[PATCH 3.16.y-ckt 110/110] udf: Check length of extended attributes and allocation descriptors

[Luis Henriques]

3.16.7-ckt13 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack at suse.cz>

commit 23b133bdc452aa441fcb9b82cbf6dd05cfd342d0 upstream.

Check length of extended attributes and allocation descriptors when
loading inodes from disk. Otherwise corrupted filesystems could confuse
the code and make the kernel oops.

Reported-by: Carl Henrik Lunde <chlunde at ping.uio.no>
Signed-off-by: Jan Kara <jack at suse.cz>
[bwh: Backported to 3.16: use make_bad_inode() instead of returning error]
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/udf/inode.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index c7a5753dc4ec..9a46e23cb769 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1494,6 +1494,19 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
 		iinfo->i_checkpoint = le32_to_cpu(efe->checkpoint);
 	}
 
+	/*
+	 * Sanity check length of allocation descriptors and extended attrs to
+	 * avoid integer overflows
+	 */
+	if (iinfo->i_lenEAttr > bs || iinfo->i_lenAlloc > bs) {
+		make_bad_inode(inode);
+		return;
+	}
+	/* Now do exact checks */
+	if (udf_file_entry_alloc_offset(inode) + iinfo->i_lenAlloc > bs) {
+		make_bad_inode(inode);
+		return;
+	}
 	/* Sanity checks for files in ICB so that we don't get confused later */
 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 		/*