From patchwork Thu Oct 31 19:20:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Simon Marchi (Code Review)" X-Patchwork-Id: 35524 Received: (qmail 120444 invoked by alias); 31 Oct 2019 19:20:54 -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 120381 invoked by uid 89); 31 Oct 2019 19:20:53 -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=roll, l_addr X-HELO: mx1.osci.io X-Gerrit-PatchSet: 1 Date: Thu, 31 Oct 2019 15:20:40 -0400 From: "Florian Weimer (Code Review)" To: libc-alpha@sourceware.org Cc: Florian Weimer Message-ID: Auto-Submitted: auto-generated X-Gerrit-MessageType: newchange Subject: [review] 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: 4f9d0f27d9cd520c3cb42905611d7155c03964cd References: Reply-To: fweimer@redhat.com, fweimer@redhat.com, libc-alpha@sourceware.org MIME-Version: 1.0 Content-Disposition: inline User-Agent: Gerrit/3.0.3-75-g9005159e5d 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 Reviewed-by: Carlos O'Donell Reviewed-by: Carlos O'Donell --- 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 6 files changed, 210 insertions(+), 21 deletions(-) diff --git a/elf/Makefile b/elf/Makefile index 5e4cdb4..a09b650 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -193,7 +193,7 @@ 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-dlopen-self tst-initfinilazyfail # reldep9 tests-internal += loadtest unload unload2 circleload1 \ neededtest neededtest2 neededtest3 neededtest4 \ @@ -281,7 +281,8 @@ tst-main1mod tst-libc_dlvsym-dso tst-absolute-sym-lib \ tst-absolute-zero-lib tst-big-note-lib tst-unwind-ctor-lib \ tst-audit13mod1 tst-sonamemove-linkmod1 \ - tst-sonamemove-runmod1 tst-sonamemove-runmod2 + tst-sonamemove-runmod1 tst-sonamemove-runmod2 \ + 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%,\ @@ -1569,3 +1570,13 @@ $(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 de91c28..2e38943 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 cc802fd..aad22ef 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -214,6 +214,23 @@ } 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) { @@ -555,8 +572,19 @@ if (mode & RTLD_GLOBAL) add_to_global_resize (new); - /* 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 (); +}