Commit d09e860c authored by Steve French's avatar Steve French
Browse files

[CIFS] Adds to dns_resolver checking if the server name is an IP addr and... 


[CIFS] Adds to dns_resolver checking if the server name is an IP addr and skipping upcall in this case.

Signed-off-by: default avatarIgor Mammedov <niallain@gmail.com>
Signed-off-by: default avatar <sfrench@us.ibm.com>
parent 404e86e1

fs/cifs/dns_resolve.c

+52 −10
Original line number Diff line number Diff line
@@ -55,6 +55,32 @@ struct key_type key_type_dns_resolver = { 
	.match       = user_match,

};



/* Checks if supplied name is IP address

 * returns:

 * 		1 - name is IP

 * 		0 - name is not IP

 */

static int is_ip(const char *name)

{

	int rc;

	struct sockaddr_in sin_server;

	struct sockaddr_in6 sin_server6;



	rc = cifs_inet_pton(AF_INET, name,

			&sin_server.sin_addr.s_addr);



	if (rc <= 0) {

		/* not ipv4 address, try ipv6 */

		rc = cifs_inet_pton(AF_INET6, name,

				&sin_server6.sin6_addr.in6_u);

		if (rc > 0)

			return 1;

	} else {

		return 1;

	}

	/* we failed translating address */

	return 0;

}



/* Resolves server name to ip address.

 * input:
@@ -67,8 +93,9 @@ int 
dns_resolve_server_name_to_ip(const char *unc, char **ip_addr)

{

	int rc = -EAGAIN;

	struct key *rkey;

	struct key *rkey = ERR_PTR(-EAGAIN);

	char *name;

	char *data = NULL;

	int len;



	if (!ip_addr || !unc)
@@ -97,26 +124,41 @@ dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) 
	memcpy(name, unc+2, len);

	name[len] = 0;



	if (is_ip(name)) {

		cFYI(1, ("%s: it is IP, skipping dns upcall: %s",

					__func__, name));

		data = name;

		goto skip_upcall;

	}



	rkey = request_key(&key_type_dns_resolver, name, "");

	if (!IS_ERR(rkey)) {

		len = strlen(rkey->payload.data);

		*ip_addr = kmalloc(len+1, GFP_KERNEL);

		if (*ip_addr) {

			memcpy(*ip_addr, rkey->payload.data, len);

			(*ip_addr)[len] = '\0';

		data = rkey->payload.data;

		cFYI(1, ("%s: resolved: %s to %s", __func__,

					rkey->description,

					*ip_addr

				));

	} else {

		cERROR(1, ("%s: unable to resolve: %s", __func__, name));

		goto out;

	}



skip_upcall:

	if (data) {

		len = strlen(data);

		*ip_addr = kmalloc(len+1, GFP_KERNEL);

		if (*ip_addr) {

			memcpy(*ip_addr, data, len);

			(*ip_addr)[len] = '\0';

			rc = 0;

		} else {

			rc = -ENOMEM;

		}

		if (!IS_ERR(rkey))

			key_put(rkey);

	} else {

		cERROR(1, ("%s: unable to resolve: %s", __func__, name));

	}



out:

	kfree(name);

	return rc;

}