RPCSEC_GSS: cleanup au_rslack calculation

 Various xdr encode routines use au_rslack to guess where the reply argument
 will end up, so we can set up the xdr_buf to recieve data into the right place
 for zero copy.

 Currently we calculate the au_rslack estimate when we check the verifier.
 Normally this only depends on the verifier size.  In the integrity case we add
 a few bytes to allow for a length and sequence number.

 It's a bit simpler to calculate only the verifier size when we check the
 verifier, and delay the full calculation till we unwrap.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 6 insertions, 14 deletions

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index d2b08f16c257..dc95b797ca65 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -886,8 +886,6 @@ static u32 *
 gss_validate(struct rpc_task *task, u32 *p)
 {
         struct rpc_cred *cred = task->tk_msg.rpc_cred;
-        struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
-                                                gc_base);
         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
         u32             seq, qop_state;
         struct kvec     iov;
@@ -915,18 +913,9 @@ gss_validate(struct rpc_task *task, u32 *p)
                 cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
         if (maj_stat)
                 goto out_bad;
-       switch (gss_cred->gc_service) {
-       case RPC_GSS_SVC_NONE:
-               /* verifier data, flavor, length: */
-               task->tk_auth->au_rslack = XDR_QUADLEN(len) + 2;
-               break;
-       case RPC_GSS_SVC_INTEGRITY:
-               /* verifier data, flavor, length, length, sequence number: */
-               task->tk_auth->au_rslack = XDR_QUADLEN(len) + 4;
-               break;
-       case RPC_GSS_SVC_PRIVACY:
-               goto out_bad;
-       }
+        /* We leave it to unwrap to calculate au_rslack. For now we just
+         * calculate the length of the verifier: */
+        task->tk_auth->au_verfsize = XDR_QUADLEN(len) + 2;
         gss_put_ctx(ctx);
         dprintk("RPC: %4u GSS gss_validate: gss_verify_mic succeeded.\n",
                         task->tk_pid);
@@ -1067,6 +1056,7 @@ gss_unwrap_resp(struct rpc_task *task,
         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
                         gc_base);
         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
+        u32             *savedp = p;
         int             status = -EIO;
 
         if (ctx->gc_proc != RPC_GSS_PROC_DATA)
@@ -1082,6 +1072,8 @@ gss_unwrap_resp(struct rpc_task *task,
                 case RPC_GSS_SVC_PRIVACY:
                         break;
         }
+        /* take into account extra slack for integrity and privacy cases: */
+        task->tk_auth->au_rslack = task->tk_auth->au_verfsize + (p - savedp);
 out_decode:
         status = decode(rqstp, p, obj);
 out: