wifi: cfg80211: Deduplicate certificate loading

load_keys_from_buffer() in net/wireless/reg.c duplicates
x509_load_certificate_list() in crypto/asymmetric_keys/x509_loader.c
for no apparent reason.

Deduplicate it.  No functional change intended.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/e7280be84acda02634bc7cb52c97656182b9c700.1673197326.git.lukas@wunner.deSigned-off-by: Johannes Berg <johannes.berg@intel.com>

crypto/asymmetric_keys/x509_loader.c

@@ -55,3 +55,4 @@ int x509_load_certificate_list(const u8 cert_list[],
 	pr_err("Problem parsing in-kernel X.509 certificate list\n");
 	return 0;
 }
+EXPORT_SYMBOL_GPL(x509_load_certificate_list);

net/wireless/reg.c

@@ -737,51 +737,9 @@ static bool valid_country(const u8 *data, unsigned int size,
 }
 
 #ifdef CONFIG_CFG80211_REQUIRE_SIGNED_REGDB
-static struct key *builtin_regdb_keys;
-
-static void __init load_keys_from_buffer(const u8 *p, unsigned int buflen)
-{
-	const u8 *end = p + buflen;
-	size_t plen;
-	key_ref_t key;
-
-	while (p < end) {
-		/* Each cert begins with an ASN.1 SEQUENCE tag and must be more
-		 * than 256 bytes in size.
-		 */
-		if (end - p < 4)
-			goto dodgy_cert;
-		if (p[0] != 0x30 &&
-		    p[1] != 0x82)
-			goto dodgy_cert;
-		plen = (p[2] << 8) | p[3];
-		plen += 4;
-		if (plen > end - p)
-			goto dodgy_cert;
-
-		key = key_create_or_update(make_key_ref(builtin_regdb_keys, 1),
-					   "asymmetric", NULL, p, plen,
-					   ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
-					    KEY_USR_VIEW | KEY_USR_READ),
-					   KEY_ALLOC_NOT_IN_QUOTA |
-					   KEY_ALLOC_BUILT_IN |
-					   KEY_ALLOC_BYPASS_RESTRICTION);
-		if (IS_ERR(key)) {
-			pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
-			       PTR_ERR(key));
-		} else {
-			pr_notice("Loaded X.509 cert '%s'\n",
-				  key_ref_to_ptr(key)->description);
-			key_ref_put(key);
-		}
-		p += plen;
-	}
-
-	return;
+#include <keys/asymmetric-type.h>
 
-dodgy_cert:
-	pr_err("Problem parsing in-kernel X.509 certificate list\n");
-}
+static struct key *builtin_regdb_keys;
 
 static int __init load_builtin_regdb_keys(void)
 {
@@ -797,11 +755,15 @@ static int __init load_builtin_regdb_keys(void)
 	pr_notice("Loading compiled-in X.509 certificates for regulatory database\n");
 
 #ifdef CONFIG_CFG80211_USE_KERNEL_REGDB_KEYS
-	load_keys_from_buffer(shipped_regdb_certs, shipped_regdb_certs_len);
+	x509_load_certificate_list(shipped_regdb_certs,
+				   shipped_regdb_certs_len,
+				   builtin_regdb_keys);
 #endif
 #ifdef CONFIG_CFG80211_EXTRA_REGDB_KEYDIR
 	if (CONFIG_CFG80211_EXTRA_REGDB_KEYDIR[0] != '\0')
-		load_keys_from_buffer(extra_regdb_certs, extra_regdb_certs_len);
+		x509_load_certificate_list(extra_regdb_certs,
+					   extra_regdb_certs_len,
+					   builtin_regdb_keys);
 #endif
 
 	return 0;