From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756931AbbFQXaI (ORCPT ); Wed, 17 Jun 2015 19:30:08 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:34931 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932713AbbFQWZp (ORCPT ); Wed, 17 Jun 2015 18:25:45 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Darrick J. Wong" , "Theodore Ts'o" , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 066/146] jbd2: fix r_count overflows leading to buffer overflow in journal recovery Date: Wed, 17 Jun 2015 15:22:51 -0700 Message-Id: <1434579851-1719-67-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1434579851-1719-1-git-send-email-kamal@canonical.com> References: <1434579851-1719-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt2 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Darrick J. Wong" commit e531d0bceb402e643a4499de40dd3fa39d8d2e43 upstream. The journal revoke block recovery code does not check r_count for sanity, which means that an evil value of r_count could result in the kernel reading off the end of the revoke table and into whatever garbage lies beyond. This could crash the kernel, so fix that. However, in testing this fix, I discovered that the code to write out the revoke tables also was not correctly checking to see if the block was full -- the current offset check is fine so long as the revoke table space size is a multiple of the record size, but this is not true when either journal_csum_v[23] are set. Signed-off-by: Darrick J. Wong Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara Signed-off-by: Kamal Mostafa --- fs/jbd2/recovery.c | 10 +++++++++- fs/jbd2/revoke.c | 18 ++++++++++-------- 2 files changed, 19 insertions(+), 9 deletions(-) diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c index bcbef08..a5f72a3 100644 --- a/fs/jbd2/recovery.c +++ b/fs/jbd2/recovery.c @@ -839,15 +839,23 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, { jbd2_journal_revoke_header_t *header; int offset, max; + int csum_size = 0; + __u32 rcount; int record_len = 4; header = (jbd2_journal_revoke_header_t *) bh->b_data; offset = sizeof(jbd2_journal_revoke_header_t); - max = be32_to_cpu(header->r_count); + rcount = be32_to_cpu(header->r_count); if (!jbd2_revoke_block_csum_verify(journal, header)) return -EINVAL; + if (jbd2_journal_has_csum_v2or3(journal)) + csum_size = sizeof(struct jbd2_journal_revoke_tail); + if (rcount > journal->j_blocksize - csum_size) + return -EINVAL; + max = rcount; + if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) record_len = 8; diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c index c6cbaef..14214da 100644 --- a/fs/jbd2/revoke.c +++ b/fs/jbd2/revoke.c @@ -577,7 +577,7 @@ static void write_one_revoke_record(journal_t *journal, { int csum_size = 0; struct buffer_head *descriptor; - int offset; + int sz, offset; journal_header_t *header; /* If we are already aborting, this all becomes a noop. We @@ -594,9 +594,14 @@ static void write_one_revoke_record(journal_t *journal, if (jbd2_journal_has_csum_v2or3(journal)) csum_size = sizeof(struct jbd2_journal_revoke_tail); + if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) + sz = 8; + else + sz = 4; + /* Make sure we have a descriptor with space left for the record */ if (descriptor) { - if (offset >= journal->j_blocksize - csum_size) { + if (offset + sz > journal->j_blocksize - csum_size) { flush_descriptor(journal, descriptor, offset, write_op); descriptor = NULL; } @@ -619,16 +624,13 @@ static void write_one_revoke_record(journal_t *journal, *descriptorp = descriptor; } - if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) { + if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) * ((__be64 *)(&descriptor->b_data[offset])) = cpu_to_be64(record->blocknr); - offset += 8; - - } else { + else * ((__be32 *)(&descriptor->b_data[offset])) = cpu_to_be32(record->blocknr); - offset += 4; - } + offset += sz; *offsetp = offset; } -- 1.9.1