[PATCH 3.2 006/221] udf: Check length of extended attributes and allocation descriptors

[Ben Hutchings]

3.2.69-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Jan Kara <jack@xxxxxxx>

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@xxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
[bwh: Backported to 3.16: use make_bad_inode() instead of returning error]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 fs/udf/inode.c | 9 +++++++++
 1 file changed, 9 insertions(+)

--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1401,6 +1401,19 @@ static void udf_fill_inode(struct inode
 							iinfo->i_lenEAttr;
 	}
 
+	/*
+	 * 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) {
 		/*

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