ceph: fix length validation in parse_reply_info()

"len" is read from network and thus needs validation.  Otherwise, given
a bogus "len" value, p+len could be an out-of-bounds pointer, which is
used in further parsing.

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 6203d805eb45..be1415fcaac8 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -262,6 +262,7 @@ static int parse_reply_info(struct ceph_msg *msg,
         /* trace */
         ceph_decode_32_safe(&p, end, len, bad);
         if (len > 0) {
+                ceph_decode_need(&p, end, len, bad);
                 err = parse_reply_info_trace(&p, p+len, info, features);
                 if (err < 0)
                         goto out_bad;
@@ -270,6 +271,7 @@ static int parse_reply_info(struct ceph_msg *msg,
         /* extra */
         ceph_decode_32_safe(&p, end, len, bad);
         if (len > 0) {
+                ceph_decode_need(&p, end, len, bad);
                 err = parse_reply_info_extra(&p, p+len, info, features);
                 if (err < 0)
                         goto out_bad;