APPLIED: [SRU HWE-5.8] NFSv4: Initialise connection to the server in nfs4_alloc_client()

[Stefan Bader]

On 28.09.21 01:12, Thadeu Lima de Souza Cascardo wrote:
> From: Trond Myklebust <trond.myklebust at hammerspace.com>
> 
> Set up the connection to the NFSv4 server in nfs4_alloc_client(), before
> we've added the struct nfs_client to the net-namespace's nfs_client_list
> so that a downed server won't cause other mounts to hang in the trunking
> detection code.
> 
> Reported-by: Michael Wakabayashi <mwakabayashi at vmware.com>
> Fixes: 5c6e5b60aae4 ("NFS: Fix an Oops in the pNFS files and flexfiles connection setup to the DS")
> Signed-off-by: Trond Myklebust <trond.myklebust at hammerspace.com>
> (cherry picked from commit dd99e9f98fbf423ff6d365b37a98e8879170f17c)
> CVE-2021-38199
> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
> ---

Applied to focal:linux-hwe-5.8/hwe-5.8. Thanks.

-Stefan

>   fs/nfs/nfs4client.c | 82 +++++++++++++++++++++++----------------------
>   1 file changed, 42 insertions(+), 40 deletions(-)
> 
> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
> index 13157bfd9414..8b354c15ae0d 100644
> --- a/fs/nfs/nfs4client.c
> +++ b/fs/nfs/nfs4client.c
> @@ -197,8 +197,11 @@ void nfs40_shutdown_client(struct nfs_client *clp)
>   
>   struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
>   {
> -	int err;
> +	char buf[INET6_ADDRSTRLEN + 1];
> +	const char *ip_addr = cl_init->ip_addr;
>   	struct nfs_client *clp = nfs_alloc_client(cl_init);
> +	int err;
> +
>   	if (IS_ERR(clp))
>   		return clp;
>   
> @@ -222,6 +225,44 @@ struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
>   	init_waitqueue_head(&clp->cl_lock_waitq);
>   #endif
>   	INIT_LIST_HEAD(&clp->pending_cb_stateids);
> +
> +	if (cl_init->minorversion != 0)
> +		__set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
> +	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
> +	__set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);
> +
> +	/*
> +	 * Set up the connection to the server before we add add to the
> +	 * global list.
> +	 */
> +	err = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_GSS_KRB5I);
> +	if (err == -EINVAL)
> +		err = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
> +	if (err < 0)
> +		goto error;
> +
> +	/* If no clientaddr= option was specified, find a usable cb address */
> +	if (ip_addr == NULL) {
> +		struct sockaddr_storage cb_addr;
> +		struct sockaddr *sap = (struct sockaddr *)&cb_addr;
> +
> +		err = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
> +		if (err < 0)
> +			goto error;
> +		err = rpc_ntop(sap, buf, sizeof(buf));
> +		if (err < 0)
> +			goto error;
> +		ip_addr = (const char *)buf;
> +	}
> +	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
> +
> +	err = nfs_idmap_new(clp);
> +	if (err < 0) {
> +		dprintk("%s: failed to create idmapper. Error = %d\n",
> +			__func__, err);
> +		goto error;
> +	}
> +	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);
>   	return clp;
>   
>   error:
> @@ -372,8 +413,6 @@ static int nfs4_init_client_minor_version(struct nfs_client *clp)
>   struct nfs_client *nfs4_init_client(struct nfs_client *clp,
>   				    const struct nfs_client_initdata *cl_init)
>   {
> -	char buf[INET6_ADDRSTRLEN + 1];
> -	const char *ip_addr = cl_init->ip_addr;
>   	struct nfs_client *old;
>   	int error;
>   
> @@ -381,43 +420,6 @@ struct nfs_client *nfs4_init_client(struct nfs_client *clp,
>   		/* the client is initialised already */
>   		return clp;
>   
> -	/* Check NFS protocol revision and initialize RPC op vector */
> -	clp->rpc_ops = &nfs_v4_clientops;
> -
> -	if (clp->cl_minorversion != 0)
> -		__set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
> -	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
> -	__set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);
> -
> -	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_GSS_KRB5I);
> -	if (error == -EINVAL)
> -		error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
> -	if (error < 0)
> -		goto error;
> -
> -	/* If no clientaddr= option was specified, find a usable cb address */
> -	if (ip_addr == NULL) {
> -		struct sockaddr_storage cb_addr;
> -		struct sockaddr *sap = (struct sockaddr *)&cb_addr;
> -
> -		error = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
> -		if (error < 0)
> -			goto error;
> -		error = rpc_ntop(sap, buf, sizeof(buf));
> -		if (error < 0)
> -			goto error;
> -		ip_addr = (const char *)buf;
> -	}
> -	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
> -
> -	error = nfs_idmap_new(clp);
> -	if (error < 0) {
> -		dprintk("%s: failed to create idmapper. Error = %d\n",
> -			__func__, error);
> -		goto error;
> -	}
> -	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);
> -
>   	error = nfs4_init_client_minor_version(clp);
>   	if (error < 0)
>   		goto error;
> 


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