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Commit d46d4942 authored by David Howells's avatar David Howells
Browse files

KEYS: DNS: Use key preparsing 



Make use of key preparsing in the DNS resolver so that quota size determination
can take place prior to keyring locking when a key is being added.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarSteve Dickson <steved@redhat.com>
Acked-by: default avatarJeff Layton <jlayton@primarydata.com>
parent 7c3bec0a

net/dns_resolver/dns_key.c

+25 −18
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ const struct cred *dns_resolver_cache; 
#define	DNS_ERRORNO_OPTION	"dnserror"



/*

 * Instantiate a user defined key for dns_resolver.

 * Preparse instantiation data for a dns_resolver key.

 *

 * The data must be a NUL-terminated string, with the NUL char accounted in

 * datalen.
@@ -58,17 +58,15 @@ const struct cred *dns_resolver_cache; 
 *        "ip1,ip2,...#foo=bar"

 */

static int

dns_resolver_instantiate(struct key *key, struct key_preparsed_payload *prep)

dns_resolver_preparse(struct key_preparsed_payload *prep)

{

	struct user_key_payload *upayload;

	unsigned long derrno;

	int ret;

	size_t datalen = prep->datalen, result_len = 0;

	int datalen = prep->datalen, result_len = 0;

	const char *data = prep->data, *end, *opt;



	kenter("%%%d,%s,'%*.*s',%zu",

	       key->serial, key->description,

	       (int)datalen, (int)datalen, data, datalen);

	kenter("'%*.*s',%u", datalen, datalen, data, datalen);



	if (datalen <= 1 || !data || data[datalen - 1] != '\0')

		return -EINVAL;
@@ -95,8 +93,7 @@ dns_resolver_instantiate(struct key *key, struct key_preparsed_payload *prep) 
			opt_len = next_opt - opt;

			if (!opt_len) {

				printk(KERN_WARNING

				       "Empty option to dns_resolver key %d\n",

				       key->serial);

				       "Empty option to dns_resolver key\n");

				return -EINVAL;

			}
@@ -125,30 +122,28 @@ dns_resolver_instantiate(struct key *key, struct key_preparsed_payload *prep) 
					goto bad_option_value;



				kdebug("dns error no. = %lu", derrno);

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

				prep->type_data[0] = ERR_PTR(-derrno);

				continue;

			}



		bad_option_value:

			printk(KERN_WARNING

			       "Option '%*.*s' to dns_resolver key %d:"

			       "Option '%*.*s' to dns_resolver key:"

			       " bad/missing value\n",

			       opt_nlen, opt_nlen, opt, key->serial);

			       opt_nlen, opt_nlen, opt);

			return -EINVAL;

		} while (opt = next_opt + 1, opt < end);

	}



	/* don't cache the result if we're caching an error saying there's no

	 * result */

	if (key->type_data.x[0]) {

		kleave(" = 0 [h_error %ld]", key->type_data.x[0]);

	if (prep->type_data[0]) {

		kleave(" = 0 [h_error %ld]", PTR_ERR(prep->type_data[0]));

		return 0;

	}



	kdebug("store result");

	ret = key_payload_reserve(key, result_len);

	if (ret < 0)

		return -EINVAL;

	prep->quotalen = result_len;



	upayload = kmalloc(sizeof(*upayload) + result_len + 1, GFP_KERNEL);

	if (!upayload) {
@@ -159,12 +154,22 @@ dns_resolver_instantiate(struct key *key, struct key_preparsed_payload *prep) 
	upayload->datalen = result_len;

	memcpy(upayload->data, data, result_len);

	upayload->data[result_len] = '\0';

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



	prep->payload[0] = upayload;

	kleave(" = 0");

	return 0;

}



/*

 * Clean up the preparse data

 */

static void dns_resolver_free_preparse(struct key_preparsed_payload *prep)

{

	pr_devel("==>%s()\n", __func__);



	kfree(prep->payload[0]);

}



/*

 * The description is of the form "[<type>:]<domain_name>"

 *
@@ -234,7 +239,9 @@ static long dns_resolver_read(const struct key *key, 


struct key_type key_type_dns_resolver = {

	.name		= "dns_resolver",

	.instantiate	= dns_resolver_instantiate,

	.preparse	= dns_resolver_preparse,

	.free_preparse	= dns_resolver_free_preparse,

	.instantiate	= generic_key_instantiate,

	.match		= dns_resolver_match,

	.revoke		= user_revoke,

	.destroy	= user_destroy,