From patchwork Mon Mar 15 11:18:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 42541 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id A796C3858D33; Mon, 15 Mar 2021 11:18:30 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A796C3858D33 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1615807110; bh=LS0tR27OxITpU2za5GnkrMT8+5dHLlclh2bNf5q+2/k=; h=To:Subject:In-Reply-To:References:Date:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=FEskepruxVpYgQnQyKYaLs14QYCqeHzfBcUVckOT3flXyPbUq4a9gdeJR41iWIrGX Sx5si1Awg3wBHPSYKH5RN7pdRAs9BOhcWJZX6knNgGqZbRwf45tMWOvLUIrTq5lUs0 v1k3zvgUg+SZHDT8Xmu7Y3nkRRg8i3l3GPrZYChU= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 932C23858D29 for ; Mon, 15 Mar 2021 11:18:27 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 932C23858D29 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-407-WtUnj29FNjKGarvnzqn_FQ-1; Mon, 15 Mar 2021 07:18:23 -0400 X-MC-Unique: WtUnj29FNjKGarvnzqn_FQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0CBBCCC622 for ; Mon, 15 Mar 2021 11:18:22 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-163.ams2.redhat.com [10.36.112.163]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2FBC1100164C for ; Mon, 15 Mar 2021 11:18:21 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH 1/2] dlfcn: Failures after dlmopen should not terminate process [BZ #24772] In-Reply-To: References: Message-Id: <038ee59a44a4546933eea91a3db974e6e1d2ac91.1615806966.git.fweimer@redhat.com> Date: Mon, 15 Mar 2021 12:18:27 +0100 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-11.7 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_H3, 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-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" 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. This commit restores GLRO (dl_catch_error) and uses it to set the handler in the base namespace. --- dlfcn/dlerror.c | 6 +++-- elf/Makefile | 8 ++++++- elf/dl-error-skeleton.c | 12 ++++++++++ elf/rtld.c | 1 + elf/tst-dlmopen-dlerror-mod.c | 41 +++++++++++++++++++++++++++++++++++ elf/tst-dlmopen-dlerror.c | 37 +++++++++++++++++++++++++++++++ sysdeps/generic/ldsodefs.h | 9 ++++++++ 7 files changed, 111 insertions(+), 3 deletions(-) create mode 100644 elf/tst-dlmopen-dlerror-mod.c create mode 100644 elf/tst-dlmopen-dlerror.c diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c index 48b4c25bea..947b7c10c6 100644 --- a/dlfcn/dlerror.c +++ b/dlfcn/dlerror.c @@ -167,8 +167,10 @@ _dlerror_run (void (*operate) (void *), void *args) result->errstring = NULL; } - result->errcode = _dl_catch_error (&result->objname, &result->errstring, - &result->malloced, operate, args); + result->errcode = GLRO (dl_catch_error) (&result->objname, + &result->errstring, + &result->malloced, + operate, args); /* 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 4c9e63dac9..7e0a85df49 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-ldconfig-ld-mod tst-dlmopen-dlerror-mod \ # Most modules build with _ISOMAC defined, but those filtered out # depend on internal headers. @@ -1581,6 +1583,10 @@ $(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/dl-error-skeleton.c b/elf/dl-error-skeleton.c index 2fd62777cf..b699936c6e 100644 --- a/elf/dl-error-skeleton.c +++ b/elf/dl-error-skeleton.c @@ -248,4 +248,16 @@ _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args) catch_hook = old_catch; receiver = old_receiver; } + +/* Forwarder used for initializing GLRO (_dl_catch_error). */ +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); +} + #endif /* DL_ERROR_BOOTSTRAP */ diff --git a/elf/rtld.c b/elf/rtld.c index 94a00e2049..fd02438936 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -368,6 +368,7 @@ struct rtld_global_ro _rtld_global_ro attribute_relro = ._dl_lookup_symbol_x = _dl_lookup_symbol_x, ._dl_open = _dl_open, ._dl_close = _dl_close, + ._dl_catch_error = _rtld_catch_error, ._dl_tls_get_addr_soft = _dl_tls_get_addr_soft, #ifdef HAVE_DL_DISCOVER_OSVERSION ._dl_discover_osversion = _dl_discover_osversion diff --git a/elf/tst-dlmopen-dlerror-mod.c b/elf/tst-dlmopen-dlerror-mod.c new file mode 100644 index 0000000000..dcb94320b4 --- /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) 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 + +/* 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..65638f7f38 --- /dev/null +++ b/elf/tst-dlmopen-dlerror.c @@ -0,0 +1,37 @@ +/* Check that dlfcn errors are reported properly after dlmopen. + 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 + +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 ea3f7a69d0..b207f229c3 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -662,6 +662,12 @@ struct rtld_global_ro void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid, int argc, char *argv[], char *env[]); void (*_dl_close) (void *map); + /* 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. */ + int (*_dl_catch_error) (const char **objname, const char **errstring, + bool *mallocedp, void (*operate) (void *), + void *args); void *(*_dl_tls_get_addr_soft) (struct link_map *); #ifdef HAVE_DL_DISCOVER_OSVERSION int (*_dl_discover_osversion) (void); @@ -900,6 +906,9 @@ extern int _dl_catch_error (const char **objname, const char **errstring, void *args); libc_hidden_proto (_dl_catch_error) +/* Used for initializing GLRO (_dl_catch_error). */ +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