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Commit 9d815234 authored by Steve French's avatar Steve French
Browse files

[CIFS] clean up upcall handling for dns_resolver keys 



We're given the datalen in the downcall, so there's no need to do any
calls to strlen(). Just keep track of the datalen in the key. Finally,
add a sanity check of the data in the downcall to make sure that it
looks like a real IP address.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Acked-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent ee2fd967

fs/cifs/dns_resolve.c

+41 −33
Original line number Diff line number Diff line
@@ -29,7 +29,36 @@ 
#include "cifsproto.h"

#include "cifs_debug.h"



static int dns_resolver_instantiate(struct key *key, const void *data,

/* 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;

}



static int

dns_resolver_instantiate(struct key *key, const void *data,

		size_t datalen)

{

	int rc = 0;
@@ -42,6 +71,13 @@ static int dns_resolver_instantiate(struct key *key, const void *data, 
	memcpy(ip, data, datalen);

	ip[datalen] = '\0';



	/* make sure this looks like an address */

	if (!is_ip((const char *) ip)) {

		kfree(ip);

		return -EINVAL;

	}



	key->type_data.x[0] = datalen;

	rcu_assign_pointer(key->payload.data, ip);



	return rc;
@@ -62,33 +98,6 @@ 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:

 * 	unc - server UNC
@@ -140,6 +149,7 @@ dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) 


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

	if (!IS_ERR(rkey)) {

		len = rkey->type_data.x[0];

		data = rkey->payload.data;

	} else {

		cERROR(1, ("%s: unable to resolve: %s", __func__, name));
@@ -148,11 +158,9 @@ dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) 


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';

			memcpy(*ip_addr, data, len + 1);

			if (!IS_ERR(rkey))

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

							name,