SUNRPC: Add a generic RPC credential

Add an rpc credential that is not tied to any particular auth mechanism,
but that can be cached by NFS, and later used to look up a cred for
whichever auth mechanism that turns out to be valid when the RPC call is
being made.

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

3 files changed, 144 insertions, 1 deletions

diff --git a/net/sunrpc/Makefile b/net/sunrpc/Makefile
index 92e1dbe50947..5369aa369b35 100644
--- a/net/sunrpc/Makefile
+++ b/net/sunrpc/Makefile
@@ -8,7 +8,7 @@ obj-$(CONFIG_SUNRPC_GSS) += auth_gss/
 obj-$(CONFIG_SUNRPC_XPRT_RDMA) += xprtrdma/
 
 sunrpc-y := clnt.o xprt.o socklib.o xprtsock.o sched.o \
-            auth.o auth_null.o auth_unix.o \
+            auth.o auth_null.o auth_unix.o auth_generic.o \
             svc.o svcsock.o svcauth.o svcauth_unix.o \
             rpcb_clnt.o timer.o xdr.o \
             sunrpc_syms.o cache.o rpc_pipe.o \
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 1cdb163c4f89..012f2a320638 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -566,6 +566,7 @@ static struct shrinker rpc_cred_shrinker = {
 void __init rpcauth_init_module(void)
 {
         rpc_init_authunix();
+        rpc_init_generic_auth();
         register_shrinker(&rpc_cred_shrinker);
 }
 
diff --git a/net/sunrpc/auth_generic.c b/net/sunrpc/auth_generic.c
new file mode 100644
index 000000000000..6f129b1b20a0
--- /dev/null
+++ b/net/sunrpc/auth_generic.c
@@ -0,0 +1,142 @@
+/*
+ * Generic RPC credential
+ *
+ * Copyright (C) 2008, Trond Myklebust <Trond.Myklebust@netapp.com>
+ */
+
+#include <linux/err.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/sunrpc/auth.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/debug.h>
+#include <linux/sunrpc/sched.h>
+
+#ifdef RPC_DEBUG
+# define RPCDBG_FACILITY        RPCDBG_AUTH
+#endif
+
+struct generic_cred {
+        struct rpc_cred gc_base;
+        struct auth_cred acred;
+};
+
+static struct rpc_auth generic_auth;
+static struct rpc_cred_cache generic_cred_cache;
+static const struct rpc_credops generic_credops;
+
+/*
+ * Public call interface
+ */
+struct rpc_cred *rpc_lookup_cred(void)
+{
+        return rpcauth_lookupcred(&generic_auth, 0);
+}
+EXPORT_SYMBOL_GPL(rpc_lookup_cred);
+
+/*
+ * Lookup generic creds for current process
+ */
+static struct rpc_cred *
+generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
+{
+        return rpcauth_lookup_credcache(&generic_auth, acred, flags);
+}
+
+static struct rpc_cred *
+generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
+{
+        struct generic_cred *gcred;
+
+        gcred = kmalloc(sizeof(*gcred), GFP_KERNEL);
+        if (gcred == NULL)
+                return ERR_PTR(-ENOMEM);
+
+        rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
+        gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
+
+        gcred->acred.uid = acred->uid;
+        gcred->acred.gid = acred->gid;
+        gcred->acred.group_info = acred->group_info;
+        if (gcred->acred.group_info != NULL)
+                get_group_info(gcred->acred.group_info);
+
+        dprintk("RPC:       allocated generic cred %p for uid %d gid %d\n",
+                        gcred, acred->uid, acred->gid);
+        return &gcred->gc_base;
+}
+
+static void
+generic_free_cred(struct rpc_cred *cred)
+{
+        struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
+
+        dprintk("RPC:       generic_free_cred %p\n", gcred);
+        if (gcred->acred.group_info != NULL)
+                put_group_info(gcred->acred.group_info);
+        kfree(gcred);
+}
+
+static void
+generic_free_cred_callback(struct rcu_head *head)
+{
+        struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
+        generic_free_cred(cred);
+}
+
+static void
+generic_destroy_cred(struct rpc_cred *cred)
+{
+        call_rcu(&cred->cr_rcu, generic_free_cred_callback);
+}
+
+/*
+ * Match credentials against current process creds.
+ */
+static int
+generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
+{
+        struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
+
+        if (gcred->acred.uid != acred->uid ||
+            gcred->acred.gid != acred->gid ||
+            gcred->acred.group_info != acred->group_info)
+                return 0;
+        return 1;
+}
+
+void __init rpc_init_generic_auth(void)
+{
+        spin_lock_init(&generic_cred_cache.lock);
+}
+
+void __exit rpc_destroy_generic_auth(void)
+{
+        rpcauth_clear_credcache(&generic_cred_cache);
+}
+
+static struct rpc_cred_cache generic_cred_cache = {
+        {{ NULL, },},
+};
+
+static const struct rpc_authops generic_auth_ops = {
+        .owner = THIS_MODULE,
+#ifdef RPC_DEBUG
+        .au_name = "Generic",
+#endif
+        .lookup_cred = generic_lookup_cred,
+        .crcreate = generic_create_cred,
+};
+
+static struct rpc_auth generic_auth = {
+        .au_ops = &generic_auth_ops,
+        .au_count = ATOMIC_INIT(0),
+        .au_credcache = &generic_cred_cache,
+};
+
+static const struct rpc_credops generic_credops = {
+        .cr_name = "Generic cred",
+        .crdestroy = generic_destroy_cred,
+        .crmatch = generic_match,
+};