From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTP id D692E398B8A1 for ; Wed, 9 Jun 2021 15:25:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org D692E398B8A1 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-428-ZPeVyfJWNsOMU-hQnPdirQ-1; Wed, 09 Jun 2021 11:25:12 -0400 X-MC-Unique: ZPeVyfJWNsOMU-hQnPdirQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 804E0185060F for ; Wed, 9 Jun 2021 15:25:10 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-115-60.ams2.redhat.com [10.36.115.60]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C6C1660853 for ; Wed, 9 Jun 2021 15:25:09 +0000 (UTC) From: Florian Weimer To: libc-stable@sourceware.org Subject: [COMMITTED 2.33] dlfcn: Failures after dlmopen should not terminate process [BZ #15271] Date: Wed, 09 Jun 2021 17:25:08 +0200 Message-ID: <87sg1r3vsb.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-11.9 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP, URIBL_BLACK autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-stable@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-stable mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Jun 2021 15:25:27 -0000 Commit 9e78f6f6e7134a5f299cc8de77370218f8019237 ("Implement _dl_catch_error, _dl_signal_error in libc.so [BZ #16628]") has the side effect that distinct namespaces, as created by dlmopen, now have separate implementations of the rtld exception mechanism. This means that the call to _dl_catch_error from libdl in a secondary namespace does not actually install an exception handler because the thread-local variable catch_hook in the libc.so copy in the secondary namespace is distinct from that of the base namepace. As a result, a dlsym/dlopen/... failure in a secondary namespace terminates the process with a dynamic linker error because it looks to the exception handler mechanism as if no handler has been installed. Backport notes: GLRO (dl_catch_error) is replaced with _dl_catch_error_ptr to preserve _rtld_global_ro layout. (cherry picked from commit b2964eb1d9a6b8ab1250e8a881cf406182da5875) --- NEWS | 1 + dlfcn/dlerror.c | 13 +++++++++++-- elf/Makefile | 8 +++++++- elf/Versions | 2 +- elf/dl-error-skeleton.c | 15 +++++++++++++++ elf/rtld.c | 1 - elf/tst-dlmopen-dlerror-mod.c | 41 +++++++++++++++++++++++++++++++++++++++++ elf/tst-dlmopen-dlerror.c | 37 +++++++++++++++++++++++++++++++++++++ sysdeps/generic/ldsodefs.h | 11 +++++++++++ 9 files changed, 124 insertions(+), 5 deletions(-) diff --git a/NEWS b/NEWS index a6202ad058..0c33a80af9 100644 --- a/NEWS +++ b/NEWS @@ -15,6 +15,7 @@ Major new features: The following bugs are resolved with this release: + [15271] dlfcn function failure after dlmopen terminates process [18435] pthread_once hangs when init routine throws an exception [23462] Static binary with dynamic string tokens ($LIB, $PLATFORM, $ORIGIN) crashes diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c index 48b4c25bea..ff7c7b9228 100644 --- a/dlfcn/dlerror.c +++ b/dlfcn/dlerror.c @@ -167,8 +167,17 @@ _dlerror_run (void (*operate) (void *), void *args) result->errstring = NULL; } - result->errcode = _dl_catch_error (&result->objname, &result->errstring, - &result->malloced, operate, args); +#ifdef SHARED + result->errcode = _dl_catch_error_ptr (&result->objname, + &result->errstring, + &result->malloced, + operate, args); +#else + result->errcode = _dl_catch_error (&result->objname, + &result->errstring, + &result->malloced, + operate, args); +#endif /* If no error we mark that no error string is available. */ result->returned = result->errstring == NULL; diff --git a/elf/Makefile b/elf/Makefile index 28e18aea5d..509475dd99 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -226,7 +226,8 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \ tst-audit14 tst-audit15 tst-audit16 \ tst-single_threaded tst-single_threaded-pthread \ tst-tls-ie tst-tls-ie-dlmopen argv0test \ - tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask + tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \ + tst-dlmopen-dlerror # reldep9 tests-internal += loadtest unload unload2 circleload1 \ neededtest neededtest2 neededtest3 neededtest4 \ @@ -348,6 +349,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ libmarkermod2-1 libmarkermod2-2 \ libmarkermod3-1 libmarkermod3-2 libmarkermod3-3 \ libmarkermod4-1 libmarkermod4-2 libmarkermod4-3 libmarkermod4-4 \ + tst-dlmopen-dlerror-mod \ # Most modules build with _ISOMAC defined, but those filtered out # depend on internal headers. @@ -1583,6 +1585,10 @@ $(objpfx)tst-sonamemove-dlopen.out: \ $(objpfx)tst-sonamemove-runmod1.so \ $(objpfx)tst-sonamemove-runmod2.so +$(objpfx)tst-dlmopen-dlerror: $(libdl) +$(objpfx)tst-dlmopen-dlerror-mod.so: $(libdl) $(libsupport) +$(objpfx)tst-dlmopen-dlerror.out: $(objpfx)tst-dlmopen-dlerror-mod.so + # Override -z defs, so that we can reference an undefined symbol. # Force lazy binding for the same reason. LDFLAGS-tst-latepthreadmod.so = \ diff --git a/elf/Versions b/elf/Versions index be88c48e6d..cdfd7b4d2f 100644 --- a/elf/Versions +++ b/elf/Versions @@ -72,7 +72,7 @@ ld { # Internal error handling support. Interposed by libc.so. _dl_signal_exception; _dl_catch_exception; - _dl_signal_error; _dl_catch_error; + _dl_signal_error; _dl_catch_error; _dl_catch_error_ptr; # Set value of a tunable. __tunable_get_val; diff --git a/elf/dl-error-skeleton.c b/elf/dl-error-skeleton.c index 2fd62777cf..0de505f258 100644 --- a/elf/dl-error-skeleton.c +++ b/elf/dl-error-skeleton.c @@ -248,4 +248,19 @@ _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args) catch_hook = old_catch; receiver = old_receiver; } + +/* Forwarder used for initializing _dl_catch_error_ptr. */ +int +_rtld_catch_error (const char **objname, const char **errstring, + bool *mallocedp, void (*operate) (void *), + void *args) +{ + /* The reference to _dl_catch_error will eventually be relocated to + point to the implementation in libc.so. */ + return _dl_catch_error (objname, errstring, mallocedp, operate, args); +} + +__typeof (_dl_catch_error) *_dl_catch_error_ptr = _rtld_catch_error; +rtld_hidden_data_def (_dl_catch_error_ptr); + #endif /* DL_ERROR_BOOTSTRAP */ diff --git a/elf/rtld.c b/elf/rtld.c index 94a00e2049..489e58c551 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -380,7 +380,6 @@ struct rtld_global_ro _rtld_global_ro attribute_relro = extern struct rtld_global_ro _rtld_local_ro __attribute__ ((alias ("_rtld_global_ro"), visibility ("hidden"))); - static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum, ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv); diff --git a/elf/tst-dlmopen-dlerror-mod.c b/elf/tst-dlmopen-dlerror-mod.c new file mode 100644 index 0000000000..7e95dcdeac --- /dev/null +++ b/elf/tst-dlmopen-dlerror-mod.c @@ -0,0 +1,41 @@ +/* Check that dlfcn errors are reported properly after dlmopen. Test module. + Copyright (C) 2021 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 + +/* Note: This object is not linked into the main program, so we cannot + use delayed test failure reporting via TEST_VERIFY etc., and have + to use FAIL_EXIT1 (or something else that calls exit). */ + +void +call_dlsym (void) +{ + void *ptr = dlsym (NULL, "does not exist"); + if (ptr != NULL) + FAIL_EXIT1 ("dlsym did not fail as expected"); +} + +void +call_dlopen (void) +{ + void *handle = dlopen ("tst-dlmopen-dlerror does not exist", RTLD_NOW); + if (handle != NULL) + FAIL_EXIT1 ("dlopen did not fail as expected"); +} diff --git a/elf/tst-dlmopen-dlerror.c b/elf/tst-dlmopen-dlerror.c new file mode 100644 index 0000000000..e864d2fe4c --- /dev/null +++ b/elf/tst-dlmopen-dlerror.c @@ -0,0 +1,37 @@ +/* Check that dlfcn errors are reported properly after dlmopen. + Copyright (C) 2021 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 + +static int +do_test (void) +{ + void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-dlerror-mod.so", + RTLD_NOW); + void (*call_dlsym) (void) = xdlsym (handle, "call_dlsym"); + void (*call_dlopen) (void) = xdlsym (handle, "call_dlopen"); + + call_dlsym (); + call_dlopen (); + + return 0; +} + +#include diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index aab7245e93..d552a7886b 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -893,6 +893,17 @@ extern int _dl_catch_error (const char **objname, const char **errstring, void *args); libc_hidden_proto (_dl_catch_error) + +/* libdl in a secondary namespace (after dlopen) must use + _dl_catch_error from the main namespace, so it has to be exported + in some way. Initialized to _rtld_catch_error in rtld.c. Not in + _rtld_global_ro to preserve structure layout. */ +extern __typeof (_dl_catch_error) *_dl_catch_error_ptr attribute_relro; +rtld_hidden_proto (_dl_catch_error_ptr) + +/* Used for initializing _dl_catch_error_ptr. */ +extern __typeof__ (_dl_catch_error) _rtld_catch_error attribute_hidden; + /* Call OPERATE (ARGS). If no error occurs, set *EXCEPTION to zero. Otherwise, store a copy of the raised exception in *EXCEPTION, which has to be freed by _dl_exception_free. As a special case, if