From patchwork Sat Feb 8 19:01:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 1235359 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=209.132.180.131; helo=sourceware.org; envelope-from=libc-alpha-return-109272-incoming=patchwork.ozlabs.org@sourceware.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.a=rsa-sha1 header.s=default header.b=TZBCBqC2; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=btvwqbN2; dkim-atps=neutral Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 48FM2w214Hz9sPJ for ; Sun, 9 Feb 2020 06:01:28 +1100 (AEDT) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:subject:in-reply-to:references :message-id:date:mime-version:content-type :content-transfer-encoding; q=dns; s=default; b=TSC/99ubKxzVqoCm U81OV70aCqzKEWzbZxJKky2GGuXjqPIfK9plPnikVRri4gxCPAoSD/ya0+T/NU2x pLVSeh3DHEl0Mg8AVPlY7gOgqmjG9HZtBXD+BfNBogtk1JEvAwsIU2QZ9cXKo77s VanTSf8xePwQDS8j07cRjNOgvGs= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:subject:in-reply-to:references :message-id:date:mime-version:content-type :content-transfer-encoding; s=default; bh=OOiLh2PYPxKBK+TovP7Gw6 ydd2c=; b=TZBCBqC2ivk2IxOjEDSmKHzeieYG/QEZlleAvzjue9o2Gw+ex1qo4v l1fwUS0gYQt2g3rOg9WAA3Nsk9nf6IiNH1fLUMk16lZqe0P8QhRd5vzToEPoI0UF rMEFDfuWTrmGE96LCoGAVGiSOB1fjyh5644vyvguFpyCPVqFc1XTA= Received: (qmail 67167 invoked by alias); 8 Feb 2020 19:01:16 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 67104 invoked by uid 89); 8 Feb 2020 19:01:16 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-18.0 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, KAM_STOCKGEN, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 spammy=Auditing, auditing X-HELO: us-smtp-delivery-1.mimecast.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581188472; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DHZ1+5syt4FYsdT0jjbiphEcmBeJxOfn4ao29fjpt8U=; b=btvwqbN2SuKTa2FhNcFFoFOdKDE2bak6/reW5HI/dyqa+Psqbo5ES2HvCMiXY0C/fG9Vrf aFpUypVgRaIa8uOcBU1Tc9bR8mN5CJg+5e3AM2Tu/g74FZbZt81/yzAZ/ZL5yYV3E2vmPh jolzESn/DwW2wp2bVJZfweQ4TfcBhOo= From: Florian Weimer To: libc-alpha@sourceware.org Subject: [PATCH 2/4] elf: Extract _dl_sym_post, _dl_sym_find_caller_map from elf/dl-sym.c In-Reply-To: References: Message-Id: <68608ef426b88e73e0e3178497bcfe34dd8a66ef.1581182210.git.fweimer@redhat.com> Date: Sat, 08 Feb 2020 20:01:04 +0100 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com The definitions are moved into a new file, elf/dl-sym-post.h, so that this code can be used by the dynamic loader as well. Reviewed-by: Carlos O'Donell --- elf/dl-sym-post.h | 106 ++++++++++++++++++++++++++++++++++++++++++++++ elf/dl-sym.c | 86 ++----------------------------------- 2 files changed, 110 insertions(+), 82 deletions(-) create mode 100644 elf/dl-sym-post.h diff --git a/elf/dl-sym-post.h b/elf/dl-sym-post.h new file mode 100644 index 0000000000..4c4f574633 --- /dev/null +++ b/elf/dl-sym-post.h @@ -0,0 +1,106 @@ +/* Post-processing of a symbol produced by dlsym, dlvsym. + Copyright (C) 1999-2020 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + + +/* Return the link map containing the caller address. */ +static struct link_map * +_dl_sym_find_caller_link_map (ElfW(Addr) caller) +{ + struct link_map *l = _dl_find_dso_for_object (caller); + if (l != NULL) + return l; + else + /* If the address is not recognized the call comes from the main + program (we hope). */ + return GL(dl_ns)[LM_ID_BASE]._ns_loaded; +} + +/* Translates RESULT, *REF, VALUE into a symbol address from the point + of view of MATCH. Performs IFUNC resolution and auditing if + necessary. If MATCH is NULL, CALLER is used to determine it. */ +static void * +_dl_sym_post (lookup_t result, const ElfW(Sym) *ref, void *value, + ElfW(Addr) caller, struct link_map *match) +{ + /* Resolve indirect function address. */ + if (__glibc_unlikely (ELFW(ST_TYPE) (ref->st_info) == STT_GNU_IFUNC)) + { + DL_FIXUP_VALUE_TYPE fixup + = DL_FIXUP_MAKE_VALUE (result, (ElfW(Addr)) value); + fixup = elf_ifunc_invoke (DL_FIXUP_VALUE_ADDR (fixup)); + value = (void *) DL_FIXUP_VALUE_CODE_ADDR (fixup); + } + +#ifdef SHARED + /* Auditing checkpoint: we have a new binding. Provide the + auditing libraries the possibility to change the value and + tell us whether further auditing is wanted. */ + if (__glibc_unlikely (GLRO(dl_naudit) > 0)) + { + const char *strtab = (const char *) D_PTR (result, + l_info[DT_STRTAB]); + /* Compute index of the symbol entry in the symbol table of + the DSO with the definition. */ + unsigned int ndx = (ref - (ElfW(Sym) *) D_PTR (result, + l_info[DT_SYMTAB])); + + if (match == NULL) + match = _dl_sym_find_caller_link_map (caller); + + if ((match->l_audit_any_plt | result->l_audit_any_plt) != 0) + { + unsigned int altvalue = 0; + struct audit_ifaces *afct = GLRO(dl_audit); + /* Synthesize a symbol record where the st_value field is + the result. */ + ElfW(Sym) sym = *ref; + sym.st_value = (ElfW(Addr)) value; + + for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) + { + struct auditstate *match_audit + = link_map_audit_state (match, cnt); + struct auditstate *result_audit + = link_map_audit_state (result, cnt); + if (afct->symbind != NULL + && ((match_audit->bindflags & LA_FLG_BINDFROM) != 0 + || ((result_audit->bindflags & LA_FLG_BINDTO) + != 0))) + { + unsigned int flags = altvalue | LA_SYMB_DLSYM; + uintptr_t new_value + = afct->symbind (&sym, ndx, + &match_audit->cookie, + &result_audit->cookie, + &flags, strtab + ref->st_name); + if (new_value != (uintptr_t) sym.st_value) + { + altvalue = LA_SYMB_ALTVALUE; + sym.st_value = new_value; + } + } + + afct = afct->next; + } + + value = (void *) sym.st_value; + } + } +#endif + return value; +} diff --git a/elf/dl-sym.c b/elf/dl-sym.c index b43a50e544..361b926ea9 100644 --- a/elf/dl-sym.c +++ b/elf/dl-sym.c @@ -28,6 +28,7 @@ #include #include #include +#include #ifdef SHARED @@ -80,19 +81,6 @@ call_dl_lookup (void *ptr) args->flags, NULL); } -/* Return the link map containing the caller address. */ -static inline struct link_map * -find_caller_link_map (ElfW(Addr) caller) -{ - struct link_map *l = _dl_find_dso_for_object (caller); - if (l != NULL) - return l; - else - /* If the address is not recognized the call comes from the main - program (we hope). */ - return GL(dl_ns)[LM_ID_BASE]._ns_loaded; -} - static void * do_sym (void *handle, const char *name, void *who, struct r_found_version *vers, int flags) @@ -106,7 +94,7 @@ do_sym (void *handle, const char *name, void *who, if (handle == RTLD_DEFAULT) { - match = find_caller_link_map (caller); + match = _dl_sym_find_caller_link_map (caller); /* Search the global scope. We have the simple case where we look up in the scope of an object which was part of @@ -140,7 +128,7 @@ do_sym (void *handle, const char *name, void *who, } else if (handle == RTLD_NEXT) { - match = find_caller_link_map (caller); + match = _dl_sym_find_caller_link_map (caller); if (__glibc_unlikely (match == GL(dl_ns)[LM_ID_BASE]._ns_loaded)) { @@ -179,73 +167,7 @@ RTLD_NEXT used in code not dynamically loaded")); #endif value = DL_SYMBOL_ADDRESS (result, ref); - /* Resolve indirect function address. */ - if (__glibc_unlikely (ELFW(ST_TYPE) (ref->st_info) == STT_GNU_IFUNC)) - { - DL_FIXUP_VALUE_TYPE fixup - = DL_FIXUP_MAKE_VALUE (result, (ElfW(Addr)) value); - fixup = elf_ifunc_invoke (DL_FIXUP_VALUE_ADDR (fixup)); - value = (void *) DL_FIXUP_VALUE_CODE_ADDR (fixup); - } - -#ifdef SHARED - /* Auditing checkpoint: we have a new binding. Provide the - auditing libraries the possibility to change the value and - tell us whether further auditing is wanted. */ - if (__glibc_unlikely (GLRO(dl_naudit) > 0)) - { - const char *strtab = (const char *) D_PTR (result, - l_info[DT_STRTAB]); - /* Compute index of the symbol entry in the symbol table of - the DSO with the definition. */ - unsigned int ndx = (ref - (ElfW(Sym) *) D_PTR (result, - l_info[DT_SYMTAB])); - - if (match == NULL) - match = find_caller_link_map (caller); - - if ((match->l_audit_any_plt | result->l_audit_any_plt) != 0) - { - unsigned int altvalue = 0; - struct audit_ifaces *afct = GLRO(dl_audit); - /* Synthesize a symbol record where the st_value field is - the result. */ - ElfW(Sym) sym = *ref; - sym.st_value = (ElfW(Addr)) value; - - for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) - { - struct auditstate *match_audit - = link_map_audit_state (match, cnt); - struct auditstate *result_audit - = link_map_audit_state (result, cnt); - if (afct->symbind != NULL - && ((match_audit->bindflags & LA_FLG_BINDFROM) != 0 - || ((result_audit->bindflags & LA_FLG_BINDTO) - != 0))) - { - unsigned int flags = altvalue | LA_SYMB_DLSYM; - uintptr_t new_value - = afct->symbind (&sym, ndx, - &match_audit->cookie, - &result_audit->cookie, - &flags, strtab + ref->st_name); - if (new_value != (uintptr_t) sym.st_value) - { - altvalue = LA_SYMB_ALTVALUE; - sym.st_value = new_value; - } - } - - afct = afct->next; - } - - value = (void *) sym.st_value; - } - } -#endif - - return value; + return _dl_sym_post (result, ref, value, caller, match); } return NULL;