On Tue, Nov 23, 2021 at 11:57:04AM -0500, J. Bruce Fields wrote:
> From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
>
> This code exists only for compatibility with nfs-utils before
> 0cfdc66de043 "gssd: handle new client upcall" (which first appeared in
> nfs-utils version 1.2.2, in 2009). After 12 years, maybe it's time to
> drop that compatibility code.
Are you interested in this? Should I resend?
--b.
>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> ---
> include/linux/sunrpc/rpc_pipe_fs.h | 1 -
> net/sunrpc/auth_gss/auth_gss.c | 165 ++---------------------------
> net/sunrpc/rpc_pipe.c | 7 --
> 3 files changed, 7 insertions(+), 166 deletions(-)
>
> On Sat, Oct 02, 2021 at 08:07:20PM -0400, J. Bruce Fields wrote:
> > (Whoops, somebody just pointed out a typo'd a year--that 2019 should
> > obviously be 2009.
>
> Resending with that typo fixed. Can we get this in 5.17? I think it'd
> make life just a little easier for the next person that has to mess with
> this code.
>
> --b.
>
> diff --git a/include/linux/sunrpc/rpc_pipe_fs.h b/include/linux/sunrpc/rpc_pipe_fs.h
> index cd188a527d16..f8a11d1cfbf8 100644
> --- a/include/linux/sunrpc/rpc_pipe_fs.h
> +++ b/include/linux/sunrpc/rpc_pipe_fs.h
> @@ -36,7 +36,6 @@ struct rpc_pipe_ops {
> ssize_t (*upcall)(struct file *, struct rpc_pipe_msg *, char __user *, size_t);
> ssize_t (*downcall)(struct file *, const char __user *, size_t);
> void (*release_pipe)(struct inode *);
> - int (*open_pipe)(struct inode *);
> void (*destroy_msg)(struct rpc_pipe_msg *);
> };
>
> diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
> index 5f42aa5fc612..71fd2fb7c5fb 100644
> --- a/net/sunrpc/auth_gss/auth_gss.c
> +++ b/net/sunrpc/auth_gss/auth_gss.c
> @@ -73,24 +73,13 @@ struct gss_auth {
> enum rpc_gss_svc service;
> struct rpc_clnt *client;
> struct net *net;
> - /*
> - * 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 gss_pipe *gss_pipe[2];
> + struct gss_pipe *gss_pipe;
> const char *target_name;
> };
>
> -/* pipe_version >= 0 if and only if someone has a pipe open. */
> -static DEFINE_SPINLOCK(pipe_version_lock);
> -static struct rpc_wait_queue pipe_version_rpc_waitqueue;
> -static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
> static void gss_put_auth(struct gss_auth *gss_auth);
>
> static void gss_free_ctx(struct gss_cl_ctx *);
> -static const struct rpc_pipe_ops gss_upcall_ops_v0;
> static const struct rpc_pipe_ops gss_upcall_ops_v1;
>
> static inline struct gss_cl_ctx *
> @@ -253,38 +242,11 @@ struct gss_upcall_msg {
> char databuf[UPCALL_BUF_LEN];
> };
>
> -static int get_pipe_version(struct net *net)
> -{
> - struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
> - int ret;
> -
> - spin_lock(&pipe_version_lock);
> - if (sn->pipe_version >= 0) {
> - atomic_inc(&sn->pipe_users);
> - ret = sn->pipe_version;
> - } else
> - ret = -EAGAIN;
> - spin_unlock(&pipe_version_lock);
> - return ret;
> -}
> -
> -static void put_pipe_version(struct net *net)
> -{
> - struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
> -
> - if (atomic_dec_and_lock(&sn->pipe_users, &pipe_version_lock)) {
> - sn->pipe_version = -1;
> - spin_unlock(&pipe_version_lock);
> - }
> -}
> -
> static void
> gss_release_msg(struct gss_upcall_msg *gss_msg)
> {
> - struct net *net = gss_msg->auth->net;
> if (!refcount_dec_and_test(&gss_msg->count))
> return;
> - put_pipe_version(net);
> BUG_ON(!list_empty(&gss_msg->list));
> if (gss_msg->ctx != NULL)
> gss_put_ctx(gss_msg->ctx);
> @@ -385,31 +347,6 @@ gss_upcall_callback(struct rpc_task *task)
> gss_release_msg(gss_msg);
> }
>
> -static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg,
