On Thu, 2014-06-12 at 15:02 -0400, andros@xxxxxxxxxx wrote:
> From: Andy Adamson <andros@xxxxxxxxxx>
>
> Fix nfs4_negotiate_security to create an rpc_clnt used to test each SECINFO
> returned pseudoflavor. Check credential creation (and gss_context creation)
> which is important for RPC_AUTH_GSS pseudoflavors which can fail for multiple
> reasons including mis-configuration.
>
> Don't call nfs4_negotiate in nfs4_submount as it was just called by
> nfs4_proc_lookup_mountpoint (nfs4_proc_lookup_common)
>
> Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
>
> Conflicts:
> fs/nfs/nfs4namespace.c
Queued for 3.17, but I had to fix a couple of issues with
nfs_find_best_sec() first. See below:
> ---
> fs/nfs/nfs4_fs.h | 2 +-
> fs/nfs/nfs4namespace.c | 103 ++++++++++++++++++++++++++++---------------------
> fs/nfs/nfs4proc.c | 2 +-
> net/sunrpc/auth.c | 1 +
> 4 files changed, 61 insertions(+), 47 deletions(-)
>
> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
> index f63cb87..ba2affa 100644
> --- a/fs/nfs/nfs4_fs.h
> +++ b/fs/nfs/nfs4_fs.h
> @@ -230,7 +230,7 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
> extern struct file_system_type nfs4_fs_type;
>
> /* nfs4namespace.c */
> -struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
> +struct rpc_clnt *nfs4_negotiate_security(struct rpc_clnt *, struct inode *, struct qstr *);
> struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
> struct nfs_fh *, struct nfs_fattr *);
> int nfs4_replace_transport(struct nfs_server *server,
> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
> index 3d5dbf8..5517f02 100644
> --- a/fs/nfs/nfs4namespace.c
> +++ b/fs/nfs/nfs4namespace.c
> @@ -139,19 +139,28 @@ static size_t nfs_parse_server_name(char *string, size_t len,
> * @server: NFS server struct
> * @flavors: List of security tuples returned by SECINFO procedure
> *
> - * Return the pseudoflavor of the first security mechanism in
> - * "flavors" that is locally supported. Return RPC_AUTH_UNIX if
> - * no matching flavor is found in the array. The "flavors" array
> + * Return an rpc client that uses the first security mechanism in
> + * "flavors" that is locally supported. The "flavors" array
> * is searched in the order returned from the server, per RFC 3530
> - * recommendation.
> + * recommendation and each flavor is checked for membership in the
> + * sec= mount option list if it exists.
> + *
> + * Return -EPERM if no matching flavor is found in the array.
> + *
> + * Please call rpc_shutdown_client() when you are done with this rpc client.
> + *
> */
> -static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
> +static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
> + struct nfs_server *server,
> struct nfs4_secinfo_flavors *flavors)
> {
> - rpc_authflavor_t pseudoflavor;
> + rpc_authflavor_t pflavor;
> struct nfs4_secinfo4 *secinfo;
> + struct rpc_clnt *new;
> unsigned int i;
> + struct rpc_cred *cred;
>
> + new = ERR_PTR(-EPERM);
> for (i = 0; i < flavors->num_flavors; i++) {
> secinfo = &flavors->flavors[i];
>
> @@ -159,62 +168,71 @@ static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
> case RPC_AUTH_NULL:
> case RPC_AUTH_UNIX:
> case RPC_AUTH_GSS:
> - pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
> + pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
> &secinfo->flavor_info);
> - /* make sure pseudoflavor matches sec= mount opt */
> - if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
> - nfs_auth_info_match(&server->auth_info,
> - pseudoflavor))
> - return pseudoflavor;
> - break;
> + /* does the pseudoflavor match a sec= mount opt? */
> + if (pflavor != RPC_AUTH_MAXFLAVOR &&
> + nfs_auth_info_match(&server->auth_info, pflavor)) {
> +
> + /* Cloning creates an rpc_auth for the flavor */
> + new = rpc_clone_client_set_auth(clnt, pflavor);
> + if (IS_ERR(new))
> + continue;
If IS_ERR(new), we can end up returning an error which is not EPERM.
> + /**
> + * Check that the user actually can use the
> + * flavor. This is mostly for RPC_AUTH_GSS
> + * where cr_init obtains a gss context
> + */
> + cred = rpcauth_lookupcred(new->cl_auth, 0);
> + if (IS_ERR(cred)) {
> + rpc_shutdown_client(new);
> + continue;
> + }
> + put_rpccred(cred);
> + break;
If IS_ERR(cred), we can end up freeing 'new', and then returning the
pointer to the freed client.
> + }
> }
> }
> -
> - /* if there were any sec= options then nothing matched */
> - if (server->auth_info.flavor_len > 0)
> - return -EPERM;
> -
> - return RPC_AUTH_UNIX;
> + return new;
> }
>
> -static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name)
> +/**
> + * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
> + * return an rpc_clnt that uses the best available security flavor with
> + * respect to the secinfo flavor list and the sec= mount options.
> + *
> + * @clnt: RPC client to clone
> + * @inode: directory inode
> + * @name: lookup name
> + *
> + * Please call rpc_shutdown_client() when you are done with this rpc client.
> + */
> +struct rpc_clnt *
> +nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
> + struct qstr *name)
> {
> struct page *page;
> struct nfs4_secinfo_flavors *flavors;
> - rpc_authflavor_t flavor;
> + struct rpc_clnt *new = ERR_PTR(-ENOMEM);
> int err;
>
> page = alloc_page(GFP_KERNEL);
> if (!page)
> - return -ENOMEM;
> + return new;
> +
> flavors = page_address(page);
>
> err = nfs4_proc_secinfo(inode, name, flavors);
> if (err < 0) {
> - flavor = err;
> + new = ERR_PTR(err);;
> goto out;
> }
>
> - flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
> + new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
>
> out:
> put_page(page);
> - return flavor;
> -}
> -
> -/*
> - * Please call rpc_shutdown_client() when you are done with this client.
> - */
> -struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode,
> - struct qstr *name)
> -{
> - rpc_authflavor_t flavor;
> -
> - flavor = nfs4_negotiate_security(inode, name);
> - if ((int)flavor < 0)
> - return ERR_PTR((int)flavor);
> -
> - return rpc_clone_client_set_auth(clnt, flavor);
> + return new;
> }
>
> static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
> @@ -397,11 +415,6 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
>
> if (client->cl_auth->au_flavor != flavor)
> flavor = client->cl_auth->au_flavor;
> - else {
> - rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
> - if ((int)new >= 0)
> - flavor = new;
> - }
> mnt = nfs_do_submount(dentry, fh, fattr, flavor);
> out:
> rpc_shutdown_client(client);
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 68dd81e..fe14063 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -3247,7 +3247,7 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
> err = -EPERM;
> if (client != *clnt)
> goto out;
> - client = nfs4_create_sec_client(client, dir, name);
> + client = nfs4_negotiate_security(client, dir, name);
> if (IS_ERR(client))
> return PTR_ERR(client);
>
> diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
> index 5285ead..1d97e19 100644
> --- a/net/sunrpc/auth.c
> +++ b/net/sunrpc/auth.c
> @@ -592,6 +592,7 @@ rpcauth_lookupcred(struct rpc_auth *auth, int flags)
> put_group_info(acred.group_info);
> return ret;
> }
> +EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
>
> void
> rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
--
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@xxxxxxxxxxxxxxx
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