1 files changed, 96 insertions, 20 deletions

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index fe06acd6029b..153b3e11e61a 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -72,7 +72,13 @@ struct gss_auth {
         struct gss_api_mech *mech;
         enum rpc_gss_svc service;
         struct rpc_clnt *client;
-        struct dentry *dentry;
+        /*
+         * There are two upcall pipes; dentry[1], named "gssd", is used
+         * for the new text-based upcall; dentry[0] is named after the
+         * mechanism (for example, "krb5") and exists for
+         * backwards-compatibility with older gssd's.
+         */
+        struct dentry *dentry[2];
 };
 
 /* pipe_version >= 0 if and only if someone has a pipe open. */
@@ -83,7 +89,8 @@ static struct rpc_wait_queue pipe_version_rpc_waitqueue;
 static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
 
 static void gss_free_ctx(struct gss_cl_ctx *);
-static struct rpc_pipe_ops gss_upcall_ops;
+static struct rpc_pipe_ops gss_upcall_ops_v0;
+static struct rpc_pipe_ops gss_upcall_ops_v1;
 
 static inline struct gss_cl_ctx *
 gss_get_ctx(struct gss_cl_ctx *ctx)
@@ -227,6 +234,7 @@ err:
         return p;
 }
 
+#define UPCALL_BUF_LEN 128
 
 struct gss_upcall_msg {
         atomic_t count;
@@ -238,6 +246,7 @@ struct gss_upcall_msg {
         struct rpc_wait_queue rpc_waitqueue;
         wait_queue_head_t waitqueue;
         struct gss_cl_ctx *ctx;
+        char databuf[UPCALL_BUF_LEN];
 };
 
 static int get_pipe_version(void)
@@ -247,7 +256,7 @@ static int get_pipe_version(void)
         spin_lock(&pipe_version_lock);
         if (pipe_version >= 0) {
                 atomic_inc(&pipe_users);
-                ret = 0;
+                ret = pipe_version;
         } else
                 ret = -EAGAIN;
         spin_unlock(&pipe_version_lock);
@@ -353,6 +362,29 @@ gss_upcall_callback(struct rpc_task *task)
         gss_release_msg(gss_msg);
 }
 
+static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg)
+{
+        gss_msg->msg.data = &gss_msg->uid;
+        gss_msg->msg.len = sizeof(gss_msg->uid);
+}
+
+static void gss_encode_v1_msg(struct gss_upcall_msg *gss_msg)
+{
+        gss_msg->msg.len = sprintf(gss_msg->databuf, "mech=%s uid=%d\n",
+                                   gss_msg->auth->mech->gm_name,
+                                   gss_msg->uid);
+        gss_msg->msg.data = gss_msg->databuf;
+        BUG_ON(gss_msg->msg.len > UPCALL_BUF_LEN);
+}
+
+static void gss_encode_msg(struct gss_upcall_msg *gss_msg)
+{
+        if (pipe_version == 0)
+                gss_encode_v0_msg(gss_msg);
+        else /* pipe_version == 1 */
+                gss_encode_v1_msg(gss_msg);
+}
+
 static inline struct gss_upcall_msg *
 gss_alloc_msg(struct gss_auth *gss_auth, uid_t uid)
 {
@@ -367,15 +399,14 @@ gss_alloc_msg(struct gss_auth *gss_auth, uid_t uid)
                 kfree(gss_msg);
                 return ERR_PTR(vers);
         }
-        gss_msg->inode = RPC_I(gss_auth->dentry->d_inode);
+        gss_msg->inode = RPC_I(gss_auth->dentry[vers]->d_inode);
         INIT_LIST_HEAD(&gss_msg->list);
         rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
         init_waitqueue_head(&gss_msg->waitqueue);
         atomic_set(&gss_msg->count, 1);
-        gss_msg->msg.data = &gss_msg->uid;
-        gss_msg->msg.len = sizeof(gss_msg->uid);
         gss_msg->uid = uid;
         gss_msg->auth = gss_auth;
+        gss_encode_msg(gss_msg);
         return gss_msg;
 }
 
