From 331be56598b284d41370c67046df25673b040a55 Mon Sep 17 00:00:00 2001 From: Sergey Poznyakoff Date: Thu, 27 Dec 2018 17:48:57 +0200 Subject: [PATCH] Fix CVE-2018-20482 * NEWS: Update. * src/sparse.c (sparse_dump_region): Handle short read condition. (sparse_extract_region,check_data_region): Fix dumped_size calculation. Handle short read condition. (pax_decode_header): Fix dumped_size calculation. * tests/Makefile.am: Add new testcases. * tests/testsuite.at: Likewise. * tests/sptrcreat.at: New file. * tests/sptrdiff00.at: New file. * tests/sptrdiff01.at: New file. CVE: CVE-2018-20482 Upstream-Status: Backport [http://git.savannah.gnu.org/cgit/tar.git/commit/?id=c15c42ccd1e2377945fd0414eca1a49294bff454] Signed-off-by: Dan Tran --- src/sparse.c | 50 +++++++++++++++++++++++++++++++----- tests/Makefile.am | 5 +++- tests/sptrcreat.at | 62 +++++++++++++++++++++++++++++++++++++++++++++ tests/sptrdiff00.at | 55 ++++++++++++++++++++++++++++++++++++++++ tests/sptrdiff01.at | 55 ++++++++++++++++++++++++++++++++++++++++ tests/testsuite.at | 5 +++- 6 files changed, 224 insertions(+), 8 deletions(-) create mode 100644 tests/sptrcreat.at create mode 100644 tests/sptrdiff00.at create mode 100644 tests/sptrdiff01.at diff --git a/src/sparse.c b/src/sparse.c index 0830f62..e8e8259 100644 --- a/src/sparse.c +++ b/src/sparse.c @@ -1,6 +1,6 @@ /* Functions for dealing with sparse files - Copyright 2003-2007, 2010, 2013-2017 Free Software Foundation, Inc. + Copyright 2003-2007, 2010, 2013-2018 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the @@ -427,6 +427,30 @@ sparse_dump_region (struct tar_sparse_file *file, size_t i) bufsize); return false; } + else if (bytes_read == 0) + { + char buf[UINTMAX_STRSIZE_BOUND]; + struct stat st; + size_t n; + if (fstat (file->fd, &st) == 0) + n = file->stat_info->stat.st_size - st.st_size; + else + n = file->stat_info->stat.st_size + - (file->stat_info->sparse_map[i].offset + + file->stat_info->sparse_map[i].numbytes + - bytes_left); + + WARNOPT (WARN_FILE_SHRANK, + (0, 0, + ngettext ("%s: File shrank by %s byte; padding with zeros", + "%s: File shrank by %s bytes; padding with zeros", + n), + quotearg_colon (file->stat_info->orig_file_name), + STRINGIFY_BIGINT (n, buf))); + if (! ignore_failed_read_option) + set_exit_status (TAREXIT_DIFFERS); + return false; + } memset (blk->buffer + bytes_read, 0, BLOCKSIZE - bytes_read); bytes_left -= bytes_read; @@ -464,9 +488,9 @@ sparse_extract_region (struct tar_sparse_file *file, size_t i) return false; } set_next_block_after (blk); + file->dumped_size += BLOCKSIZE; count = blocking_write (file->fd, blk->buffer, wrbytes); write_size -= count; - file->dumped_size += count; mv_size_left (file->stat_info->archive_file_size - file->dumped_size); file->offset += count; if (count != wrbytes) @@ -598,6 +622,12 @@ check_sparse_region (struct tar_sparse_file *file, off_t beg, off_t end) rdsize); return false; } + else if (bytes_read == 0) + { + report_difference (file->stat_info, _("Size differs")); + return false; + } + if (!zero_block_p (diff_buffer, bytes_read)) { char begbuf[INT_BUFSIZE_BOUND (off_t)]; @@ -609,6 +639,7 @@ check_sparse_region (struct tar_sparse_file *file, off_t beg, off_t end) beg += bytes_read; } + return true; } @@ -635,6 +666,7 @@ check_data_region (struct tar_sparse_file *file, size_t i) return false; } set_next_block_after (blk); + file->dumped_size += BLOCKSIZE; bytes_read = safe_read (file->fd, diff_buffer, rdsize); if (bytes_read == SAFE_READ_ERROR) { @@ -645,7 +677,11 @@ check_data_region (struct tar_sparse_file *file, size_t i) rdsize); return false; } - file->dumped_size += bytes_read; + else if (bytes_read == 0) + { + report_difference (¤t_stat_info, _("Size differs")); + return false; + } size_left -= bytes_read; mv_size_left (file->stat_info->archive_file_size - file->dumped_size); if (memcmp (blk->buffer, diff_buffer, rdsize)) @@ -1213,7 +1249,8 @@ pax_decode_header (struct tar_sparse_file *file) union block *blk; char *p; size_t i; - + off_t start; + #define COPY_BUF(b,buf,src) do \ { \ char *endp = b->buffer + BLOCKSIZE; \ @@ -1229,7 +1266,6 @@ pax_decode_header (struct tar_sparse_file *file) if (src == endp) \ { \ set_next_block_after (b); \ - file->dumped_size += BLOCKSIZE; \ b = find_next_block (); \ if (!b) \ FATAL_ERROR ((0, 0, _("Unexpected EOF in archive"))); \ @@ -1242,8 +1278,8 @@ pax_decode_header (struct tar_sparse_file *file) dst[-1] = 0; \ } while (0) + start = current_block_ordinal (); set_next_block_after (current_header); - file->dumped_size += BLOCKSIZE; blk = find_next_block (); if (!blk) FATAL_ERROR ((0, 0, _("Unexpected EOF in archive"))); @@ -1282,6 +1318,8 @@ pax_decode_header (struct tar_sparse_file *file) sparse_add_map (file->stat_info, &sp); } set_next_block_after (blk); + + file->dumped_size += BLOCKSIZE * (current_block_ordinal () - start); } return true; diff --git a/tests/Makefile.am b/tests/Makefile.am index 2d7939d..ac3b6e7 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -1,6 +1,6 @@ # Makefile for GNU tar regression tests. -# Copyright 1996-1997, 1999-2001, 2003-2007, 2009, 2012-2015 Free Software +# Copyright 1996-1997, 1999-2001, 2003-2007, 2009, 2012-2018 Free Software # This file is part of GNU tar. @@ -228,6 +228,9 @@ TESTSUITE_AT = \ spmvp00.at\ spmvp01.at\ spmvp10.at\ + sptrcreat.at\ + sptrdiff00.at\ + sptrdiff01.at\ time01.at\ time02.at\ truncate.at\ diff --git a/tests/sptrcreat.at b/tests/sptrcreat.at new file mode 100644 index 0000000..8e28f0e --- /dev/null +++ b/tests/sptrcreat.at @@ -0,0 +1,62 @@ +# Process this file with autom4te to create testsuite. -*- Autotest -*- + +# Test suite for GNU tar. +# Copyright 2018 Free Software Foundation, Inc. + +# This file is part of GNU tar. + +# GNU tar is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. + +# GNU tar 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 General Public License for more details. + +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# Tar up to 1.30 would loop endlessly if a sparse file had been truncated +# while being archived (with --sparse flag). +# +# The bug has been assigned id CVE-2018-20482 (on the grounds that it is a +# denial of service possibility). +# +# Reported by: Chris Siebenmann +# References: <20181226223948.781EB32008E@apps1.cs.toronto.edu>, +# +# +# + +AT_SETUP([sparse file truncated while archiving]) +AT_KEYWORDS([truncate filechange sparse sptr sptrcreat]) + +AT_TAR_CHECK([ +genfile --sparse --block-size=1024 --file foo \ + 0 ABCDEFGHIJ 1M ABCDEFGHIJ 10M ABCDEFGHIJ 200M ABCDEFGHIJ +genfile --file baz +genfile --run --checkpoint 3 --length 200m --truncate foo -- \ + tar --checkpoint=1 \ + --checkpoint-action=echo \ + --checkpoint-action=sleep=1 \ + --sparse -vcf bar foo baz +echo Exit status: $? +echo separator +genfile --file foo --seek 200m --length 11575296 --pattern=zeros +tar dvf bar], +[1], +[foo +baz +Exit status: 1 +separator +foo +foo: Mod time differs +baz +], +[tar: foo: File shrank by 11575296 bytes; padding with zeros +], +[],[],[posix, gnu, oldgnu]) + +AT_CLEANUP diff --git a/tests/sptrdiff00.at b/tests/sptrdiff00.at new file mode 100644 