[PATCH] kNFSd: rsc_lookup simplification

rsc_lookup is a bit complicated: it either takes responsibility for the memory
pointed to by handle.data and sets handle.data to NULL, or it leaves
handle.data unchanged, in which case the caller is responsible for freeing
handle.data.  I forgot that the possibility of inserting a negative cache
entry into the cache meant that this could happen even when rsc_lookup is
called with set == 0.

Note that the ip_map code has the same bug, not that it seems to matter much,
since the memory in question in that case is always just a statically
allocated string.

From: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

net/sunrpc/auth_gss/svcauth_gss.c

@@ -333,6 +333,7 @@ rsc_init(struct rsc *new, struct rsc *tmp)
 	new->handle.data = tmp->handle.data;
 	tmp->handle.data = NULL;
 	new->mechctx = NULL;
+	new->cred.cr_group_info = NULL;
 }
 
 static inline void
@@ -453,8 +454,11 @@ gss_svc_searchbyctx(struct xdr_netobj *handle)
 	struct rsc rsci;
 	struct rsc *found;
 
-	rsci.handle = *handle;
+	memset(&rsci, 0, sizeof(rsci));
+	if (dup_to_netobj(&rsci.handle, handle->data, handle->len))
+		return NULL;
 	found = rsc_lookup(&rsci, 0);
+	rsc_free(&rsci);
 	if (!found)
 		return NULL;
 	if (cache_check(&rsc_cache, &found->h, NULL))