1 /* Signature verification with an asymmetric key 2 * 3 * See Documentation/security/asymmetric-keys.txt 4 * 5 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. 6 * Written by David Howells (dhowells@redhat.com) 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public Licence 10 * as published by the Free Software Foundation; either version 11 * 2 of the Licence, or (at your option) any later version. 12 */ 13 14 #include <keys/asymmetric-subtype.h> 15 #include <linux/module.h> 16 #include <linux/err.h> 17 #include <crypto/public_key.h> 18 #include "asymmetric_keys.h" 19 20 /** 21 * verify_signature - Initiate the use of an asymmetric key to verify a signature 22 * @key: The asymmetric key to verify against 23 * @sig: The signature to check 24 * 25 * Returns 0 if successful or else an error. 26 */ 27 int verify_signature(const struct key *key, 28 const struct public_key_signature *sig) 29 { 30 const struct asymmetric_key_subtype *subtype; 31 int ret; 32 33 pr_devel("==>%s()\n", __func__); 34 35 if (key->type != &key_type_asymmetric) 36 return -EINVAL; 37 subtype = asymmetric_key_subtype(key); 38 if (!subtype || 39 !key->payload.data) 40 return -EINVAL; 41 if (!subtype->verify_signature) 42 return -ENOTSUPP; 43 44 ret = subtype->verify_signature(key, sig); 45 46 pr_devel("<==%s() = %d\n", __func__, ret); 47 return ret; 48 } 49 EXPORT_SYMBOL_GPL(verify_signature); 50