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 #define pr_fmt(fmt) "SIG: "fmt 15 #include <keys/asymmetric-subtype.h> 16 #include <linux/module.h> 17 #include <linux/err.h> 18 #include <crypto/public_key.h> 19 #include "asymmetric_keys.h" 20 21 /** 22 * verify_signature - Initiate the use of an asymmetric key to verify a signature 23 * @key: The asymmetric key to verify against 24 * @sig: The signature to check 25 * 26 * Returns 0 if successful or else an error. 27 */ 28 int verify_signature(const struct key *key, 29 const struct public_key_signature *sig) 30 { 31 const struct asymmetric_key_subtype *subtype; 32 int ret; 33 34 pr_devel("==>%s()\n", __func__); 35 36 if (key->type != &key_type_asymmetric) 37 return -EINVAL; 38 subtype = asymmetric_key_subtype(key); 39 if (!subtype || 40 !key->payload.data) 41 return -EINVAL; 42 if (!subtype->verify_signature) 43 return -ENOTSUPP; 44 45 ret = subtype->verify_signature(key, sig); 46 47 pr_devel("<==%s() = %d\n", __func__, ret); 48 return ret; 49 } 50 EXPORT_SYMBOL_GPL(verify_signature); 51