lkml.org 
[lkml]   [2019]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.1 28/70] SUNRPC: Fix a use after free when a server rejects the RPCSEC_GSS credential
Date
From: Trond Myklebust <trond.myklebust@hammerspace.com>

commit 7987b694ade8cc465ce10fb3dceaa614f13ceaf3 upstream.

The addition of rpc_check_timeout() to call_decode causes an Oops
when the RPCSEC_GSS credential is rejected.
The reason is that rpc_decode_header() will call xprt_release() in
order to free task->tk_rqstp, which is needed by rpc_check_timeout()
to check whether or not we should exit due to a soft timeout.

The fix is to move the call to xprt_release() into call_decode() so
we can perform it after rpc_check_timeout().

Reported-by: Olga Kornievskaia <olga.kornievskaia@gmail.com>
Reported-by: Nick Bowler <nbowler@draconx.ca>
Fixes: cea57789e408 ("SUNRPC: Clean up")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/sunrpc/clnt.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)

--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -2387,17 +2387,21 @@ call_decode(struct rpc_task *task)
return;
case -EAGAIN:
task->tk_status = 0;
- /* Note: rpc_decode_header() may have freed the RPC slot */
- if (task->tk_rqstp == req) {
- xdr_free_bvec(&req->rq_rcv_buf);
- req->rq_reply_bytes_recvd = 0;
- req->rq_rcv_buf.len = 0;
- if (task->tk_client->cl_discrtry)
- xprt_conditional_disconnect(req->rq_xprt,
- req->rq_connect_cookie);
- }
+ xdr_free_bvec(&req->rq_rcv_buf);
+ req->rq_reply_bytes_recvd = 0;
+ req->rq_rcv_buf.len = 0;
+ if (task->tk_client->cl_discrtry)
+ xprt_conditional_disconnect(req->rq_xprt,
+ req->rq_connect_cookie);
task->tk_action = call_encode;
rpc_check_timeout(task);
+ break;
+ case -EKEYREJECTED:
+ task->tk_action = call_reserve;
+ rpc_check_timeout(task);
+ rpcauth_invalcred(task);
+ /* Ensure we obtain a new XID if we retry! */
+ xprt_release(task);
}
}

@@ -2533,11 +2537,7 @@ out_msg_denied:
break;
task->tk_cred_retry--;
trace_rpc__stale_creds(task);
- rpcauth_invalcred(task);
- /* Ensure we obtain a new XID! */
- xprt_release(task);
- task->tk_action = call_reserve;
- return -EAGAIN;
+ return -EKEYREJECTED;
case rpc_autherr_badcred:
case rpc_autherr_badverf:
/* possibly garbled cred/verf? */

\
 
 \ /
  Last update: 2019-06-09 18:45    [W:0.336 / U:2.108 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site