RPCSEC_GSS: Fix an Oopsable condition when creating/destroying pipefs objects

If an error condition occurs on rpc_pipefs creation, or the user mounts
rpc_pipefs and then unmounts it, then the dentries in struct gss_auth
need to be reset to NULL so that a second call to gss_pipes_dentries_destroy
doesn't try to free them again.

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

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 6323803..c0d36bb 100644 (file)
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -796,10 +796,14 @@ static void gss_pipes_dentries_destroy(struct rpc_auth *auth)
        struct gss_auth *gss_auth;
 
        gss_auth = container_of(auth, struct gss_auth, rpc_auth);
-       if (gss_auth->pipe[0]->dentry)
+       if (gss_auth->pipe[0]->dentry) {
                rpc_unlink(gss_auth->pipe[0]->dentry);
-       if (gss_auth->pipe[1]->dentry)
+               gss_auth->pipe[0]->dentry = NULL;
+       }
+       if (gss_auth->pipe[1]->dentry) {
                rpc_unlink(gss_auth->pipe[1]->dentry);
+               gss_auth->pipe[1]->dentry = NULL;
+       }
 }
 
 static int gss_pipes_dentries_create(struct rpc_auth *auth)
@@ -807,26 +811,30 @@ static int gss_pipes_dentries_create(struct rpc_auth *auth)
        int err;
        struct gss_auth *gss_auth;
        struct rpc_clnt *clnt;
+       struct dentry *dentry;
 
        gss_auth = container_of(auth, struct gss_auth, rpc_auth);
        clnt = gss_auth->client;
 
-       gss_auth->pipe[1]->dentry = rpc_mkpipe_dentry(clnt->cl_dentry,
-                                                     "gssd",
-                                                     clnt, gss_auth->pipe[1]);
-       if (IS_ERR(gss_auth->pipe[1]->dentry))
-               return PTR_ERR(gss_auth->pipe[1]->dentry);
-       gss_auth->pipe[0]->dentry = rpc_mkpipe_dentry(clnt->cl_dentry,
-                                                     gss_auth->mech->gm_name,
-                                                     clnt, gss_auth->pipe[0]);
-       if (IS_ERR(gss_auth->pipe[0]->dentry)) {
-               err = PTR_ERR(gss_auth->pipe[0]->dentry);
+       dentry = rpc_mkpipe_dentry(clnt->cl_dentry, "gssd",
+                       clnt, gss_auth->pipe[1]);
+       if (IS_ERR(dentry)) {
+               err = PTR_ERR(dentry);
+               goto err;
+       }
+       gss_auth->pipe[1]->dentry = dentry;
+       dentry = rpc_mkpipe_dentry(clnt->cl_dentry, gss_auth->mech->gm_name,
+                       clnt, gss_auth->pipe[0]);
+       if (IS_ERR(dentry)) {
+               err = PTR_ERR(dentry);
                goto err_unlink_pipe_1;
        }
        return 0;
 
 err_unlink_pipe_1:
        rpc_unlink(gss_auth->pipe[1]->dentry);
+       gss_auth->pipe[1]->dentry = NULL;
+err:
        return err;
 }