keys, dns: Fix missing size check of V1 server-list header

[linux-2.6-block.git] / net / dns_resolver / dns_key.c

diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
index 2a6d363763a2bcf287708db50c9fba89486071e0..f18ca02aa95a61d3b16da500aa1df5362806de3a 100644 (file)
--- a/net/dns_resolver/dns_key.c
+++ b/net/dns_resolver/dns_key.c
@@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;
 static int
 dns_resolver_preparse(struct key_preparsed_payload *prep)
 {
-       const struct dns_server_list_v1_header *v1;
-       const struct dns_payload_header *bin;
        struct user_key_payload *upayload;
        unsigned long derrno;
        int ret;
@@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)
                return -EINVAL;
 
        if (data[0] == 0) {
+               const struct dns_server_list_v1_header *v1;
+
                /* It may be a server list. */
-               if (datalen <= sizeof(*bin))
+               if (datalen <= sizeof(*v1))
                        return -EINVAL;
 
-               bin = (const struct dns_payload_header *)data;
-               kenter("[%u,%u],%u", bin->content, bin->version, datalen);
-               if (bin->content != DNS_PAYLOAD_IS_SERVER_LIST) {
+               v1 = (const struct dns_server_list_v1_header *)data;
+               kenter("[%u,%u],%u", v1->hdr.content, v1->hdr.version, datalen);
+               if (v1->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST) {
                        pr_warn_ratelimited(
                                "dns_resolver: Unsupported content type (%u)\n",
-                               bin->content);
+                               v1->hdr.content);
                        return -EINVAL;
                }
 
-               if (bin->version != 1) {
+               if (v1->hdr.version != 1) {
                        pr_warn_ratelimited(
                                "dns_resolver: Unsupported server list version (%u)\n",
-                               bin->version);
+                               v1->hdr.version);
                        return -EINVAL;
                }
 
-               v1 = (const struct dns_server_list_v1_header *)bin;
                if ((v1->status != DNS_LOOKUP_GOOD &&
                     v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) {
                        if (prep->expiry == TIME64_MAX)