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[CIFS] clean up upcall handling for dns_resolver keys

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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: Jeff Layton <jlayton@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Steve French 2008-09-23 18:46:07 +00:00
parent ee2fd967fb
commit 9d81523480
1 changed files with 46 additions and 38 deletions
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84
fs/cifs/dns_resolve.c
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@ -29,45 +29,13 @@
#include "cifsproto.h"
#include "cifs_debug.h"
static int dns_resolver_instantiate(struct key *key, const void *data,
size_t datalen)
{
int rc = 0;
char *ip;
ip = kmalloc(datalen+1, GFP_KERNEL);
if (!ip)
return -ENOMEM;
memcpy(ip, data, datalen);
ip[datalen] = '\0';
rcu_assign_pointer(key->payload.data, ip);
return rc;
}
static void
dns_resolver_destroy(struct key *key)
{
kfree(key->payload.data);
}
struct key_type key_type_dns_resolver = {
.name = "dns_resolver",
.def_datalen = sizeof(struct in_addr),
.describe = user_describe,
.instantiate = dns_resolver_instantiate,
.destroy = dns_resolver_destroy,
.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)
static int
is_ip(const char *name)
{
int rc;
struct sockaddr_in sin_server;
@ -89,6 +57,47 @@ static int is_ip(const char *name)
return 0;
}
static int
dns_resolver_instantiate(struct key *key, const void *data,
size_t datalen)
{
int rc = 0;
char *ip;
ip = kmalloc(datalen + 1, GFP_KERNEL);
if (!ip)
return -ENOMEM;
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;
}
static void
dns_resolver_destroy(struct key *key)
{
kfree(key->payload.data);
}
struct key_type key_type_dns_resolver = {
.name = "dns_resolver",
.def_datalen = sizeof(struct in_addr),
.describe = user_describe,
.instantiate = dns_resolver_instantiate,
.destroy = dns_resolver_destroy,
.match = user_match,
};
/* 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);
*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,