@@ -613,18 +644,36 @@ out:
         return err;
 }
 
-static int
-gss_pipe_open(struct inode *inode)
+static int gss_pipe_open(struct inode *inode, int new_version)
 {
+        int ret = 0;
+
         spin_lock(&pipe_version_lock);
         if (pipe_version < 0) {
-                pipe_version = 0;
+                /* First open of any gss pipe determines the version: */
+                pipe_version = new_version;
                 rpc_wake_up(&pipe_version_rpc_waitqueue);
                 wake_up(&pipe_version_waitqueue);
+        } else if (pipe_version != new_version) {
+                /* Trying to open a pipe of a different version */
+                ret = -EBUSY;
+                goto out;
         }
         atomic_inc(&pipe_users);
+out:
         spin_unlock(&pipe_version_lock);
-        return 0;
+        return ret;
+
+}
+
+static int gss_pipe_open_v0(struct inode *inode)
+{
+        return gss_pipe_open(inode, 0);
+}
+
+static int gss_pipe_open_v1(struct inode *inode)
+{
+        return gss_pipe_open(inode, 1);
 }
 
 static void
@@ -702,20 +751,38 @@ gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
         atomic_set(&auth->au_count, 1);
         kref_init(&gss_auth->kref);
 
-        gss_auth->dentry = rpc_mkpipe(clnt->cl_dentry, gss_auth->mech->gm_name,
-                        clnt, &gss_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
-        if (IS_ERR(gss_auth->dentry)) {
-                err = PTR_ERR(gss_auth->dentry);
+        /*
+         * Note: if we created the old pipe first, then someone who
+         * examined the directory at the right moment might conclude
+         * that we supported only the old pipe.  So we instead create
+         * the new pipe first.
+         */
+        gss_auth->dentry[1] = rpc_mkpipe(clnt->cl_dentry,
+                                         "gssd",
+                                         clnt, &gss_upcall_ops_v1,
+                                         RPC_PIPE_WAIT_FOR_OPEN);
+        if (IS_ERR(gss_auth->dentry[1])) {
+                err = PTR_ERR(gss_auth->dentry[1]);
                 goto err_put_mech;
         }
 
+        gss_auth->dentry[0] = rpc_mkpipe(clnt->cl_dentry,
+                                         gss_auth->mech->gm_name,
+                                         clnt, &gss_upcall_ops_v0,
+                                         RPC_PIPE_WAIT_FOR_OPEN);
+        if (IS_ERR(gss_auth->dentry[0])) {
+                err = PTR_ERR(gss_auth->dentry[0]);
+                goto err_unlink_pipe_1;
+        }
         err = rpcauth_init_credcache(auth);
         if (err)
-                goto err_unlink_pipe;
+                goto err_unlink_pipe_0;
 
         return auth;
-err_unlink_pipe:
-        rpc_unlink(gss_auth->dentry);
+err_unlink_pipe_0:
+        rpc_unlink(gss_auth->dentry[0]);
+err_unlink_pipe_1:
+        rpc_unlink(gss_auth->dentry[1]);
 err_put_mech:
         gss_mech_put(gss_auth->mech);
 err_free:
@@ -728,7 +795,8 @@ out_dec:
 static void
 gss_free(struct gss_auth *gss_auth)
 {
-        rpc_unlink(gss_auth->dentry);
+        rpc_unlink(gss_auth->dentry[1]);
+        rpc_unlink(gss_auth->dentry[0]);
         gss_mech_put(gss_auth->mech);
 
         kfree(gss_auth);
@@ -1419,11 +1487,19 @@ static const struct rpc_credops gss_nullops = {
         .crunwrap_resp  = gss_unwrap_resp,
 };
 
-static struct rpc_pipe_ops gss_upcall_ops = {
+static struct rpc_pipe_ops gss_upcall_ops_v0 = {
+        .upcall         = gss_pipe_upcall,
+        .downcall       = gss_pipe_downcall,
+        .destroy_msg    = gss_pipe_destroy_msg,
+        .open_pipe      = gss_pipe_open_v0,
+        .release_pipe   = gss_pipe_release,
+};
+
+static struct rpc_pipe_ops gss_upcall_ops_v1 = {
         .upcall         = gss_pipe_upcall,
         .downcall       = gss_pipe_downcall,
         .destroy_msg    = gss_pipe_destroy_msg,
-        .open_pipe      = gss_pipe_open,
+        .open_pipe      = gss_pipe_open_v1,
         .release_pipe   = gss_pipe_release,
 };