Elf64_Addr)defobj->tlsindex; rdbg(("DTPMOD64 %s in %s --> %p", rdbg_symname(obj, rela), obj->path, (void *)*where64)); break; case R_TYPE(DTPOFF64): *where64 = (Elf64_Addr)(def->st_value + rela->r_addend); rdbg(("DTPOFF64 %s in %s --> %p", rdbg_symname(obj, rela), obj->path, (void *)*where64)); break; case R_TYPE(COPY): rdbg(("COPY")); break; case R_TYPE(IRELATIVE): /* IFUNC relocations are handled in _rtld_call_ifunc */ if (obj->ifunc_remaining_nonplt == 0) { obj->ifunc_remaining_nonplt = obj->relalim - rela; } 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 *)*where64, rdbg_symname(obj, rela))); _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; for (rela = obj->pltrelalim; rela-- > obj->pltrela; ) { Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT) || ELF_R_TYPE(rela->r_info) == R_TYPE(IRELATIVE)); if (ELF_R_TYPE(rela->r_info) == R_TYPE(IRELATIVE)) obj->ifunc_remaining = obj->pltrelalim - rela; /* Just relocate the GOT slots pointing into the PLT */ *where += (Elf_Addr)obj->relocbase; rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); } return 0; } static inline int _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp) { Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); Elf_Addr new_value; const Elf_Sym *def; const Obj_Entry *defobj; unsigned long info = rela->r_info; if (ELF_R_TYPE(info) == R_TYPE(IRELATIVE)) return 0; assert(ELF_R_TYPE(info) == R_TYPE(JUMP_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; 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 + rela->r_addend); } rdbg(("bind now/fixup in %s --> old=%p new=%p", defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); if (*where != new_value) *where = new_value; if (tp) *tp = new_value - rela->r_addend; return 0; } caddr_t _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) { const Elf_Rela *rela = obj->pltrela + reloff; Elf_Addr new_value; int error; new_value = 0; /* XXX GCC4 */ _rtld_shared_enter(); error = _rtld_relocate_plt_object(obj, rela, &new_value); if (error) _rtld_die(); _rtld_shared_exit(); return (caddr_t)new_value; } int _rtld_relocate_plt_objects(const Obj_Entry *obj) { const Elf_Rela *rela; for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) return -1; return 0; }