From ba9b584c1dc37851d9c6ca6d0d2ccba55d9aad04 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 14 Sep 2012 17:24:02 -0400 Subject: [PATCH] SUNRPC: Introduce rpc_clone_client_set_auth() An ULP is supposed to be able to replace a GSS rpc_auth object with another GSS rpc_auth object using rpcauth_create(). However, rpcauth_create() in 3.5 reliably fails with -EEXIST in this case. This is because when gss_create() attempts to create the upcall pipes, sometimes they are already there. For example if a pipe FS mount event occurs, or a previous GSS flavor was in use for this rpc_clnt. It turns out that's not the only problem here. While working on a fix for the above problem, we noticed that replacing an rpc_clnt's rpc_auth is not safe, since dereferencing the cl_auth field is not protected in any way. So we're deprecating the ability of rpcauth_create() to switch an rpc_clnt's security flavor during normal operation. Instead, let's add a fresh API that clones an rpc_clnt and gives the clone a new flavor before it's used. This makes immediate use of the new __rpc_clone_client() helper. This can be used in a similar fashion to rpcauth_create() when a client is hunting for the correct security flavor. Instead of replacing an rpc_clnt's security flavor in a loop, the ULP replaces the whole rpc_clnt. To fix the -EEXIST problem, any ULP logic that relies on replacing an rpc_clnt's rpc_auth with rpcauth_create() must be changed to use this API instead. Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/client.c | 13 ++----------- fs/nfs/nfs4namespace.c | 14 +------------- include/linux/sunrpc/clnt.h | 2 ++ net/sunrpc/clnt.c | 22 ++++++++++++++++++++++ 4 files changed, 27 insertions(+), 24 deletions(-) diff --git a/fs/nfs/client.c b/fs/nfs/client.c index 99694442b93f..143149db3440 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -668,7 +668,8 @@ int nfs_init_server_rpcclient(struct nfs_server *server, { struct nfs_client *clp = server->nfs_client; - server->client = rpc_clone_client(clp->cl_rpcclient); + server->client = rpc_clone_client_set_auth(clp->cl_rpcclient, + pseudoflavour); if (IS_ERR(server->client)) { dprintk("%s: couldn't create rpc_client!\n", __func__); return PTR_ERR(server->client); @@ -678,16 +679,6 @@ int nfs_init_server_rpcclient(struct nfs_server *server, timeo, sizeof(server->client->cl_timeout_default)); server->client->cl_timeout = &server->client->cl_timeout_default; - - if (pseudoflavour != clp->cl_rpcclient->cl_auth->au_flavor) { - struct rpc_auth *auth; - - auth = rpcauth_create(pseudoflavour, server->client); - if (IS_ERR(auth)) { - dprintk("%s: couldn't create credcache!\n", __func__); - return PTR_ERR(auth); - } - } server->client->cl_softrtry = 0; if (server->flags & NFS_MOUNT_SOFT) server->client->cl_softrtry = 1; diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c index 4fdeb1b7042e..79fbb61ce202 100644 --- a/fs/nfs/nfs4namespace.c +++ b/fs/nfs/nfs4namespace.c @@ -192,25 +192,13 @@ out: struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode, struct qstr *name) { - struct rpc_clnt *clone; - struct rpc_auth *auth; rpc_authflavor_t flavor; flavor = nfs4_negotiate_security(inode, name); if ((int)flavor < 0) return ERR_PTR((int)flavor); - clone = rpc_clone_client(clnt); - if (IS_ERR(clone)) - return clone; - - auth = rpcauth_create(flavor, clone); - if (IS_ERR(auth)) { - rpc_shutdown_client(clone); - clone = ERR_PTR(-EIO); - } - - return clone; + return rpc_clone_client_set_auth(clnt, flavor); } static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h index 523547ecfee2..34206b84d8da 100644 --- a/include/linux/sunrpc/clnt.h +++ b/include/linux/sunrpc/clnt.h @@ -130,6 +130,8 @@ struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *, const struct rpc_program *, u32); void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt); struct rpc_clnt *rpc_clone_client(struct rpc_clnt *); +struct rpc_clnt *rpc_clone_client_set_auth(struct rpc_clnt *, + rpc_authflavor_t); void rpc_shutdown_client(struct rpc_clnt *); void rpc_release_client(struct rpc_clnt *); void rpc_task_release_client(struct rpc_task *); diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index afbeefab6600..cdc7564b4512 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -548,6 +548,28 @@ struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt) } EXPORT_SYMBOL_GPL(rpc_clone_client); +/** + * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth + * + * @clnt: RPC client whose parameters are copied + * @auth: security flavor for new client + * + * Returns a fresh RPC client or an ERR_PTR. + */ +struct rpc_clnt * +rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor) +{ + struct rpc_create_args args = { + .program = clnt->cl_program, + .prognumber = clnt->cl_prog, + .version = clnt->cl_vers, + .authflavor = flavor, + .client_name = clnt->cl_principal, + }; + return __rpc_clone_client(&args, clnt); +} +EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth); + /* * Kill all tasks for the given client. * XXX: kill their descendants as well? -- 2.20.1