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authorEric Sandeen <sandeen@redhat.com>2020-08-27 00:11:58 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2020-08-27 00:13:21 +0300
commitf4020438fab05364018c91f7e02ebdd192085933 (patch)
tree41d1a045a0aad864a63228e69a41b936136fbe08 /fs
parent657f101930bc6c5b41bd7d6c22565c4302a80d33 (diff)
downloadlinux-f4020438fab05364018c91f7e02ebdd192085933.tar.xz
xfs: fix boundary test in xfs_attr_shortform_verify
The boundary test for the fixed-offset parts of xfs_attr_sf_entry in xfs_attr_shortform_verify is off by one, because the variable array at the end is defined as nameval[1] not nameval[]. Hence we need to subtract 1 from the calculation. This can be shown by: # touch file # setfattr -n root.a file and verifications will fail when it's written to disk. This only matters for a last attribute which has a single-byte name and no value, otherwise the combination of namelen & valuelen will push endp further out and this test won't fail. Fixes: 1e1bbd8e7ee06 ("xfs: create structure verifier function for shortform xattrs") Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs')
-rw-r--r--fs/xfs/libxfs/xfs_attr_leaf.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 8623c815164a..383b08f2ac61 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -1036,8 +1036,10 @@ xfs_attr_shortform_verify(
* struct xfs_attr_sf_entry has a variable length.
* Check the fixed-offset parts of the structure are
* within the data buffer.
+ * xfs_attr_sf_entry is defined with a 1-byte variable
+ * array at the end, so we must subtract that off.
*/
- if (((char *)sfep + sizeof(*sfep)) >= endp)
+ if (((char *)sfep + sizeof(*sfep) - 1) >= endp)
return __this_address;
/* Don't allow names with known bad length. */