From fac0c8ead88fc91689e18f8f12cfce18bd365ee4 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 27 Jan 2015 12:32:25 -0500 Subject: [PATCH] e2fsck: on read error, don't rewrite blocks past the end of the fs 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 Signed-off-by: Theodore Ts'o --- e2fsck/ehandler.c | 5 +++++ misc/e2fuzz.sh | 7 +++++++ 2 files changed, 12 insertions(+) diff --git a/e2fsck/ehandler.c b/e2fsck/ehandler.c index 6dddf9c1..71ca301c 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 4cb7b61f..d8d9a82a 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