From f692d09e9c8fd0f5557c2e87f796a16dd95222b8 Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Tue, 22 Sep 2020 09:41:06 -0700 Subject: [PATCH] xfs: avoid LR buffer overrun due to crafted h_len 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 Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster --- fs/xfs/xfs_log_recover.c | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-) diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c index a17d788..782ec3e 100644 --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -2878,7 +2878,8 @@ 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; @@ -2894,10 +2895,14 @@ 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; @@ -2958,9 +2963,6 @@ 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 @@ -2975,21 +2977,18 @@ 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; @@ -3070,7 +3069,7 @@ 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; @@ -3151,7 +3150,7 @@ 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; -- 2.7.4