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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 a70f9fe52d ("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@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
This commit is contained in:
Gao Xiang 2020-09-22 09:41:06 -07:00 committed by Darrick J. Wong
parent 384ff09ba2
commit f692d09e9c
1 changed files with 19 additions and 20 deletions
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39
fs/xfs/xfs_log_recover.c
View File

@ -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;