1 files changed, 51 insertions, 23 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index b2afe9556147..c20322636a68 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4957,25 +4957,54 @@ static void nfs4_init_boot_verifier(const struct nfs_client *clp,
 	memcpy(bootverf->data, verf, sizeof(bootverf->data));
 }
 
-static unsigned int
-nfs4_init_nonuniform_client_string(struct nfs_client *clp,
-				   char *buf, size_t len)
+static int
+nfs4_init_nonuniform_client_string(struct nfs_client *clp)
 {
-	unsigned int result;
+	int result;
+	size_t len;
+	char *str;
+	bool retried = false;
 
 	if (clp->cl_owner_id != NULL)
-		return strlcpy(buf, clp->cl_owner_id, len);
+		return 0;
+retry:
+	rcu_read_lock();
+	len = 10 + strlen(clp->cl_ipaddr) + 1 +
+		strlen(rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR)) +
+		1 +
+		strlen(rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_PROTO)) +
+		1;
+	rcu_read_unlock();
+
+	if (len > NFS4_OPAQUE_LIMIT + 1)
+		return -EINVAL;
+
+	/*
+	 * Since this string is allocated at mount time, and held until the
+	 * nfs_client is destroyed, we can use GFP_KERNEL here w/o worrying
+	 * about a memory-reclaim deadlock.
+	 */
+	str = kmalloc(len, GFP_KERNEL);
+	if (!str)
+		return -ENOMEM;
 
 	rcu_read_lock();
-	result = scnprintf(buf, len, "Linux NFSv4.0 %s/%s %s",
-				clp->cl_ipaddr,
-				rpc_peeraddr2str(clp->cl_rpcclient,
-							RPC_DISPLAY_ADDR),
-				rpc_peeraddr2str(clp->cl_rpcclient,
-							RPC_DISPLAY_PROTO));
+	result = scnprintf(str, len, "Linux NFSv4.0 %s/%s %s",
+			clp->cl_ipaddr,
+			rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR),
+			rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_PROTO));
 	rcu_read_unlock();
-	clp->cl_owner_id = kstrdup(buf, GFP_KERNEL);
-	return result;
+
+	/* Did something change? */
+	if (result >= len) {
+		kfree(str);
+		if (retried)
+			return -EINVAL;
+		retried = true;
+		goto retry;
+	}
+	clp->cl_owner_id = str;
+	return 0;
 }
 
 static unsigned int
@@ -5066,20 +5095,19 @@ int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
 
 	/* nfs_client_id4 */
 	nfs4_init_boot_verifier(clp, &sc_verifier);
-	if (test_bit(NFS_CS_MIGRATION, &clp->cl_flags))
+	if (test_bit(NFS_CS_MIGRATION, &clp->cl_flags)) {
 		setclientid.sc_name_len =
 				nfs4_init_uniform_client_string(clp,
 						setclientid.sc_name,
 						sizeof(setclientid.sc_name));
-	else
-		setclientid.sc_name_len =
-				nfs4_init_nonuniform_client_string(clp,
-						setclientid.sc_name,
-						sizeof(setclientid.sc_name));
-
-	if (!clp->cl_owner_id) {
-		status = -ENOMEM;
-		goto out;
+		if (!clp->cl_owner_id) {
+			status = -ENOMEM;
+			goto out;
+		}
+	} else {
+		status = nfs4_init_nonuniform_client_string(clp);
+		if (status)
+			goto out;
 	}
 
 	/* cb_client4 */