From patchwork Wed Nov 29 13:39:53 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 24596 Received: (qmail 103795 invoked by alias); 29 Nov 2017 13:40:09 -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 103725 invoked by uid 89); 29 Nov 2017 13:40:07 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-25.5 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, KB_WAM_FROM_NAME_SINGLEWORD, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.2 spammy=backup, ly, lx, Lx X-HELO: mail-qt0-f176.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id; bh=XZ56SwJvuuqMNYVToUAymXO2VG9MGUbEwJ5Qq5Ur/qY=; b=Rc0WfFWaYP1I4QLJ2P9i5CPxeFGPhmJDfNu2DLBFKp28a+N65pkXQVCLZ54nmulg/u JCQwt6SHnbP3TkkYPrMwPKqR2EgY9GQqT2iAYK0Xe64jXETXI7QSFERwmcsZxTZ/iwVT M7RR30/h9VKWWEnLOj37QgFZ/aFuiqnEknjcYIvOeKLrN7Njokjqhz99jQsDQFcdNhu/ 6vnCWZBgRk7h5cKiUs+vEbwQVUh8tRh2dn1tQXwhE1epDmPksIONHtTg/bWPVNv/LZ0U Tm+6FsVR1N7duk2l0qJ6skuLhWW+Dz9LCzs9kOjJ+HyCmYAVs4O8oKcuXFTikDNYg4YS 8gQg== X-Gm-Message-State: AJaThX6q9LqiX2jJaHiBPcQI4Dpofxrvbd2l13NjvGWHYMPagSVrY1ml m4R8RPFO55U82eoTSULAr3Oq5FlwaIk= X-Google-Smtp-Source: AGs4zMbMeVLo/5uYQZOKwPdmaAbB3ZjgErH5jl1JBduEKj1pPkDbgtbPRPO1Y959rKqqX2Fw+TMRwg== X-Received: by 10.200.8.11 with SMTP id u11mr4613327qth.315.1511962801799; Wed, 29 Nov 2017 05:40:01 -0800 (PST) From: Adhemerval Zanella To: libc-alpha@sourceware.org Subject: [PATCH] libio: Free backup area when it not required (BZ#22415) Date: Wed, 29 Nov 2017 11:39:53 -0200 Message-Id: <1511962793-14533-1-git-send-email-adhemerval.zanella@linaro.org> Some libio operations fail to correctly free the backup area (created by _IO_{w}default_pbackfail on unget{w}c) resulting in either invalid buffer free operations or memory leaks. For instance, on the example provided by BZ#22415 a following fputc after a fseek to rewind the stream issues an invalid free on the buffer. It is because although _IO_file_overflow correctly (from fputc) correctly calls _IO_free_backup_area, the _IO_new_file_seekoff (called by fseek) updates the FILE internal pointers without first free the backup area (resulting in invalid values in the internal pointers). The wide version also shows an issue, but instead of accessing invalid pointers it leaks the backup memory on fseek/fputwc operation. Checked on x86_64-linux-gnu and i686-linux-gnu. * libio/Makefile (tests): Add tst-bz22415. (tst-bz22415-ENV): New rule. (generated): Add tst-bz22415.mtrace and tst-bz22415.check. (tests-special): Add tst-bz22415-mem.out. ($(objpfx)tst-bz22415-mem.out): New rule. * libio/fileops.c (_IO_new_file_seekoff): Call _IO_free_backup_area in case of a successful seek operation. * libio/wfileops.c (_IO_wfile_seekoff): Likewise. (_IO_wfile_overflow): Call _IO_free_wbackup_area in case a write buffer is required. * libio/tst-bz22415.c: New test. --- ChangeLog | 14 ++++++++ libio/Makefile | 11 ++++-- libio/fileops.c | 3 ++ libio/tst-bz22415.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++ libio/wfileops.c | 4 +++ 5 files changed, 127 insertions(+), 2 deletions(-) create mode 100644 libio/tst-bz22415.c diff --git a/libio/Makefile b/libio/Makefile index 9d09bd8..70b5530 100644 --- a/libio/Makefile +++ b/libio/Makefile @@ -62,7 +62,7 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc \ bug-memstream1 bug-wmemstream1 \ tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos tst-fseek \ tst-fwrite-error tst-ftell-partial-wide tst-ftell-active-handler \ - tst-ftell-append tst-fputws + tst-ftell-append tst-fputws tst-bz22415 ifeq (yes,$(build-shared)) # Add test-fopenloc only if shared library is enabled since it depends on # shared localedata objects. @@ -151,9 +151,11 @@ tst_wprintf2-ARGS = "Some Text" test-fmemopen-ENV = MALLOC_TRACE=$(objpfx)test-fmemopen.mtrace tst-fopenloc-ENV = MALLOC_TRACE=$(objpfx)tst-fopenloc.mtrace +tst-bz22415-ENV = MALLOC_TRACE=$(objpfx)tst-bz22415.mtrace generated += test-fmemopen.mtrace test-fmemopen.check generated += tst-fopenloc.mtrace