From d46d494214cabfd03eb836e3a8ff3768d4c51497 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 18 Jul 2014 18:56:36 +0100 Subject: [PATCH] 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: David Howells Acked-by: Steve Dickson Acked-by: Jeff Layton --- net/dns_resolver/dns_key.c | 43 ++++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 18 deletions(-) diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c index bf8584339048..f380b2c58178 100644 --- a/net/dns_resolver/dns_key.c +++ b/net/dns_resolver/dns_key.c @@ -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 "[:]" * @@ -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, -- 2.20.1