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KEYS: DNS: Use key preparsing

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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: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
This commit is contained in:
David Howells 2014-07-18 18:56:36 +01:00
parent 7c3bec0a1f
commit d46d494214
1 changed files with 25 additions and 18 deletions
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43
net/dns_resolver/dns_key.c
View file

@ -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,