From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Darrick J. Wong" Subject: [PATCH 33/31] e2fsck: on read error, don't rewrite blocks past the end of the fs Date: Mon, 22 Dec 2014 10:55:04 -0800 Message-ID: <20141222185504.GH5368@birch.djwong.org> References: <20141220211640.25563.80596.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: tytso@mit.edu Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:45875 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754295AbaLVSzI (ORCPT ); Mon, 22 Dec 2014 13:55:08 -0500 Content-Disposition: inline In-Reply-To: <20141220211640.25563.80596.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: If e2fsck encounters a read error on a block past the end of the filesystem, don't bother trying to "rewrite" the block. We might still want to re-try the read to capture FS data marooned past the end of the filesystem, but in that case e2fsck ought to move the block back inside the filesystem. This enables e2fuzz to detect writes past the end of the FS due to software bugs. Signed-off-by: Darrick J. Wong --- e2fsck/ehandler.c | 5 +++++ misc/e2fuzz.sh | 7 +++++++ 2 files changed, 12 insertions(+) diff --git a/e2fsck/ehandler.c b/e2fsck/ehandler.c index 6dddf9c..71ca301 100644 --- a/e2fsck/ehandler.c +++ b/e2fsck/ehandler.c @@ -58,6 +58,11 @@ static errcode_t e2fsck_handle_read_error(io_channel channel, printf(_("Error reading block %lu (%s). "), block, error_message(error)); preenhalt(ctx); + + /* Don't rewrite a block past the end of the FS. */ + if (block >= ext2fs_blocks_count(fs->super)) + return 0; + if (ask(ctx, _("Ignore error"), 1)) { if (ask(ctx, _("Force rewrite"), 1)) io_channel_write_blk64(channel, block, count, data); diff --git a/misc/e2fuzz.sh b/misc/e2fuzz.sh index 4cb7b61..d8d9a82 100755 --- a/misc/e2fuzz.sh +++ b/misc/e2fuzz.sh @@ -219,6 +219,7 @@ seq 1 "${PASSES}" | while read pass; do fi if [ "${RUN_FSCK}" -gt 0 ]; then cp "${PASS_IMG}" "${FSCK_IMG}" + pass_img_sz="$(stat -c '%s' "${PASS_IMG}")" seq 1 "${MAX_FSCK}" | while read fsck_pass; do echo "++ fsck pass ${fsck_pass}: $(which e2fsck) -fy ${FSCK_IMG} ${EXTENDED_FSCK_OPTS}" @@ -250,6 +251,12 @@ seq 1 "${PASSES}" | while read pass; do exit 2 fi fi + + fsck_img_sz="$(stat -c '%s' "${FSCK_IMG}")" + if [ "${fsck_img_sz}" -ne "${pass_img_sz}" ]; then + echo "++ fsck image size changed" + exit 3 + fi done fsck_loop_ret=$? if [ "${fsck_loop_ret}" -gt 0 ]; then