SUNRPC: Move upcall out of auth->au_ops->crcreate()

 This fixes a bug whereby if two processes try to look up the same auth_gss
 credential, they may end up creating two creds, and triggering two upcalls
 because the upcall is performed before the credential is added to the
 credcache.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 23 insertions, 9 deletions

diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
index bfc5fb279539..2647798b72c7 100644
--- a/include/linux/sunrpc/auth.h
+++ b/include/linux/sunrpc/auth.h
@@ -110,6 +110,7 @@ struct rpc_authops {
 
 struct rpc_credops {
         const char *            cr_name;        /* Name of the auth flavour */
+        int                     (*cr_init)(struct rpc_auth *, struct rpc_cred *);
         void                    (*crdestroy)(struct rpc_cred *);
 
         int                     (*crmatch)(struct auth_cred *, struct rpc_cred *, int);
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 1ca89c36da7a..8d6f1a176b15 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -232,6 +232,14 @@ retry:
                         goto retry;
                 } else
                         cred = new;
+        } else if ((cred->cr_flags & RPCAUTH_CRED_NEW)
+                        && cred->cr_ops->cr_init != NULL
+                        && !(flags & RPCAUTH_LOOKUP_NEW)) {
+                int res = cred->cr_ops->cr_init(auth, cred);
+                if (res < 0) {
+                        put_rpccred(cred);
+                        cred = ERR_PTR(res);
+                }
         }
 
         return (struct rpc_cred *) cred;
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 03affcbf6292..bb46efd92e57 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -788,15 +788,6 @@ gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
         cred->gc_base.cr_ops = &gss_credops;
         cred->gc_base.cr_flags = RPCAUTH_CRED_NEW;
         cred->gc_service = gss_auth->service;
-        /* Is the caller prepared to initialise the credential? */
-        if (flags & RPCAUTH_LOOKUP_NEW)
-                goto out;
-        do {
-                err = gss_create_upcall(gss_auth, cred);
-        } while (err == -EAGAIN);
-        if (err < 0)
-                goto out_err;
-out:
         return &cred->gc_base;
 
 out_err:
@@ -806,6 +797,19 @@ out_err:
 }
 
 static int
+gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
+{
+        struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
+        struct gss_cred *gss_cred = container_of(cred,struct gss_cred, gc_base);
+        int err;
+
+        do {
+                err = gss_create_upcall(gss_auth, gss_cred);
+        } while (err == -EAGAIN);
+        return err;
+}
+
+static int
 gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
 {
         struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
@@ -1254,6 +1258,7 @@ static struct rpc_authops authgss_ops = {
 static struct rpc_credops gss_credops = {
         .cr_name        = "AUTH_GSS",
         .crdestroy      = gss_destroy_cred,
+        .cr_init        = gss_cred_init,
         .crmatch        = gss_match,
         .crmarshal      = gss_marshal,
         .crrefresh      = gss_refresh,