sunrpc: Hash uids by first computing their value in the initial userns

In svcauth_unix introduce a helper unix_gid_hash as otherwise the
expresion to generate the hash value is just too long.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

2 files changed, 8 insertions, 3 deletions

diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 4cd0ecfe9837..392adc41e2e5 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -412,7 +412,7 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
                         *entry, *new;
         unsigned int nr;
 
-        nr = hash_long(acred->uid, cache->hashbits);
+        nr = hash_long(from_kuid(&init_user_ns, acred->uid), cache->hashbits);
 
         rcu_read_lock();
         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 92166b57ec7a..faf17195a9fd 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -419,6 +419,11 @@ struct unix_gid {
         struct group_info       *gi;
 };
 
+static int unix_gid_hash(kuid_t uid)
+{
+        return hash_long(from_kuid(&init_user_ns, uid), GID_HASHBITS);
+}
+
 static void unix_gid_put(struct kref *kref)
 {
         struct cache_head *item = container_of(kref, struct cache_head, ref);
@@ -530,7 +535,7 @@ static int unix_gid_parse(struct cache_detail *cd,
                 ug.h.expiry_time = expiry;
                 ch = sunrpc_cache_update(cd,
                                          &ug.h, &ugp->h,
-                                         hash_long(uid, GID_HASHBITS));
+                                         unix_gid_hash(uid));
                 if (!ch)
                         err = -ENOMEM;
                 else {
@@ -621,7 +626,7 @@ static struct unix_gid *unix_gid_lookup(struct cache_detail *cd, kuid_t uid)
         struct cache_head *ch;
 
         ug.uid = uid;
-        ch = sunrpc_cache_lookup(cd, &ug.h, hash_long(uid, GID_HASHBITS));
+        ch = sunrpc_cache_lookup(cd, &ug.h, unix_gid_hash(uid));
         if (ch)
                 return container_of(ch, struct unix_gid, h);
         else