Subject: [PATCH 2.6.32 11/12] udf: Check length of extended attributes and allocation descriptors

From: Jan Kara <[email-masked]>
Date: Wed, 7 Jan 2015 13:49:08 +0100

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 <[email-masked]>
Signed-off-by: Jan Kara <[email-masked]>
[bwh: Backported to 2.6.32: use make_bad_inode() instead of returning error]
Signed-off-by: Ben Hutchings <[email-masked]>
---
 fs/udf/inode.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 26b7f31..b8d7a0e 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1284,6 +1284,19 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
 							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) {
 		/*