From: Theodore Ts'o Date: Tue, 2 Oct 2018 05:34:44 +0000 (-0400) Subject: ext4: fix argument checking in EXT4_IOC_MOVE_EXT X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=f18b2b83a727a3db208308057d2c7945f368e625;p=openwrt%2Fstaging%2Fblogic.git ext4: fix argument checking in EXT4_IOC_MOVE_EXT If the starting block number of either the source or destination file exceeds the EOF, EXT4_IOC_MOVE_EXT should return EINVAL. Also fixed the helper function mext_check_coverage() so that if the logical block is beyond EOF, make it return immediately, instead of looping until the block number wraps all the away around. This takes long enough that if there are multiple threads trying to do pound on an the same inode doing non-sensical things, it can end up triggering the kernel's soft lockup detector. Reported-by: syzbot+c61979f6f2cba5cb3c06@syzkaller.appspotmail.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org --- diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index a409ff70d67b..2f5be02fc6f6 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -516,9 +516,13 @@ mext_check_arguments(struct inode *orig_inode, orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } - if (orig_eof < orig_start + *len - 1) + if (orig_eof <= orig_start) + *len = 0; + else if (orig_eof < orig_start + *len - 1) *len = orig_eof - orig_start; - if (donor_eof < donor_start + *len - 1) + if (donor_eof <= donor_start) + *len = 0; + else if (donor_eof < donor_start + *len - 1) *len = donor_eof - donor_start; if (!*len) { ext4_debug("ext4 move extent: len should not be 0 "