[PATCH 3.13.y-ckt 013/122] udf: Check length of extended attributes and allocation descriptors

From: Kamal Mostafa
Date: Wed Jun 17 2015 - 19:02:50 EST


3.13.11-ckt22 -stable 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>
Reference: CVE-2015-4167
BugLink: https://bugs.launchpad.net/bugs/1462173
[ luis: used Ben's backport to 3.16:
- use make_bad_inode() instead of returning error ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
fs/udf/inode.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 8aa2b1b..cfdbbfd 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1480,6 +1480,19 @@ reread:
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) {
/*
--
1.9.1

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