diff --git a/libexec/rtld-elf/aarch64/reloc.c b/libexec/rtld-elf/aarch64/reloc.c index 78e2e2b1aaae..5dfe19e3d4f4 100644 --- a/libexec/rtld-elf/aarch64/reloc.c +++ b/libexec/rtld-elf/aarch64/reloc.c @@ -1,628 +1,637 @@ /*- * Copyright (c) 2014-2015 The FreeBSD Foundation * All rights reserved. * * Portions of this software were developed by Andrew Turner * under sponsorship from the FreeBSD Foundation. * * 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 AUTHOR 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 AUTHOR 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 #include #include #include "debug.h" #include "rtld.h" #include "rtld_printf.h" /* * It is possible for the compiler to emit relocations for unaligned data. * We handle this situation with these inlines. */ #define RELOC_ALIGNED_P(x) \ (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0) /* * This is not the correct prototype, but we only need it for * a function pointer to a simple asm function. */ void *_rtld_tlsdesc_static(void *); void *_rtld_tlsdesc_undef(void *); void *_rtld_tlsdesc_dynamic(void *); void _exit(int); bool arch_digest_dynamic(struct Struct_Obj_Entry *obj, const Elf_Dyn *dynp) { if (dynp->d_tag == DT_AARCH64_VARIANT_PCS) { obj->variant_pcs = true; return (true); } return (false); } bool arch_digest_note(struct Struct_Obj_Entry *obj __unused, const Elf_Note *note) { const char *note_name; const uint32_t *note_data; note_name = (const char *)(note + 1); /* Only handle GNU notes */ if (note->n_namesz != sizeof(ELF_NOTE_GNU) || strncmp(note_name, ELF_NOTE_GNU, sizeof(ELF_NOTE_GNU)) != 0) return (false); /* Only handle GNU property notes */ if (note->n_type != NT_GNU_PROPERTY_TYPE_0) return (false); /* * note_data[0] - Type * note_data[1] - Length * note_data[2] - Data * note_data[3] - Padding? */ note_data = (const uint32_t *)(note_name + note->n_namesz); /* Only handle AArch64 feature notes */ if (note_data[0] != GNU_PROPERTY_AARCH64_FEATURE_1_AND) return (false); /* We expect at least 4 bytes of data */ if (note_data[1] < 4) return (false); /* TODO: Only guard if HWCAP2_BTI is set */ if ((note_data[2] & GNU_PROPERTY_AARCH64_FEATURE_1_BTI) != 0) { struct arm64_guard_page_args guard; guard.addr = (uintptr_t)obj->mapbase; guard.len = obj->mapsize; sysarch(ARM64_GUARD_PAGE, &guard); } return (true); } void init_pltgot(Obj_Entry *obj) { if (obj->pltgot != NULL) { obj->pltgot[1] = (Elf_Addr) obj; obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; } } int do_copy_relocations(Obj_Entry *dstobj) { const Obj_Entry *srcobj, *defobj; const Elf_Rela *relalim; const Elf_Rela *rela; const Elf_Sym *srcsym; const Elf_Sym *dstsym; const void *srcaddr; const char *name; void *dstaddr; SymLook req; size_t size; int res; /* * COPY relocs are invalid outside of the main program */ assert(dstobj->mainprog); relalim = (const Elf_Rela *)((const char *)dstobj->rela + dstobj->relasize); for (rela = dstobj->rela; rela < relalim; rela++) { if (ELF_R_TYPE(rela->r_info) != R_AARCH64_COPY) continue; dstaddr = (void *)(dstobj->relocbase + rela->r_offset); dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info); name = dstobj->strtab + dstsym->st_name; size = dstsym->st_size; symlook_init(&req, name); req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info)); req.flags = SYMLOOK_EARLY; for (srcobj = globallist_next(dstobj); srcobj != NULL; srcobj = globallist_next(srcobj)) { res = symlook_obj(&req, srcobj); if (res == 0) { srcsym = req.sym_out; defobj = req.defobj_out; break; } } if (srcobj == NULL) { _rtld_error("Undefined symbol \"%s\" referenced from " "COPY relocation in %s", name, dstobj->path); return (-1); } srcaddr = (const void *)(defobj->relocbase + srcsym->st_value); memcpy(dstaddr, srcaddr, size); } return (0); } struct tls_data { Elf_Addr dtv_gen; int tls_index; Elf_Addr tls_offs; }; -static Elf_Addr +static struct tls_data * reloc_tlsdesc_alloc(int tlsindex, Elf_Addr tlsoffs) { struct tls_data *tlsdesc; tlsdesc = xmalloc(sizeof(struct tls_data)); tlsdesc->dtv_gen = tls_dtv_generation; tlsdesc->tls_index = tlsindex; tlsdesc->tls_offs = tlsoffs; - return ((Elf_Addr)tlsdesc); + return (tlsdesc); } +struct tlsdesc_entry { + void *(*func)(void *); + union { + Elf_Ssize addend; + Elf_Size offset; + struct tls_data *data; + }; +}; + static void -reloc_tlsdesc(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *where, - int flags, RtldLockState *lockstate) +reloc_tlsdesc(const Obj_Entry *obj, const Elf_Rela *rela, + struct tlsdesc_entry *where, int flags, RtldLockState *lockstate) { const Elf_Sym *def; const Obj_Entry *defobj; Elf_Addr offs; - offs = 0; if (ELF_R_SYM(rela->r_info) != 0) { def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, flags, NULL, lockstate); if (def == NULL) rtld_die(); offs = def->st_value; obj = defobj; if (def->st_shndx == SHN_UNDEF) { /* Weak undefined thread variable */ - where[0] = (Elf_Addr)_rtld_tlsdesc_undef; - where[1] = rela->r_addend; + where->func = _rtld_tlsdesc_undef; + where->addend = rela->r_addend; return; } } offs += rela->r_addend; if (obj->tlsoffset != 0) { /* Variable is in initialy allocated TLS segment */ - where[0] = (Elf_Addr)_rtld_tlsdesc_static; - where[1] = obj->tlsoffset + offs; + where->func = _rtld_tlsdesc_static; + where->offset = obj->tlsoffset + offs; } else { /* TLS offest is unknown at load time, use dynamic resolving */ - where[0] = (Elf_Addr)_rtld_tlsdesc_dynamic; - where[1] = reloc_tlsdesc_alloc(obj->tlsindex, offs); + where->func = _rtld_tlsdesc_dynamic; + where->data = reloc_tlsdesc_alloc(obj->tlsindex, offs); } } /* * Process the PLT relocations. */ int reloc_plt(Obj_Entry *obj, int flags, RtldLockState *lockstate) { const Obj_Entry *defobj; const Elf_Rela *relalim; const Elf_Rela *rela; const Elf_Sym *def, *sym; bool lazy; relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { Elf_Addr *where, target; where = (Elf_Addr *)(obj->relocbase + rela->r_offset); switch(ELF_R_TYPE(rela->r_info)) { case R_AARCH64_JUMP_SLOT: lazy = true; if (obj->variant_pcs) { sym = &obj->symtab[ELF_R_SYM(rela->r_info)]; /* * Variant PCS functions don't follow the * standard register convention. Because of * this we can't use lazy relocation and * need to set the target address. */ if ((sym->st_other & STO_AARCH64_VARIANT_PCS) != 0) lazy = false; } if (lazy) { *where += (Elf_Addr)obj->relocbase; } else { def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate); if (def == NULL) return (-1); if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC){ obj->gnu_ifunc = true; continue; } target = (Elf_Addr)(defobj->relocbase + def->st_value); /* * Ignore ld_bind_not as it requires lazy * binding */ *where = target; } break; case R_AARCH64_TLSDESC: - reloc_tlsdesc(obj, rela, where, SYMLOOK_IN_PLT | flags, - lockstate); + reloc_tlsdesc(obj, rela, (struct tlsdesc_entry *)where, + SYMLOOK_IN_PLT | flags, lockstate); break; case R_AARCH64_IRELATIVE: obj->irelative = true; break; case R_AARCH64_NONE: break; default: _rtld_error("Unknown relocation type %u in PLT", (unsigned int)ELF_R_TYPE(rela->r_info)); return (-1); } } return (0); } /* * LD_BIND_NOW was set - force relocation for all jump slots */ int reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate) { const Obj_Entry *defobj; const Elf_Rela *relalim; const Elf_Rela *rela; const Elf_Sym *def; if (obj->jmpslots_done) return (0); relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { Elf_Addr *where, target; where = (Elf_Addr *)(obj->relocbase + rela->r_offset); switch(ELF_R_TYPE(rela->r_info)) { case R_AARCH64_JUMP_SLOT: def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate); if (def == NULL) return (-1); if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { obj->gnu_ifunc = true; continue; } target = (Elf_Addr)(defobj->relocbase + def->st_value); reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela); break; } } obj->jmpslots_done = true; return (0); } static void reloc_iresolve_one(Obj_Entry *obj, const Elf_Rela *rela, RtldLockState *lockstate) { Elf_Addr *where, target, *ptr; ptr = (Elf_Addr *)(obj->relocbase + rela->r_addend); where = (Elf_Addr *)(obj->relocbase + rela->r_offset); lock_release(rtld_bind_lock, lockstate); target = call_ifunc_resolver(ptr); wlock_acquire(rtld_bind_lock, lockstate); *where = target; } int reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate) { const Elf_Rela *relalim; const Elf_Rela *rela; if (!obj->irelative) return (0); obj->irelative = false; relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { if (ELF_R_TYPE(rela->r_info) == R_AARCH64_IRELATIVE) reloc_iresolve_one(obj, rela, lockstate); } return (0); } int reloc_iresolve_nonplt(Obj_Entry *obj, struct Struct_RtldLockState *lockstate) { const Elf_Rela *relalim; const Elf_Rela *rela; if (!obj->irelative_nonplt) return (0); obj->irelative_nonplt = false; relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize); for (rela = obj->rela; rela < relalim; rela++) { if (ELF_R_TYPE(rela->r_info) == R_AARCH64_IRELATIVE) reloc_iresolve_one(obj, rela, lockstate); } return (0); } int reloc_gnu_ifunc(Obj_Entry *obj, int flags, struct Struct_RtldLockState *lockstate) { const Elf_Rela *relalim; const Elf_Rela *rela; Elf_Addr *where, target; const Elf_Sym *def; const Obj_Entry *defobj; if (!obj->gnu_ifunc) return (0); relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { if (ELF_R_TYPE(rela->r_info) == R_AARCH64_JUMP_SLOT) { where = (Elf_Addr *)(obj->relocbase + rela->r_offset); def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate); if (def == NULL) return (-1); if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC) continue; lock_release(rtld_bind_lock, lockstate); target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); wlock_acquire(rtld_bind_lock, lockstate); reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela); } } obj->gnu_ifunc = false; return (0); } Elf_Addr reloc_jmpslot(Elf_Addr *where, Elf_Addr target, const Obj_Entry *defobj __unused, const Obj_Entry *obj __unused, const Elf_Rel *rel) { assert(ELF_R_TYPE(rel->r_info) == R_AARCH64_JUMP_SLOT || ELF_R_TYPE(rel->r_info) == R_AARCH64_IRELATIVE); if (*where != target && !ld_bind_not) *where = target; return (target); } void ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused) { } /* * Process non-PLT relocations */ int reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags, RtldLockState *lockstate) { const Obj_Entry *defobj; const Elf_Rela *relalim; const Elf_Rela *rela; const Elf_Sym *def; SymCache *cache; Elf_Addr *where, symval; /* * The dynamic loader may be called from a thread, we have * limited amounts of stack available so we cannot use alloca(). */ if (obj == obj_rtld) cache = NULL; else cache = calloc(obj->dynsymcount, sizeof(SymCache)); /* No