This is a note to let you know that I've just added the patch titled xfs: fix boundary test in xfs_attr_shortform_verify to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xfs-fix-boundary-test-in-xfs_attr_shortform_verify.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 7294e9609f15b783e020e09321736c3f04fb69e9 Author: Eric Sandeen <sandeen@xxxxxxxxxx> Date: Wed Aug 26 14:11:58 2020 -0700 xfs: fix boundary test in xfs_attr_shortform_verify [ 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@xxxxxxxxxx> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> 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. */