From patchwork Fri Apr 15 12:01:48 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 11751 Received: (qmail 96534 invoked by alias); 15 Apr 2016 12:02:04 -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 96472 invoked by uid 89); 15 Apr 2016 12:02:01 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.9 required=5.0 tests=BAYES_00, RP_MATCHES_RCVD, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=UD:resource.h, resource.h, resourceh, Hx-languages-length:6271 X-HELO: mx1.redhat.com Subject: Re: [PATCH] vfprintf: Fix memory with large width and precision [BZ #19931] To: Paul Eggert References: <570BC02D.2040901@redhat.com> <570BC840.6060807@cs.ucla.edu> <570F8B9B.6020402@redhat.com> <570FC27E.8090104@cs.ucla.edu> Cc: libc-alpha@sourceware.org From: Florian Weimer Message-ID: <5710D82C.4000201@redhat.com> Date: Fri, 15 Apr 2016 14:01:48 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <570FC27E.8090104@cs.ucla.edu> On 04/14/2016 06:17 PM, Paul Eggert wrote: > On 04/14/2016 05:22 AM, Florian Weimer wrote: >> + /* Deallocate any previously allocated buffer because it is >> + too small. */ >> + if (__glibc_unlikely (workstart != NULL)) >> + free (workstart); >> if (__glibc_unlikely (prec >= INT_MAX / sizeof (CHAR_T) - 32)) > > Why don't we need a 'workstart = NULL' after freeing workstart, which is > the pattern used elsewhere? If it's not needed here, it'd be helpful to > have a comment saying why not. Ugh, right. I swear it was there at some point. I've enhanced the test to catch this. Florian 2016-04-15 Florian Weimer [BZ #19931] * stdio-common/tst-vfprintf-width-prec.c: New file. * stdio-common/Makefile (tests): Add tst-vfprintf-width-prec. (tests-special): Add tst-vfprintf-width-prec-mem.out. (generated): Add mtrace-related files. (tst-vfprintf-width-prec-ENV): Set MALLOC_TRACE. (tst-%-mem.out): New pattern rule, replaces tst-printf-bz18872-mem.out. * stdio-common/vfprintf.c (vfprintf): When handling a precision specifier, deallocate any previously allocated work buffer. diff --git a/stdio-common/Makefile b/stdio-common/Makefile index cc79d34..6c597c1 100644 --- a/stdio-common/Makefile +++ b/stdio-common/Makefile @@ -58,16 +58,18 @@ tests := tstscanf test_rdwr test-popen tstgetln test-fseek \ scanf16 scanf17 tst-setvbuf1 tst-grouping bug23 bug24 \ bug-vfprintf-nargs tst-long-dbl-fphex tst-fphex-wide tst-sprintf3 \ bug25 tst-printf-round bug23-2 bug23-3 bug23-4 bug26 tst-fmemopen3 \ - tst-printf-bz18872 + tst-printf-bz18872 tst-vfprintf-width-prec test-srcs = tst-unbputc tst-printf ifeq ($(run-built-tests),yes) tests-special += $(objpfx)tst-unbputc.out $(objpfx)tst-printf.out \ $(objpfx)tst-printf-bz18872-mem.out \ - $(objpfx)tst-setvbuf1-cmp.out + $(objpfx)tst-setvbuf1-cmp.out \ + $(objpfx)tst-vfprintf-width-prec-mem.out generated += tst-printf-bz18872.c tst-printf-bz18872.mtrace \ - tst-printf-bz18872-mem.out + tst-printf-bz18872-mem.out \ + tst-vfprintf-width-prec.mtrace tst-vfprintf-width-prec-mem.out endif include ../Rules @@ -86,6 +88,8 @@ $(objpfx)tst-swprintf.out: $(gen-locales) endif tst-printf-bz18872-ENV = MALLOC_TRACE=$(objpfx)tst-printf-bz18872.mtrace +tst-vfprintf-width-prec-ENV = \ + MALLOC_TRACE=$(objpfx)tst-vfprintf-width-prec.mtrace $(objpfx)tst-unbputc.out: tst-unbputc.sh $(objpfx)tst-unbputc $(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \ @@ -100,8 +104,8 @@ $(objpfx)tst-printf.out: tst-printf.sh $(objpfx)tst-printf $(objpfx)tst-printf-bz18872.c: tst-printf-bz18872.sh rm -f $@ && $(BASH) $^ > $@.new && mv $@.new $@ -$(objpfx)tst-printf-bz18872-mem.out: $(objpfx)tst-printf-bz18872.out - $(common-objpfx)malloc/mtrace $(objpfx)tst-printf-bz18872.mtrace > $@; \ +$(objpfx)tst-%-mem.out: $(objpfx)tst-%.out + $(common-objpfx)malloc/mtrace $(objpfx)tst-$*.mtrace > $@; \ $(evaluate-test) CFLAGS-vfprintf.c = -Wno-uninitialized diff --git a/stdio-common/tst-vfprintf-width-prec.c b/stdio-common/tst-vfprintf-width-prec.c new file mode 100644 index 0000000..2892741 --- /dev/null +++ b/stdio-common/tst-vfprintf-width-prec.c @@ -0,0 +1,107 @@ +/* Test for memory leak with large width and precision. + Copyright (C) 1991-2016 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 + +static int +do_test (void) +{ + mtrace (); + + int ret; + { + char *result; + ret = asprintf (&result, "%133000.133001x", 17); + if (ret < 0) + { + printf ("error: asprintf: %m\n"); + return 1; + } + free (result); + } + { + wchar_t *result = calloc (ret + 1, sizeof (wchar_t)); + if (result == NULL) + { + printf ("error: calloc (%d, %zu): %m", ret + 1, sizeof (wchar_t)); + return 1; + } + + ret = swprintf (result, ret + 1, L"%133000.133001x", 17); + if (ret < 0) + { + printf ("error: swprintf: %d (%m)\n", ret); + return 1; + } + free (result); + } + + /* Limit the size of the process, so that the second allocation will + fail. */ + { + struct rlimit limit; + if (getrlimit (RLIMIT_AS, &limit) != 0) + { + printf ("getrlimit (RLIMIT_AS) failed: %m\n"); + return 1; + } + long target = 200 * 1024 * 1024; + if (limit.rlim_cur == RLIM_INFINITY || limit.rlim_cur > target) + { + limit.rlim_cur = target; + if (setrlimit (RLIMIT_AS, &limit) != 0) + { + printf ("setrlimit (RLIMIT_AS) failed: %m\n"); + return 1; + } + } + } + + { + char *result; + ret = asprintf (&result, "%133000.999999999x", 17); + if (ret >= 0) + { + printf ("error: asprintf: incorrect result %d\n", ret); + return 1; + } + } + { + wchar_t result[100]; + if (result == NULL) + { + printf ("error: calloc (%d, %zu): %m", ret + 1, sizeof (wchar_t)); + return 1; + } + + ret = swprintf (result, 100, L"%133000.999999999x", 17); + if (ret >= 0) + { + printf ("error: swprintf: incorrect result %d\n", ret); + return 1; + } + } + + return 0; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" diff --git a/stdio-common/vfprintf.c b/stdio-common/vfprintf.c index 6829d4d..f24020a 100644 --- a/stdio-common/vfprintf.c +++ b/stdio-common/vfprintf.c @@ -1564,6 +1564,11 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap) prec = 0; if (prec > width && prec > WORK_BUFFER_SIZE - 32) { + /* Deallocate any previously allocated buffer because it is + too small. */ + if (__glibc_unlikely (workstart != NULL)) + free (workstart); + workstart = NULL; if (__glibc_unlikely (prec >= INT_MAX / sizeof (CHAR_T) - 32)) { __set_errno (EOVERFLOW);