need to check for NULL here */ relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize); for (rela = obj->rela; rela < relalim; rela++) { /* * First, resolve symbol for relocations which * reference symbols. */ switch (ELF_R_TYPE(rela->r_info)) { case R_AARCH64_ABS64: case R_AARCH64_GLOB_DAT: case R_AARCH64_TLS_TPREL64: case R_AARCH64_TLS_DTPREL64: case R_AARCH64_TLS_DTPMOD64: def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, flags, cache, lockstate); if (def == NULL) return (-1); /* * If symbol is IFUNC, only perform relocation * when caller allowed it by passing * SYMLOOK_IFUNC flag. Skip the relocations * otherwise. * * Also error out in case IFUNC relocations * are specified for TLS, which cannot be * usefully interpreted. */ if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { switch (ELF_R_TYPE(rela->r_info)) { case R_AARCH64_ABS64: case R_AARCH64_GLOB_DAT: if ((flags & SYMLOOK_IFUNC) == 0) { obj->non_plt_gnu_ifunc = true; continue; } symval = (Elf_Addr)rtld_resolve_ifunc( defobj, def); break; default: _rtld_error("%s: IFUNC for TLS reloc", obj->path); return (-1); } } else { if ((flags & SYMLOOK_IFUNC) != 0) continue; symval = (Elf_Addr)defobj->relocbase + def->st_value; } break; default: if ((flags & SYMLOOK_IFUNC) != 0) continue; } where = (Elf_Addr *)(obj->relocbase + rela->r_offset); switch (ELF_R_TYPE(rela->r_info)) { case R_AARCH64_ABS64: case R_AARCH64_GLOB_DAT: *where = symval + rela->r_addend; break; case R_AARCH64_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->mainprog) { _rtld_error("%s: Unexpected R_AARCH64_COPY " "relocation in shared library", obj->path); return (-1); } break; case R_AARCH64_TLSDESC: - reloc_tlsdesc(obj, rela, where, flags, lockstate); + reloc_tlsdesc(obj, rela, (struct tlsdesc_entry *)where, + flags, lockstate); break; case R_AARCH64_TLS_TPREL64: /* * We lazily allocate offsets for static TLS as we * see the first relocation that references the * TLS block. This allows us to support (small * amounts of) static TLS in dynamically loaded * modules. If we run out of space, we generate an * error. */ if (!defobj->tls_static) { if (!allocate_tls_offset( __DECONST(Obj_Entry *, defobj))) { _rtld_error( "%s: No space available for static " "Thread Local Storage", obj->path); return (-1); } } *where = def->st_value + rela->r_addend + defobj->tlsoffset; break; /* * !!! BEWARE !!! * ARM ELF ABI defines TLS_DTPMOD64 as 1029, and TLS_DTPREL64 * as 1028. But actual bfd linker and the glibc RTLD linker * treats TLS_DTPMOD64 as 1028 and TLS_DTPREL64 1029. */ case R_AARCH64_TLS_DTPREL64: /* efectively is TLS_DTPMOD64 */ *where += (Elf_Addr)defobj->tlsindex; break; case R_AARCH64_TLS_DTPMOD64: /* efectively is TLS_DTPREL64 */ *where += (Elf_Addr)(def->st_value + rela->r_addend); break; case R_AARCH64_RELATIVE: *where = (Elf_Addr)(obj->relocbase + rela->r_addend); break; case R_AARCH64_NONE: break; case R_AARCH64_IRELATIVE: obj->irelative_nonplt = true; break; default: rtld_printf("%s: Unhandled relocation %lu\n", obj->path, ELF_R_TYPE(rela->r_info)); return (-1); } } return (0); } void allocate_initial_tls(Obj_Entry *objs) { /* * Fix the size of the static TLS block by using the maximum * offset allocated so far and adding a bit for dynamic modules to * use. */ tls_static_space = tls_last_offset + tls_last_size + ld_static_tls_extra; _tcb_set(allocate_tls(objs, NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN)); } void * __tls_get_addr(tls_index* ti) { uintptr_t **dtvp; dtvp = &_tcb_get()->tcb_dtv; return (tls_get_addr_common(dtvp, ti->ti_module, ti->ti_offset)); }