From: Eric Sandeen sandeen@redhat.com
[ Upstream commit f4020438fab05364018c91f7e02ebdd192085933 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/xfs/libxfs/xfs_attr_leaf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c index f0089e862216c..fe277ee5ec7c4 100644 --- a/fs/xfs/libxfs/xfs_attr_leaf.c +++ b/fs/xfs/libxfs/xfs_attr_leaf.c @@ -946,8 +946,10 @@ 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. */