NFS: Add string length argument to nfs_parse_server_address

To make nfs_parse_server_address() more generally useful, allow it to
accept input strings that are not terminated with '\0'.

Signed-off-by: Chuck Lever <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/super.c

···
 	return 0;
 }
 
-/*
- * Parse string addresses passed in via a mount option,
- * and construct a sockaddr based on the result.
- *
- * If address parsing fails, set the sockaddr's address
- * family to AF_UNSPEC to force nfs_verify_server_address()
- * to punt the mount.
- */
-static void nfs_parse_server_address(char *value,
-				     struct sockaddr *sap,
-				     size_t *len)
+static void nfs_parse_ipv4_address(char *string, size_t str_len,
+				   struct sockaddr *sap, size_t *addr_len)
 {
-	if (strchr(value, ':')) {
-		struct sockaddr_in6 *ap = (struct sockaddr_in6 *)sap;
-		u8 *addr = (u8 *)&ap->sin6_addr.in6_u;
+	struct sockaddr_in *sin = (struct sockaddr_in *)sap;
+	u8 *addr = (u8 *)&sin->sin_addr.s_addr;
 
-		ap->sin6_family = AF_INET6;
-		*len = sizeof(*ap);
-		if (in6_pton(value, -1, addr, '\0', NULL))
-			return;
-	} else {
-		struct sockaddr_in *ap = (struct sockaddr_in *)sap;
-		u8 *addr = (u8 *)&ap->sin_addr.s_addr;
+	if (str_len <= INET_ADDRSTRLEN) {
+		dfprintk(MOUNT, "NFS: parsing IPv4 address %*s\n",
+				(int)str_len, string);
 
-		ap->sin_family = AF_INET;
-		*len = sizeof(*ap);
-		if (in4_pton(value, -1, addr, '\0', NULL))
+		sin->sin_family = AF_INET;
+		*addr_len = sizeof(*sin);
+		if (in4_pton(string, str_len, addr, '\0', NULL))
 			return;
 	}
 
 	sap->sa_family = AF_UNSPEC;
-	*len = 0;
+	*addr_len = 0;
+}
+
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+static void nfs_parse_ipv6_address(char *string, size_t str_len,
+				   struct sockaddr *sap, size_t *addr_len)
+{
+	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
+	u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
+
+	if (str_len <= INET6_ADDRSTRLEN) {
+		dfprintk(MOUNT, "NFS: parsing IPv6 address %*s\n",
+				(int)str_len, string);
+
+		sin6->sin6_family = AF_INET6;
+		*addr_len = sizeof(*sin6);
+		if (in6_pton(string, str_len, addr, '\0', NULL))
+			return;
+	}
+
+	sap->sa_family = AF_UNSPEC;
+	*addr_len = 0;
+}
+#else
+static void nfs_parse_ipv6_address(char *string, size_t str_len,
+				   struct sockaddr *sap, size_t *addr_len)
+{
+	sap->sa_family = AF_UNSPEC;
+	*addr_len = 0;
+}
+#endif
+
+/*
+ * Construct a sockaddr based on the contents of a string that contains
+ * an IP address in presentation format.
+ *
+ * If there is a problem constructing the new sockaddr, set the address
+ * family to AF_UNSPEC.
+ */
+static void nfs_parse_ip_address(char *string, size_t str_len,
+				 struct sockaddr *sap, size_t *addr_len)
+{
+	unsigned int i, colons;
+
+	colons = 0;
+	for (i = 0; i < str_len; i++)
+		if (string[i] == ':')
+			colons++;
+
+	if (colons >= 2)
+		nfs_parse_ipv6_address(string, str_len, sap, addr_len);
+	else
+		nfs_parse_ipv4_address(string, str_len, sap, addr_len);
 }
 
 /*
···
 			string = match_strdup(args);
 			if (string == NULL)
 				goto out_nomem;
-			nfs_parse_server_address(string, (struct sockaddr *)
-						 &mnt->nfs_server.address,
-						 &mnt->nfs_server.addrlen);
+			nfs_parse_ip_address(string, strlen(string),
+					     (struct sockaddr *)
+						&mnt->nfs_server.address,
+					     &mnt->nfs_server.addrlen);
 			kfree(string);
 			break;
 		case Opt_clientaddr:
···
 			string = match_strdup(args);
 			if (string == NULL)
 				goto out_nomem;
-			nfs_parse_server_address(string, (struct sockaddr *)
-						 &mnt->mount_server.address,
-						 &mnt->mount_server.addrlen);
+			nfs_parse_ip_address(string, strlen(string),
+					     (struct sockaddr *)
+						&mnt->mount_server.address,
+					     &mnt->mount_server.addrlen);
 			kfree(string);
 			break;
 

include/linux/inet.h

···
 
 #include <linux/types.h>
 
+/*
+ * These mimic similar macros defined in user-space for inet_ntop(3).
+ * See /usr/include/netinet/in.h .
+ */
+#define INET_ADDRSTRLEN		(16)
+#define INET6_ADDRSTRLEN	(48)
+
 extern __be32 in_aton(const char *str);
 extern int in4_pton(const char *src, int srclen, u8 *dst, int delim, const char **end);
 extern int in6_pton(const char *src, int srclen, u8 *dst, int delim, const char **end);