> - const struct cred *cred)
> -{
> - struct user_namespace *userns = cred->user_ns;
> -
> - uid_t uid = from_kuid_munged(userns, gss_msg->uid);
> - memcpy(gss_msg->databuf, &uid, sizeof(uid));
> - gss_msg->msg.data = gss_msg->databuf;
> - gss_msg->msg.len = sizeof(uid);
> -
> - BUILD_BUG_ON(sizeof(uid) > sizeof(gss_msg->databuf));
> -}
> -
> -static ssize_t
> -gss_v0_upcall(struct file *file, struct rpc_pipe_msg *msg,
> - char __user *buf, size_t buflen)
> -{
> - struct gss_upcall_msg *gss_msg = container_of(msg,
> - struct gss_upcall_msg,
> - msg);
> - if (msg->copied == 0)
> - gss_encode_v0_msg(gss_msg, file->f_cred);
> - return rpc_pipe_generic_upcall(file, msg, buf, buflen);
> -}
> -
> static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
> const char *service_name,
> const char *target_name,
> @@ -507,17 +444,12 @@ gss_alloc_msg(struct gss_auth *gss_auth,
> kuid_t uid, const char *service_name)
> {
> struct gss_upcall_msg *gss_msg;
> - int vers;
> int err = -ENOMEM;
>
> gss_msg = kzalloc(sizeof(*gss_msg), GFP_NOFS);
> if (gss_msg == NULL)
> goto err;
> - vers = get_pipe_version(gss_auth->net);
> - err = vers;
> - if (err < 0)
> - goto err_free_msg;
> - gss_msg->pipe = gss_auth->gss_pipe[vers]->pipe;
> + gss_msg->pipe = gss_auth->gss_pipe->pipe;
> INIT_LIST_HEAD(&gss_msg->list);
> rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
> init_waitqueue_head(&gss_msg->waitqueue);
> @@ -529,12 +461,10 @@ gss_alloc_msg(struct gss_auth *gss_auth,
> gss_msg->service_name = kstrdup_const(service_name, GFP_NOFS);
> if (!gss_msg->service_name) {
> err = -ENOMEM;
> - goto err_put_pipe_version;
> + goto err_free_msg;
> }
> }
> return gss_msg;
> -err_put_pipe_version:
> - put_pipe_version(gss_auth->net);
> err_free_msg:
> kfree(gss_msg);
> err:
> @@ -590,8 +520,6 @@ gss_refresh_upcall(struct rpc_task *task)
> /* XXX: warning on the first, under the assumption we
> * shouldn't normally hit this case on a refresh. */
> warn_gssd();
> - rpc_sleep_on_timeout(&pipe_version_rpc_waitqueue,
> - task, NULL, jiffies + (15 * HZ));
> err = -EAGAIN;
> goto out;
> }
> @@ -624,14 +552,12 @@ static inline int
> gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
> {
> struct net *net = gss_auth->net;
> - struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
> struct rpc_pipe *pipe;
> struct rpc_cred *cred = &gss_cred->gc_base;
> struct gss_upcall_msg *gss_msg;
> DEFINE_WAIT(wait);
> int err;
>
> -retry:
> err = 0;
> /* if gssd is down, just skip upcalling altogether */
> if (!gssd_running(net)) {
> @@ -640,17 +566,6 @@ gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
> goto out;
> }
> gss_msg = gss_setup_upcall(gss_auth, cred);
> - if (PTR_ERR(gss_msg) == -EAGAIN) {
> - err = wait_event_interruptible_timeout(pipe_version_waitqueue,
> - sn->pipe_version >= 0, 15 * HZ);
> - if (sn->pipe_version < 0) {
> - warn_gssd();
> - err = -EACCES;
> - }
> - if (err < 0)
> - goto out;
> - goto retry;
> - }
> if (IS_ERR(gss_msg)) {
> err = PTR_ERR(gss_msg);
> goto out;
> @@ -777,44 +692,9 @@ gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
> return err;
> }
>
> -static int gss_pipe_open(struct inode *inode, int new_version)
> -{
> - struct net *net = inode->i_sb->s_fs_info;
> - struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
> - int ret = 0;
> -
> - spin_lock(&pipe_version_lock);
> - if (sn->pipe_version < 0) {
> - /* First open of any gss pipe determines the version: */
> - sn->pipe_version = new_version;
> - rpc_wake_up(&pipe_version_rpc_waitqueue);
> - wake_up(&pipe_version_waitqueue);
> - } else if (sn->pipe_version != new_version) {
> - /* Trying to open a pipe of a different version */
