xfs: fix kernel memory exposure problems

Fix a memory exposure problems in inumbers where we allocate an array of
structures with holes, fail to zero the holes, then blindly copy the
kernel memory contents (junk and all) into userspace.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index 2a6d9b1558e00dca550a2d46f8a5a51b9661ec3a..26d67ce3c18d901a85e94836b9e823a5806ae807 100644 (file)
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -583,7 +583,7 @@ xfs_inumbers(
                return error;
 
        bcount = MIN(left, (int)(PAGE_SIZE / sizeof(*buffer)));
-       buffer = kmem_alloc(bcount * sizeof(*buffer), KM_SLEEP);
+       buffer = kmem_zalloc(bcount * sizeof(*buffer), KM_SLEEP);
        do {
                struct xfs_inobt_rec_incore     r;
                int                             stat;