index 0000000..c410561 --- /dev/null +++ b/tests/sptrdiff00.at @@ -0,0 +1,55 @@ +# Process this file with autom4te to create testsuite. -*- Autotest -*- +# +# Test suite for GNU tar. +# Copyright 2018 Free Software Foundation, Inc. +# +# This file is part of GNU tar. +# +# GNU tar is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# GNU tar 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 General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# While fixing CVE-2018-20482 (see sptrcreat.at) it has been discovered +# that similar bug exists in file checking code (tar d). +# This test case checks if tar correctly handles a short read condition +# appearing in check_sparse_region. + +AT_SETUP([file truncated in sparse region while comparing]) +AT_KEYWORDS([truncate filechange sparse sptr sptrdiff diff]) + +# This triggers short read in check_sparse_region. +AT_TAR_CHECK([ +genfile --sparse --block-size=1024 --file foo \ + 0 ABCDEFGHIJ 1M ABCDEFGHIJ 10M ABCDEFGHIJ 200M ABCDEFGHIJ +genfile --file baz +echo creating +tar --sparse -vcf bar foo baz +echo comparing +genfile --run --checkpoint 3 --length 200m --truncate foo -- \ + tar --checkpoint=1 \ + --checkpoint-action=echo='Write checkpoint %u' \ + --checkpoint-action=sleep=1 \ + --sparse -vdf bar +], +[1], +[creating +foo +baz +comparing +foo +foo: Size differs +baz +], +[], +[],[],[posix, gnu, oldgnu]) + +AT_CLEANUP diff --git a/tests/sptrdiff01.at b/tests/sptrdiff01.at new file mode 100644 index 0000000..2da2267 --- /dev/null +++ b/tests/sptrdiff01.at @@ -0,0 +1,55 @@ +# Process this file with autom4te to create testsuite. -*- Autotest -*- +# +# Test suite for GNU tar. +# Copyright 2018 Free Software Foundation, Inc. +# +# This file is part of GNU tar. +# +# GNU tar is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# GNU tar 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 General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# While fixing CVE-2018-20482 (see sptrcreat.at) it has been discovered +# that similar bug exists in file checking code (tar d). +# This test case checks if tar correctly handles a short read condition +# appearing in check_data_region. + +AT_SETUP([file truncated in data region while comparing]) +AT_KEYWORDS([truncate filechange sparse sptr sptrdiff diff]) + +# This triggers short read in check_data_region. +AT_TAR_CHECK([ +genfile --sparse --block-size=1024 --file foo \ + 0 ABCDEFGHIJ 1M ABCDEFGHIJ 10M ABCDEFGHIJ 200M ABCDEFGHIJ +genfile --file baz +echo creating +tar --sparse -vcf bar foo baz +echo comparing +genfile --run --checkpoint 5 --length 221278210 --truncate foo -- \ + tar --checkpoint=1 \ + --checkpoint-action=echo='Write checkpoint %u' \ + --checkpoint-action=sleep=1 \ + --sparse -vdf bar +], +[1], +[creating +foo +baz +comparing +foo +foo: Size differs +baz +], +[], +[],[],[posix, gnu, oldgnu]) + +AT_CLEANUP diff --git a/tests/testsuite.at b/tests/testsuite.at index 2a83757..23386f7 100644 --- a/tests/testsuite.at +++ b/tests/testsuite.at @@ -1,7 +1,7 @@ # Process this file with autom4te to create testsuite. -*- Autotest -*- # Test suite for GNU tar. -# Copyright 2004-2008, 2010-2017 Free Software Foundation, Inc. +# Copyright 2004-2008, 2010-2018 Free Software Foundation, Inc. # This file is part of GNU tar. @@ -405,6 +405,9 @@ m4_include([sparsemv.at]) m4_include([spmvp00.at]) m4_include([spmvp01.at]) m4_include([spmvp10.at]) +m4_include([sptrcreat.at]) +m4_include([sptrdiff00.at]) +m4_include([sptrdiff01.at]) AT_BANNER([Updates]) m4_include([update.at]) -- 2.22.0.vfs.1.1.57.gbaf16c8