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xfs: limit entries returned when counting fsmap records

[ Upstream commit acd1ac3aa2 ]

If userspace asked fsmap to count the number of entries, we cannot
return more than UINT_MAX entries because fmh_entries is u32.
Therefore, stop counting if we hit this limit or else we will waste time
to return truncated results.

Fixes: e89c041338 ("xfs: implement the GETFSMAP ioctl")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Darrick J. Wong 2020-10-01 10:56:07 -07:00 committed by Greg Kroah-Hartman
parent 2577720d35
commit adc3e26986
1 changed files with 3 additions and 0 deletions

View File

@ -255,6 +255,9 @@ xfs_getfsmap_helper(
/* Are we just counting mappings? */
if (info->head->fmh_count == 0) {
if (info->head->fmh_entries == UINT_MAX)
return -ECANCELED;
if (rec_daddr > info->next_daddr)
info->head->fmh_entries++;