tst-fopenloc.check +generated += tst-bz22415.mtrace tst-bz22415.check aux := fileops genops stdfiles stdio strops @@ -167,7 +169,8 @@ shared-only-routines = oldiofopen oldiofdopen oldiofclose oldfileops \ oldiofsetpos64 ifeq ($(run-built-tests),yes) -tests-special += $(objpfx)test-freopen.out $(objpfx)test-fmemopen-mem.out +tests-special += $(objpfx)test-freopen.out $(objpfx)test-fmemopen-mem.out \ + $(objpfx)tst-bz22415-mem.out ifeq (yes,$(build-shared)) # Run tst-fopenloc-cmp.out and tst-openloc-mem.out only if shared # library is enabled since they depend on tst-fopenloc.out. @@ -218,3 +221,7 @@ $(objpfx)test-fmemopen-mem.out: $(objpfx)test-fmemopen.out $(objpfx)tst-fopenloc-mem.out: $(objpfx)tst-fopenloc.out $(common-objpfx)malloc/mtrace $(objpfx)tst-fopenloc.mtrace > $@; \ $(evaluate-test) + +$(objpfx)tst-bz22415-mem.out: $(objpfx)tst-bz22415.out + $(common-objpfx)malloc/mtrace $(objpfx)tst-bz22415.mtrace > $@; \ + $(evaluate-test) diff --git a/libio/fileops.c b/libio/fileops.c index a9e948f..72a0cb5 100644 --- a/libio/fileops.c +++ b/libio/fileops.c @@ -994,6 +994,9 @@ _IO_new_file_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode) goto dumb; } } + + _IO_free_backup_area (fp); + /* At this point, dir==_IO_seek_set. */ /* If destination is within current buffer, optimize: */ diff --git a/libio/tst-bz22415.c b/libio/tst-bz22415.c new file mode 100644 index 0000000..d7b23fe --- /dev/null +++ b/libio/tst-bz22415.c @@ -0,0 +1,97 @@ +/* Check static buffer handling with setvbuf (BZ #22415) + + Copyright (C) 2017 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 + +static int +do_test (void) +{ + mtrace (); + + char *temp_file; + TEST_VERIFY_EXIT (create_temp_file ("tst-bz22145.", &temp_file)); + + char buf[BUFSIZ]; + + { + /* Check if backup buffer is correctly freed and changing back + to normal buffer does not trigger an invalid free in case of + static buffer set by setvbuf. */ + + FILE *f = fopen (temp_file, "w+b"); + TEST_VERIFY_EXIT (f != NULL); + + TEST_VERIFY_EXIT (setvbuf (f, buf, _IOFBF, BUFSIZ) == 0); + TEST_VERIFY_EXIT (ungetc ('x', f) == 'x'); + TEST_VERIFY_EXIT (fseek (f, 0L, SEEK_SET) == 0); + TEST_VERIFY_EXIT (fputc ('y', f) == 'y'); + + TEST_VERIFY_EXIT (fclose (f) == 0); + } + + { + /* Check if backup buffer is correctly freed and changing back + to normal buffer does not trigger an invalid free in case of + static buffer set by setvbuf. */ + + FILE *f = fopen (temp_file, "w+b"); + TEST_VERIFY_EXIT (f != NULL); + + TEST_VERIFY_EXIT (setvbuf (f, buf, _IOFBF, BUFSIZ) == 0); + TEST_VERIFY_EXIT (ungetc ('x', f) == 'x'); + TEST_VERIFY_EXIT (fputc ('y', f) == 'y'); + + TEST_VERIFY_EXIT (fclose (f) == 0); + } + + { + FILE *f = fopen (temp_file, "w+b"); + TEST_VERIFY_EXIT (f != NULL); + + TEST_VERIFY_EXIT (setvbuf (f, buf, _IOFBF, BUFSIZ) == 0); + TEST_VERIFY_EXIT (ungetwc (L'x', f) == L'x'); + TEST_VERIFY_EXIT (fseek (f, 0L, SEEK_SET) == 0); + TEST_VERIFY_EXIT (fputwc (L'y', f) == L'y'); + + TEST_VERIFY_EXIT (fclose (f) == 0); + } + + { + FILE *f = fopen (temp_file, "w+b"); + TEST_VERIFY_EXIT (f != NULL); + + TEST_VERIFY_EXIT (setvbuf (f, buf, _IOFBF, BUFSIZ) == 0); + TEST_VERIFY_EXIT (ungetwc (L'x', f) == L'x'); + TEST_VERIFY_EXIT (fputwc (L'y', f) == L'y'); + + TEST_VERIFY_EXIT (fclose (f) == 0); + } + + free (temp_file); + + return 0; +} + +#include diff --git a/libio/wfileops.c b/libio/wfileops.c index 8756b6f..91139e1 100644 --- a/libio/wfileops.c +++ b/libio/wfileops.c @@ -421,6 +421,7 @@ _IO_wfile_overflow (_IO_FILE *f, wint_t wch) if (f->_wide_data->_IO_write_base == 0) { _IO_wdoallocbuf (f); + _IO_free_wbackup_area (f); _IO_wsetg (f, f->_wide_data->_IO_buf_base, f->_wide_data->_IO_buf_base, f->_wide_data->_IO_buf_base); @@ -850,6 +851,9 @@ _IO_wfile_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode) goto dumb; } } + + _IO_free_wbackup_area (fp); + /* At this point, dir==_IO_seek_set. */ /* If destination is within current buffer, optimize: */