[PATCH 4.19 009/152] libceph: handle an empty authorize reply

From: Greg Kroah-Hartman
Date: Mon Feb 25 2019 - 16:58:02 EST


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

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

From: Ilya Dryomov <idryomov@xxxxxxxxx>

commit 0fd3fd0a9bb0b02b6435bb7070e9f7b82a23f068 upstream.

The authorize reply can be empty, for example when the ticket used to
build the authorizer is too old and TAG_BADAUTHORIZER is returned from
the service. Calling ->verify_authorizer_reply() results in an attempt
to decrypt and validate (somewhat) random data in au->buf (most likely
the signature block from calc_signature()), which fails and ends up in
con_fault_finish() with !con->auth_retry. The ticket isn't invalidated
and the connection is retried again and again until a new ticket is
obtained from the monitor:

libceph: osd2 192.168.122.1:6809 bad authorize reply
libceph: osd2 192.168.122.1:6809 bad authorize reply
libceph: osd2 192.168.122.1:6809 bad authorize reply
libceph: osd2 192.168.122.1:6809 bad authorize reply

Let TAG_BADAUTHORIZER handler kick in and increment con->auth_retry.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 5c056fdc5b47 ("libceph: verify authorize reply on connect")
Link: https://tracker.ceph.com/issues/20164
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Reviewed-by: Sage Weil <sage@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/ceph/messenger.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2091,6 +2091,8 @@ static int process_connect(struct ceph_c
dout("process_connect on %p tag %d\n", con, (int)con->in_tag);

if (con->auth) {
+ int len = le32_to_cpu(con->in_reply.authorizer_len);
+
/*
* Any connection that defines ->get_authorizer()
* should also define ->add_authorizer_challenge() and
@@ -2100,8 +2102,7 @@ static int process_connect(struct ceph_c
*/
if (con->in_reply.tag == CEPH_MSGR_TAG_CHALLENGE_AUTHORIZER) {
ret = con->ops->add_authorizer_challenge(
- con, con->auth->authorizer_reply_buf,
- le32_to_cpu(con->in_reply.authorizer_len));
+ con, con->auth->authorizer_reply_buf, len);
if (ret < 0)
return ret;

@@ -2111,10 +2112,12 @@ static int process_connect(struct ceph_c
return 0;
}

- ret = con->ops->verify_authorizer_reply(con);
- if (ret < 0) {
- con->error_msg = "bad authorize reply";
- return ret;
+ if (len) {
+ ret = con->ops->verify_authorizer_reply(con);
+ if (ret < 0) {
+ con->error_msg = "bad authorize reply";
+ return ret;
+ }
}
}