From patchwork Thu Nov 29 16:20:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Pluzhnikov X-Patchwork-Id: 30391 Received: (qmail 130235 invoked by alias); 29 Nov 2018 16:21:17 -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 130225 invoked by uid 89); 29 Nov 2018 16:21:16 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-34.9 required=5.0 tests=BAYES_00, ENV_AND_HDR_SPF_MATCH, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_PASS, USER_IN_DEF_SPF_WL autolearn=ham version=3.3.2 spammy= X-HELO: mail-yb1-f179.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Gwgl9VmP2L/08phCib1RKmubDPLxj0mhIhTiLCs7Dgw=; b=mameEw6sv4R2YLv/9anV7+xyuLhMPQLh7mwjQLcQloirIRo2LUV87RgpKN4JZHt0ZM jLUyBr6S3dJwaQ7My8y7lWgrCQaI+lPc7Avg6XPw33tRs6gU9JxUOS7wNnYigs81qwXn J1DsjjxmBgzYQp9gcRUKOnPJg6Ay3AVEKdbuvMi32sM5UwCROdafMbDoSil+PckjPsK2 MNsadHQegMTsVaSG+fADt2ytMTcQUHpUlsj4Ajgy40372hOA2U+TjWcoHXKcRpr5lA66 iwWhOXkBnTJ8yuurZJVMvEKGvI6kzhWiMumc/t5Vn93EEsIGru3O0eg8wUyHfsUm6Kex fc9A== MIME-Version: 1.0 References: <03b9e2fe-0851-77b2-2ad4-d99aeaa362a2@redhat.com> <20181113115906.0d5e5b22@tereshkova.br.ibm.com> <87h8gja680.fsf@oldenburg.str.redhat.com> <87k1kxaunf.fsf@oldenburg.str.redhat.com> <87zhtt9cyf.fsf@oldenburg.str.redhat.com> <877egv3ov8.fsf@oldenburg.str.redhat.com> In-Reply-To: <877egv3ov8.fsf@oldenburg.str.redhat.com> From: Paul Pluzhnikov Date: Thu, 29 Nov 2018 08:20:42 -0800 Message-ID: Subject: Re: [patch] Fix BZ#20544 (assert function passed to atexit/on_exit/__cxa_atexit != NULL) To: Florian Weimer Cc: Adhemerval Zanella , GLIBC Devel On Thu, Nov 29, 2018 at 7:06 AM Florian Weimer wrote: > Perhaps: > > stdlib: assert on NULL function pointer in atexit etc. [BZ #20544] Thanks. Revised patch attached. diff --git a/ChangeLog b/ChangeLog index 488774e236..b27cc6f0a4 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2018-11-29 Paul Pluzhnikov + + [BZ #20544] + * stdlib/cxa_atexit.c (__internal_atexit): assert func != NULL. + * stdlib/on_exit.c (__on_exit): Likewise. + * stdlib/Makefile (tests): Add tst-bz20544. + * stdlib/tst-bz20544.c: New test. + 2018-11-29 Florian Weimer * posix/Makefile (before-compile): Remove testcases.h and diff --git a/stdlib/Makefile b/stdlib/Makefile index 98dbddc43c..8bce89fffe 100644 --- a/stdlib/Makefile +++ b/stdlib/Makefile @@ -87,7 +87,7 @@ tests := tst-strtol tst-strtod testmb testrand testsort testdiv \ tst-makecontext-align test-bz22786 tst-strtod-nan-sign \ tst-swapcontext1 tst-setcontext4 tst-setcontext5 \ tst-setcontext6 tst-setcontext7 tst-setcontext8 \ - tst-setcontext9 + tst-setcontext9 tst-bz20544 tests-internal := tst-strtod1i tst-strtod3 tst-strtod4 tst-strtod5i \ tst-tls-atexit tst-tls-atexit-nodelete diff --git a/stdlib/cxa_atexit.c b/stdlib/cxa_atexit.c index 6d65f7e615..37b22d5801 100644 --- a/stdlib/cxa_atexit.c +++ b/stdlib/cxa_atexit.c @@ -36,6 +36,10 @@ __internal_atexit (void (*func) (void *), void *arg, void *d, { struct exit_function *new; + /* As a QoI issue we detect NULL early with an assertion instead + of a SIGSEGV at program exit when the handler is run (bug 20544). */ + assert (func != NULL); + __libc_lock_lock (__exit_funcs_lock); new = __new_exitfn (listp); diff --git a/stdlib/on_exit.c