From patchwork Wed Nov 27 19:00:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Adhemerval Zanella (Code Review)" X-Patchwork-Id: 1201750 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-107440-incoming=patchwork.ozlabs.org@sourceware.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=gnutoolchain-gerrit.osci.io Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.b="Tmhh5cJA"; 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 47NVVF5lT2z9sTC for ; Thu, 28 Nov 2019 06:01:09 +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:date:from:to:subject:in-reply-to:references :reply-to:mime-version:content-transfer-encoding:content-type :message-id; q=dns; s=default; b=hI9vhKZdHhRDu7XFbjQ+vrnj6/xGj/3 s33qFlSPjd+HqHxTNjIeXl4hO9Yd1ZrkQDHYPqXb7DG2QuYJuv6TfFB0q64li6U5 w9SyfHQg40HIJpABarHeTlpIByp9OQ0M7q9UnJwUXwjSHRxcAe+556fv13FDHmtb yvDJTik8a2uA= 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:date:from:to:subject:in-reply-to:references :reply-to:mime-version:content-transfer-encoding:content-type :message-id; s=default; bh=a5xP0Lj8DvFkOk3dr7UqCLZA0Wo=; b=Tmhh5 cJAxAe6fTodGMaaR2egiGBu62uU/IqPIdFikf7qaMMbTt+SX5s83s8Cey7ad9xPb Au2/k1pqOkx8BgyeqsvvXlB60niBmVZVqK/r6VLssk52r7O43fvuDu2rdS0AyTyD hKWMJgjUOdvWoqZ8j7mXFq4Dt/TtEDAaRIsUH0= Received: (qmail 81648 invoked by alias); 27 Nov 2019 19:01:03 -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 81569 invoked by uid 89); 27 Nov 2019 19:01:02 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT autolearn=ham version=3.3.1 spammy= X-HELO: mx1.osci.io X-Gerrit-PatchSet: 5 Date: Wed, 27 Nov 2019 14:00:54 -0500 From: "Florian Weimer (Code Review)" To: Florian Weimer , Carlos O'Donell , libc-alpha@sourceware.org Auto-Submitted: auto-generated X-Gerrit-MessageType: newpatchset Subject: [review v5] Lazy binding failures during dlopen/dlclose must be fatal [BZ #24304] X-Gerrit-Change-Id: I6b1addfe2e30f50a1781595f046f44173db9491a X-Gerrit-Change-Number: 467 X-Gerrit-ChangeURL: X-Gerrit-Commit: af2b7eef272e46b82e8acc099b505c3dd06610fe In-Reply-To: References: Reply-To: fweimer@redhat.com, fweimer@redhat.com, libc-alpha@sourceware.org, carlos@redhat.com MIME-Version: 1.0 Content-Disposition: inline User-Agent: Gerrit/3.0.3-79-g83ff7f88f1 Message-Id: <20191127190055.5893620AF6@gnutoolchain-gerrit.osci.io> Change URL: https://gnutoolchain-gerrit.osci.io/r/c/glibc/+/467 ...................................................................... Lazy binding failures during dlopen/dlclose must be fatal [BZ #24304] If a lazy binding failure happens during the execution of an ELF constructor or destructor, the dynamic loader catches the error and reports it using the dlerror mechanism. This is undesirable because there could be other constructors and destructors that need processing (which are skipped), and the process is in an inconsistent state at this point. Therefore, we have to issue a fatal dynamic loader error error and terminate the process. Note that the _dl_catch_exception in _dl_open is just an inner catch, to roll back some state locally. If called from dlopen, there is still an outer catch, which is why calling _dl_init via call_dl_init and a no-exception is required and cannot be avoiding by moving the _dl_init call directly into _dl_open. _dl_fini does not need changes because it does not install an error handler, so errors are already fatal there. Change-Id: I6b1addfe2e30f50a1781595f046f44173db9491a --- M NEWS M elf/Makefile M elf/dl-close.c M elf/dl-open.c A elf/tst-finilazyfailmod.c A elf/tst-initfinilazyfail.c A elf/tst-initlazyfailmod.c 7 files changed, 216 insertions(+), 21 deletions(-) diff --git a/NEWS b/NEWS index 4e28dc4..a62930f 100644 --- a/NEWS +++ b/NEWS @@ -84,6 +84,12 @@ are no longer supported. For v8 only implementations with native CAS instruction are still supported (such as LEON). +* If a lazy binding failure happens during dlopen, during the execution of + an ELF constructor, the process is now terminated. Previously, the + dynamic loader would return NULL from dlopen, with the lazy binding error + captured in a dlerror message. In general, this is unsafe because + resetting the stack in an arbitrary function call is not possible. + Changes to build and runtime requirements: [Add changes to build and runtime requirements here] diff --git a/elf/Makefile b/elf/Makefile index b05af5c..30c3896 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -199,7 +199,7 @@ tst-debug1 tst-main1 tst-absolute-sym tst-absolute-zero tst-big-note \ tst-unwind-ctor tst-unwind-main tst-audit13 \ tst-sonamemove-link tst-sonamemove-dlopen tst-dlopen-tlsmodid \ - tst-dlopen-self tst-auditmany + tst-dlopen-self tst-auditmany tst-initfinilazyfail # reldep9 tests-internal += loadtest unload unload2 circleload1 \ neededtest neededtest2 neededtest3 neededtest4 \ @@ -290,7 +290,8 @@ tst-sonamemove-runmod1 tst-sonamemove-runmod2 \ tst-auditmanymod1 tst-auditmanymod2 tst-auditmanymod3 \ tst-auditmanymod4 tst-auditmanymod5 tst-auditmanymod6 \ - tst-auditmanymod7 tst-auditmanymod8 tst-auditmanymod9 + tst-auditmanymod7 tst-auditmanymod8 tst-auditmanymod9 \ + tst-initlazyfailmod tst-finilazyfailmod # Most modules build with _ISOMAC defined, but those filtered out # depend on internal headers. modules-names-tests = $(filter-out ifuncmod% tst-libc_dlvsym-dso tst-tlsmod%,\ @@ -1586,3 +1587,13 @@ $(objpfx)tst-unwind-ctor: $(objpfx)tst-unwind-ctor-lib.so CFLAGS-tst-unwind-main.c += -funwind-tables -DUSE_PTHREADS=0 + +$(objpfx)tst-initfinilazyfail: $(libdl) +$(objpfx)tst-initfinilazyfail.out: \ + $(objpfx)tst-initlazyfailmod.so $(objpfx)tst-finilazyfailmod.so +# Override -z defs, so that we can reference an undefined symbol. +# Force lazy binding for the same reason. +LDFLAGS-tst-initlazyfailmod.so = \ + -Wl,-z,lazy -Wl,--unresolved-symbols=ignore-all +LDFLAGS-tst-finilazyfailmod.so = \ + -Wl,-z,lazy -Wl,--unresolved-symbols=ignore-all diff --git a/elf/dl-close.c b/elf/dl-close.c index c32e647..33486b9 100644 --- a/elf/dl-close.c +++ b/elf/dl-close.c @@ -106,6 +106,30 @@ return false; } +/* Invoke dstructors for CLOSURE (a struct link_map *). Called with + exception handling temporarily disabled, to make errors fatal. */ +static void +call_destructors (void *closure) +{ + struct link_map *map = closure; + + if (map->l_info[DT_FINI_ARRAY] != NULL) + { + ElfW(Addr) *array = + (ElfW(Addr) *) (map->l_addr + + map->l_info[DT_FINI_ARRAY]->d_un.d_ptr); + unsigned int sz = (map->l_info[DT_FINI_ARRAYSZ]->d_un.d_val + / sizeof (ElfW(Addr))); + + while (sz-- > 0) + ((fini_t) array[sz]) (); + } + + /* Next try the old-style destructor. */ + if (map->l_info[DT_FINI] != NULL) + DL_CALL_DT_FINI (map, ((void *) map->l_addr + + map->l_info[DT_FINI]->d_un.d_ptr)); +} void _dl_close_worker (struct link_map *map, bool force) @@ -267,7 +291,8 @@ && (imap->l_flags_1 & DF_1_NODELETE) == 0); /* Call its termination function. Do not do it for - half-cooked objects. */ + half-cooked objects. Temporarily disable exception + handling, so that errors are fatal. */ if (imap->l_init_called) { /* When debugging print a message first. */ @@ -276,22 +301,9 @@ _dl_debug_printf ("\ncalling fini: %s [%lu]\n\n", imap->l_name, nsid); - if (imap->l_info[DT_FINI_ARRAY] != NULL) - { - ElfW(Addr) *array = - (ElfW(Addr) *) (imap->l_addr - + imap->l_info[DT_FINI_ARRAY]->d_un.d_ptr); - unsigned int sz = (imap->l_info[DT_FINI_ARRAYSZ]->d_un.d_val - / sizeof (ElfW(Addr))); - - while (sz-- > 0) - ((fini_t) array[sz]) (); - } - - /* Next try the old-style destructor. */ - if (imap->l_info[DT_FINI] != NULL) - DL_CALL_DT_FINI (imap, ((void *) imap->l_addr - + imap->l_info[DT_FINI]->d_un.d_ptr)); + if (imap->l_info[DT_FINI_ARRAY] != NULL + || imap->l_info[DT_FINI] != NULL) + _dl_catch_exception (NULL, call_destructors, imap); } #ifdef SHARED diff --git a/elf/dl-open.c b/elf/dl-open.c index 8d699d3..533fb96 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -177,6 +177,23 @@ } rtld_hidden_def (_dl_find_dso_for_object); +/* struct dl_init_args and call_dl_init are used to call _dl_init with + exception handling disabled. */ +struct dl_init_args +{ + struct link_map *new; + int argc; + char **argv; + char **env; +}; + +static void +call_dl_init (void *closure) +{ + struct dl_init_args *args = closure; + _dl_init (args->new, args->argc, args->argv, args->env); +} + static void dl_open_worker (void *a) { @@ -509,8 +526,19 @@ DL_STATIC_INIT (new); #endif - /* Run the initializer functions of new objects. */ - _dl_init (new, args->argc, args->argv, args->env); + /* Run the initializer functions of new objects. Temporarily + disable the exception handler, so that lazy binding failures are + fatal. */ + { + struct dl_init_args init_args = + { + .new = new, + .argc = args->argc, + .argv = args->argv, + .env = args->env + }; + _dl_catch_exception (NULL, call_dl_init, &init_args); + } /* Now we can make the new map available in the global scope. */ if (mode & RTLD_GLOBAL) diff --git a/elf/tst-finilazyfailmod.c b/elf/tst-finilazyfailmod.c new file mode 100644 index 0000000..2670bd1 --- /dev/null +++ b/elf/tst-finilazyfailmod.c @@ -0,0 +1,27 @@ +/* Helper module for tst-initfinilazyfail: lazy binding failure in destructor. + Copyright (C) 2019 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 + . */ + +/* An undefined function. Calling it will cause a lazy binding + failure. */ +void undefined_function (void); + +static void __attribute__ ((destructor)) +fini (void) +{ + undefined_function (); +} diff --git a/elf/tst-initfinilazyfail.c b/elf/tst-initfinilazyfail.c new file mode 100644 index 0000000..9b4a3d0 --- /dev/null +++ b/elf/tst-initfinilazyfail.c @@ -0,0 +1,84 @@ +/* Test that lazy binding failures in constructors and destructors are fatal. + Copyright (C) 2019 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 + . */ + +#include +#include +#include +#include +#include + +static void +test_constructor (void *closure) +{ + void *handle = dlopen ("tst-initlazyfailmod.so", RTLD_LAZY); + if (handle == NULL) + FAIL_EXIT (2, "dlopen did not terminate the process: %s", dlerror ()); + else + FAIL_EXIT (2, "dlopen did not terminate the process (%p)", handle); +} + +static void +test_destructor (void *closure) +{ + void *handle = xdlopen ("tst-finilazyfailmod.so", RTLD_LAZY); + int ret = dlclose (handle); + const char *message = dlerror (); + if (message != NULL) + FAIL_EXIT (2, "dlclose did not terminate the process: %d, %s", + ret, message); + else + FAIL_EXIT (2, "dlopen did not terminate the process: %d", ret); +} + +static int +do_test (void) +{ + { + struct support_capture_subprocess proc + = support_capture_subprocess (test_constructor, NULL); + support_capture_subprocess_check (&proc, "constructor", 127, + sc_allow_stderr); + printf ("info: constructor failure output: [[%s]]\n", proc.err.buffer); + TEST_VERIFY (strstr (proc.err.buffer, + "tst-initfinilazyfail: symbol lookup error: ") + != NULL); + TEST_VERIFY (strstr (proc.err.buffer, + "tst-initlazyfailmod.so: undefined symbol:" + " undefined_function\n") != NULL); + support_capture_subprocess_free (&proc); + } + + { + struct support_capture_subprocess proc + = support_capture_subprocess (test_destructor, NULL); + support_capture_subprocess_check (&proc, "destructor", 127, + sc_allow_stderr); + printf ("info: destructor failure output: [[%s]]\n", proc.err.buffer); + TEST_VERIFY (strstr (proc.err.buffer, + "tst-initfinilazyfail: symbol lookup error: ") + != NULL); + TEST_VERIFY (strstr (proc.err.buffer, + "tst-finilazyfailmod.so: undefined symbol:" + " undefined_function\n") != NULL); + support_capture_subprocess_free (&proc); + } + + return 0; +} + +#include diff --git a/elf/tst-initlazyfailmod.c b/elf/tst-initlazyfailmod.c new file mode 100644 index 0000000..36348b5 --- /dev/null +++ b/elf/tst-initlazyfailmod.c @@ -0,0 +1,27 @@ +/* Helper module for tst-initfinilazyfail: lazy binding failure in constructor. + Copyright (C) 2019 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 + . */ + +/* An undefined function. Calling it will cause a lazy binding + failure. */ +void undefined_function (void); + +static void __attribute__ ((constructor)) +init (void) +{ + undefined_function (); +}