[PATCH AUTOSEL 4.20 076/105] SUNRPC: Ensure we respect the RPCSEC_GSS sequence number limit

[Sasha Levin]

From: Trond Myklebust <tron...@gmail.com>

[ Upstream commit 97b78ae96ba76f4ca2d8f5afee6a2e567ccb8f45 ]

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: Trond Myklebust <trond.mykleb...@hammerspace.com>
Signed-off-by: Anna Schumaker <anna.schuma...@netapp.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 net/sunrpc/auth_gss/auth_gss.c | 12 +++++++++---
 net/sunrpc/clnt.c              | 19 ++++++++++++-------
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index ba765473d1f0..efeee5586b2a 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1563,8 +1563,10 @@ 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);
@@ -1586,14 +1588,18 @@ 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;
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 2189fbc4c570..1ee04e0ec4bc 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1740,11 +1740,8 @@ 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)
@@ -1769,10 +1766,17 @@ call_encode(struct rpc_task *task)
        /* Did the encode result in an error condition? */
        if (task->tk_status != 0) {
                /* Was the error nonfatal? */
-               if (task->tk_status == -EAGAIN || task->tk_status == -ENOMEM)
+               switch (task->tk_status) {
+               case -EAGAIN:
+               case -ENOMEM:
                        rpc_delay(task, HZ >> 4);
-               else
+                       break;
+               case -EKEYEXPIRED:
+                       task->tk_action = call_refresh;
+                       break;
+               default:
                        rpc_exit(task, task->tk_status);
+               }
                return;
        }
 
@@ -2334,7 +2338,8 @@ 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;
 }
 
-- 
2.19.1