This is a note to let you know that I've just added the patch titled xfs: avoid LR buffer overrun due to crafted h_len to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xfs-avoid-lr-buffer-overrun-due-to-crafted-h_len.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b0d1f5d4ecb322ad07487ff945912fe3140ba93f Author: Gao Xiang <hsiangkao@xxxxxxxxxx> Date: Tue Sep 22 09:41:06 2020 -0700 xfs: avoid LR buffer overrun due to crafted h_len [ Upstream commit f692d09e9c8fd0f5557c2e87f796a16dd95222b8 ] Currently, crafted h_len has been blocked for the log header of the tail block in commit a70f9fe52daa ("xfs: detect and handle invalid iclog size set by mkfs"). However, each log record could still have crafted h_len and cause log record buffer overrun. So let's check h_len vs buffer size for each log record as well. Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxx> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c index e2ec91b2d0f46..9ceb67d0f2565 100644 --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -2904,7 +2904,8 @@ STATIC int xlog_valid_rec_header( struct xlog *log, struct xlog_rec_header *rhead, - xfs_daddr_t blkno) + xfs_daddr_t blkno, + int bufsize) { int hlen; @@ -2920,10 +2921,14 @@ xlog_valid_rec_header( return -EFSCORRUPTED; } - /* LR body must have data or it wouldn't have been written */ + /* + * LR body must have data (or it wouldn't have been written) + * and h_len must not be greater than LR buffer size. + */ hlen = be32_to_cpu(rhead->h_len); - if (XFS_IS_CORRUPT(log->l_mp, hlen <= 0 || hlen > INT_MAX)) + if (XFS_IS_CORRUPT(log->l_mp, hlen <= 0 || hlen > bufsize)) return -EFSCORRUPTED; + if (XFS_IS_CORRUPT(log->l_mp, blkno > log->l_logBBsize || blkno > INT_MAX)) return -EFSCORRUPTED; @@ -2984,9 +2989,6 @@ xlog_do_recovery_pass( goto bread_err1; rhead = (xlog_rec_header_t *)offset; - error = xlog_valid_rec_header(log, rhead, tail_blk); - if (error) - goto bread_err1; /* * xfsprogs has a bug where record length is based on lsunit but @@ -3001,21 +3003,18 @@ xlog_do_recovery_pass( */ h_size = be32_to_cpu(rhead->h_size); h_len = be32_to_cpu(rhead->h_len); - if (h_len > h_size) { - if (h_len <= log->l_mp->m_logbsize && - be32_to_cpu(rhead->h_num_logops) == 1) { - xfs_warn(log->l_mp, + if (h_len > h_size && h_len <= log->l_mp->m_logbsize && + rhead->h_num_logops == cpu_to_be32(1)) { + xfs_warn(log->l_mp, "invalid iclog size (%d bytes), using lsunit (%d bytes)", - h_size, log->l_mp->m_logbsize); - h_size = log->l_mp->m_logbsize; - } else { - XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, - log->l_mp); - error = -EFSCORRUPTED; - goto bread_err1; - } + h_size, log->l_mp->m_logbsize); + h_size = log->l_mp->m_logbsize; } + error = xlog_valid_rec_header(log, rhead, tail_blk, h_size); + if (error) + goto bread_err1; + if ((be32_to_cpu(rhead->h_version) & XLOG_VERSION_2) && (h_size > XLOG_HEADER_CYCLE_SIZE)) { hblks = h_size / XLOG_HEADER_CYCLE_SIZE; @@ -3096,7 +3095,7 @@ xlog_do_recovery_pass( } rhead = (xlog_rec_header_t *)offset; error = xlog_valid_rec_header(log, rhead, - split_hblks ? blk_no : 0); + split_hblks ? blk_no : 0, h_size); if (error) goto bread_err2; @@ -3177,7 +3176,7 @@ xlog_do_recovery_pass( goto bread_err2; rhead = (xlog_rec_header_t *)offset; - error = xlog_valid_rec_header(log, rhead, blk_no); + error = xlog_valid_rec_header(log, rhead, blk_no, h_size); if (error) goto bread_err2;