b/stdlib/on_exit.c index 5241e0d86f..1dff7ff631 100644 --- a/stdlib/on_exit.c +++ b/stdlib/on_exit.c @@ -15,6 +15,7 @@ License along with the GNU C Library; if not, see . */ +#include #include #include "exit.h" #include @@ -25,6 +26,10 @@ __on_exit (void (*func) (int status, void *arg), void *arg) { struct exit_function *new; + /* As a QoI issue we detect NULL early with an assertion instead + of a SIGSEGV at program exit when the handler is run (bug 20544). */ + assert (func != NULL); + __libc_lock_lock (__exit_funcs_lock); new = __new_exitfn (&__exit_funcs); diff --git a/stdlib/tst-bz20544.c b/stdlib/tst-bz20544.c new file mode 100644 index 0000000000..33b87cc77e --- /dev/null +++ b/stdlib/tst-bz20544.c @@ -0,0 +1,115 @@ +/* Verify atexit, on_exit, etc. abort on NULL function pointer. + Copyright (C) 2018 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 +#include +#include +#include + +extern int __cxa_atexit (void (*func) (void *), void *arg, void *d); +extern int __cxa_at_quick_exit (void (*func) (void *), void *arg, void *d); + +/* GCC "knows" that atexit and on_exit should not be called with NULL + function pointer, and emits diagnostics if we try to do so. + Presumably it could emit a trap and drop the call altogether. + + The aliases below are intended to bypass this. */ + +extern int atexit_alias (void (*) (void)) __asm__ ("atexit"); +extern int at_quick_exit_alias (void (*) (void)) __asm__ ("at_quick_exit"); +extern int on_exit_alias (void (*) (void), void *) __asm__ ("on_exit"); + + +static void +test_bz20544_atexit (void *closure) +{ + atexit_alias (NULL); /* Should assert. */ + exit (EXIT_FAILURE); +} + +static void +test_bz20544_at_quick_exit (void *closure) +{ + at_quick_exit_alias (NULL); /* Should assert. */ + exit (EXIT_FAILURE); +} + +static void +test_bz20544_on_exit (void *closure) +{ + on_exit_alias (NULL, NULL); /* Should assert. */ + exit (EXIT_FAILURE); +} + +static void +test_bz20544_cxa_atexit (void *closure) +{ + __cxa_atexit (NULL, NULL, NULL); /* Should assert. */ + exit (EXIT_FAILURE); +} + +static void +test_bz20544_cxa_at_quick_exit (void *closure) +{ + __cxa_at_quick_exit (NULL, NULL, NULL); /* Should assert. */ + exit (EXIT_FAILURE); +} + +static void +test_one_fn (void (*test_fn) (void *)) +{ + const char expected_error[] = "Assertion `func != NULL' failed.\n"; + struct support_capture_subprocess result; + result = support_capture_subprocess (test_fn, NULL); + support_capture_subprocess_check (&result, "bz20544", -SIGABRT, + sc_allow_stderr); + + if (strstr (result.err.buffer, expected_error) == NULL) + { + support_record_failure (); + printf ("Did not find expected string in error output:\n" + " expected: >>>%s<<<\n" + " actual: >>>%s<<<\n", + expected_error, result.err.buffer); + } + + support_capture_subprocess_free (&result); +} + +static int +do_test (void) +{ +#if defined (NDEBUG) + FAIL_UNSUPPORTED ("Assertions disabled (NDEBUG). " + "Can't verify that assertions fire."); +#endif + test_one_fn (test_bz20544_atexit); + test_one_fn (test_bz20544_at_quick_exit); + test_one_fn (test_bz20544_on_exit); + test_one_fn (test_bz20544_cxa_atexit); + test_one_fn (test_bz20544_cxa_at_quick_exit); + + return 0; +} + +#include