> - ret = -EBUSY;
> - goto out;
> - }
> - atomic_inc(&sn->pipe_users);
> -out:
> - spin_unlock(&pipe_version_lock);
> - 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
> gss_pipe_release(struct inode *inode)
> {
> - struct net *net = inode->i_sb->s_fs_info;
> struct rpc_pipe *pipe = RPC_I(inode)->pipe;
> struct gss_upcall_msg *gss_msg;
>
> @@ -832,8 +712,6 @@ gss_pipe_release(struct inode *inode)
> goto restart;
> }
> spin_unlock(&pipe->lock);
> -
> - put_pipe_version(net);
> }
>
> static void
> @@ -1039,30 +917,14 @@ gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
> err = rpcauth_init_credcache(auth);
> if (err)
> goto err_put_mech;
> - /*
> - * 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_pipe = gss_pipe_get(clnt, "gssd", &gss_upcall_ops_v1);
> if (IS_ERR(gss_pipe)) {
> err = PTR_ERR(gss_pipe);
> goto err_destroy_credcache;
> }
> - gss_auth->gss_pipe[1] = gss_pipe;
> -
> - gss_pipe = gss_pipe_get(clnt, gss_auth->mech->gm_name,
> - &gss_upcall_ops_v0);
> - if (IS_ERR(gss_pipe)) {
> - err = PTR_ERR(gss_pipe);
> - goto err_destroy_pipe_1;
> - }
> - gss_auth->gss_pipe[0] = gss_pipe;
> + gss_auth->gss_pipe = gss_pipe;
>
> return gss_auth;
> -err_destroy_pipe_1:
> - gss_pipe_free(gss_auth->gss_pipe[1]);
> err_destroy_credcache:
> rpcauth_destroy_credcache(auth);
> err_put_mech:
> @@ -1081,8 +943,7 @@ gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
> static void
> gss_free(struct gss_auth *gss_auth)
> {
> - gss_pipe_free(gss_auth->gss_pipe[0]);
> - gss_pipe_free(gss_auth->gss_pipe[1]);
> + gss_pipe_free(gss_auth->gss_pipe);
> gss_mech_put(gss_auth->mech);
> put_net(gss_auth->net);
> kfree(gss_auth->target_name);
> @@ -1117,10 +978,8 @@ gss_destroy(struct rpc_auth *auth)
> spin_unlock(&gss_auth_hash_lock);
> }
>
> - gss_pipe_free(gss_auth->gss_pipe[0]);
> - gss_auth->gss_pipe[0] = NULL;
> - gss_pipe_free(gss_auth->gss_pipe[1]);
> - gss_auth->gss_pipe[1] = NULL;
> + gss_pipe_free(gss_auth->gss_pipe);
> + gss_auth->gss_pipe = NULL;
> rpcauth_destroy_credcache(auth);
>
> gss_put_auth(gss_auth);
> @@ -2179,19 +2038,10 @@ static const struct rpc_credops gss_nullops = {
> .crstringify_acceptor = gss_stringify_acceptor,
> };
>
> -static const struct rpc_pipe_ops gss_upcall_ops_v0 = {
> - .upcall = gss_v0_upcall,
> - .downcall = gss_pipe_downcall,
> - .destroy_msg = gss_pipe_destroy_msg,
> - .open_pipe = gss_pipe_open_v0,
> - .release_pipe = gss_pipe_release,
> -};
> -
> static const struct rpc_pipe_ops gss_upcall_ops_v1 = {
> .upcall = gss_v1_upcall,
> .downcall = gss_pipe_downcall,
> .destroy_msg = gss_pipe_destroy_msg,
> - .open_pipe = gss_pipe_open_v1,
> .release_pipe = gss_pipe_release,
> };
>
> @@ -2226,7 +2076,6 @@ static int __init init_rpcsec_gss(void)
> err = register_pernet_subsys(&rpcsec_gss_net_ops);
> if (err)
> goto out_svc_exit;
> - rpc_init_wait_queue(&pipe_version_rpc_waitqueue, "gss pipe version");
> return 0;
> out_svc_exit:
> gss_svc_shutdown();
> diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
> index 3ecc194c21ef..633a66bc5df9 100644
> --- a/net/sunrpc/rpc_pipe.c
> +++ b/net/sunrpc/rpc_pipe.c
> @@ -213,19 +213,12 @@ static int
> rpc_pipe_open(struct inode *inode, struct file *filp)
> {
> struct rpc_pipe *pipe;
> - int first_open;
> int res = -ENXIO;
>
> inode_lock(inode);
> pipe = RPC_I(inode)->pipe;
> if (pipe == NULL)
> goto out;
> - first_open = pipe->nreaders == 0 && pipe->nwriters == 0;
> - if (first_open && pipe->ops->open_pipe) {
> - res = pipe->ops->open_pipe(inode);
> - if (res)
> - goto out;
> - }
> if (filp->f_mode & FMODE_READ)
> pipe->nreaders++;
> if (filp->f_mode & FMODE_WRITE)
> --
> 2.33.1
