SUNRPC: Ensure we respect the RPCSEC_GSS sequence number limit

mainline inclusion
from mainline-v5.0-rc3
commit 97b78ae96ba76f4ca2d8f5afee6a2e567ccb8f45
category: bugfix
bugzilla: 14217
CVE: NA

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

According to RFC2203, the RPCSEC_GSS sequence numbers are bounded to
an upper limit of MAXSEQ = 0x80000000. Ensure that we handle that
correctly.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Conflicts:
	net/sunrpc/clnt.c
762e4e67b356: SUNRPC: Refactor RPC call encoding is not merged,
so it introduced the conflicts.
Signed-off-by: NTrond Myklebust <trondmy@gmail.com>
Signed-off-by: NZhang Xiaoxu <zhangxiaoxu5@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/sunrpc/auth_gss/auth_gss.c

@@ -1540,8 +1540,10 @@ gss_marshal(struct rpc_task *task, __be32 *p)
 	cred_len = p++;
 
 	spin_lock(&ctx->gc_seq_lock);
-	req->rq_seqno = ctx->gc_seq++;
+	req->rq_seqno = (ctx->gc_seq < MAXSEQ) ? ctx->gc_seq++ : MAXSEQ;
 	spin_unlock(&ctx->gc_seq_lock);
+	if (req->rq_seqno == MAXSEQ)
+		goto out_expired;
 
 	*p++ = htonl((u32) RPC_GSS_VERSION);
 	*p++ = htonl((u32) ctx->gc_proc);
@@ -1563,14 +1565,18 @@ gss_marshal(struct rpc_task *task, __be32 *p)
 	mic.data = (u8 *)(p + 1);
 	maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
 	if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
-		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+		goto out_expired;
 	} else if (maj_stat != 0) {
-		printk("gss_marshal: gss_get_mic FAILED (%d)\n", maj_stat);
+		pr_warn("gss_marshal: gss_get_mic FAILED (%d)\n", maj_stat);
+		task->tk_status = -EIO;
 		goto out_put_ctx;
 	}
 	p = xdr_encode_opaque(p, NULL, mic.len);
 	gss_put_ctx(ctx);
 	return p;
+out_expired:
+	clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+	task->tk_status = -EKEYEXPIRED;
 out_put_ctx:
 	gss_put_ctx(ctx);
 	return NULL;

net/sunrpc/clnt.c

@@ -1754,11 +1754,8 @@ rpc_xdr_encode(struct rpc_task *task)
 		     req->rq_rcvsize);
 
 	p = rpc_encode_header(task);
-	if (p == NULL) {
-		printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
-		rpc_exit(task, -EIO);
+	if (p == NULL)
 		return;
-	}
 
 	encode = task->tk_msg.rpc_proc->p_encode;
 	if (encode == NULL)
@@ -1965,6 +1962,8 @@ call_transmit(struct rpc_task *task)
 			/* Was the error nonfatal? */
 			if (task->tk_status == -EAGAIN)
 				rpc_delay(task, HZ >> 4);
+			else if (task->tk_status == -EKEYEXPIRED)
+				task->tk_action = call_refresh;
 			else
 				rpc_exit(task, task->tk_status);
 			return;
@@ -2338,7 +2337,8 @@ rpc_encode_header(struct rpc_task *task)
 	*p++ = htonl(clnt->cl_vers);	/* program version */
 	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
 	p = rpcauth_marshcred(task, p);
-	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
+	if (p)
+		req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
 	return p;
 }