SUNRPC: Fix a memory leak in the auth credcache code

The leak only affects the RPCSEC_GSS caches, since they are the only ones
that are dynamically allocated...
Rename the existing rpcauth_free_credcache() to rpcauth_clear_credcache()
in order to better describe its role, then add a new function
rpcauth_destroy_credcache() that actually frees the cache in addition to
clearing it out.

Also move the call to destroy the credcache in gss_destroy() to come before
the rpc upcall pipe is unlinked.

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

4 files changed, 20 insertions, 5 deletions

diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 9527f2bb1744..f6b6c81cbc3e 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -137,9 +137,8 @@ void rpcauth_destroy_credlist(struct hlist_head *head)
  * that are not referenced.
  */
 void
-rpcauth_free_credcache(struct rpc_auth *auth)
+rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 {
-        struct rpc_cred_cache *cache = auth->au_credcache;
         HLIST_HEAD(free);
         struct hlist_node *pos, *next;
         struct rpc_cred *cred;
@@ -157,6 +156,21 @@ rpcauth_free_credcache(struct rpc_auth *auth)
         rpcauth_destroy_credlist(&free);
 }
 
+/*
+ * Destroy the RPC credential cache
+ */
+void
+rpcauth_destroy_credcache(struct rpc_auth *auth)
+{
+        struct rpc_cred_cache *cache = auth->au_credcache;
+
+        if (cache) {
+                auth->au_credcache = NULL;
+                rpcauth_clear_credcache(cache);
+                kfree(cache);
+        }
+}
+
 static void
 rpcauth_prune_expired(struct rpc_auth *auth, struct rpc_cred *cred, struct hlist_head *free)
 {
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 50809086fa1b..8b4c02f8befb 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -665,12 +665,13 @@ gss_destroy(struct rpc_auth *auth)
         dprintk("RPC:       destroying GSS authenticator %p flavor %d\n",
                         auth, auth->au_flavor);
 
+        rpcauth_destroy_credcache(auth);
+
         gss_auth = container_of(auth, struct gss_auth, rpc_auth);
         rpc_unlink(gss_auth->dentry);
         gss_auth->dentry = NULL;
         gss_mech_put(gss_auth->mech);
 
-        rpcauth_free_credcache(auth);
         kfree(gss_auth);
         module_put(THIS_MODULE);
 }
diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index 82300b83045e..5622783011a4 100644
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -50,7 +50,7 @@ static void
 unx_destroy(struct rpc_auth *auth)
 {
         dprintk("RPC:       destroying UNIX authenticator %p\n", auth);
-        rpcauth_free_credcache(auth);
+        rpcauth_clear_credcache(auth->au_credcache);
 }
 
 /*
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index b99b11b11461..3e19e7af6799 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -57,7 +57,7 @@ EXPORT_SYMBOL(rpcauth_unregister);
 EXPORT_SYMBOL(rpcauth_create);
 EXPORT_SYMBOL(rpcauth_lookupcred);
 EXPORT_SYMBOL(rpcauth_lookup_credcache);
-EXPORT_SYMBOL(rpcauth_free_credcache);
+EXPORT_SYMBOL(rpcauth_destroy_credcache);
 EXPORT_SYMBOL(rpcauth_init_credcache);
 EXPORT_SYMBOL(put_rpccred);