1 /* In-software asymmetric public-key crypto subtype 2 * 3 * See Documentation/crypto/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) "PKEY: "fmt 15 #include <linux/module.h> 16 #include <linux/export.h> 17 #include <linux/kernel.h> 18 #include <linux/slab.h> 19 #include <linux/seq_file.h> 20 #include <keys/asymmetric-subtype.h> 21 #include "public_key.h" 22 23 MODULE_LICENSE("GPL"); 24 25 const char *const pkey_algo_name[PKEY_ALGO__LAST] = { 26 [PKEY_ALGO_DSA] = "DSA", 27 [PKEY_ALGO_RSA] = "RSA", 28 }; 29 EXPORT_SYMBOL_GPL(pkey_algo_name); 30 31 const struct public_key_algorithm *pkey_algo[PKEY_ALGO__LAST] = { 32 #if defined(CONFIG_PUBLIC_KEY_ALGO_RSA) || \ 33 defined(CONFIG_PUBLIC_KEY_ALGO_RSA_MODULE) 34 [PKEY_ALGO_RSA] = &RSA_public_key_algorithm, 35 #endif 36 }; 37 EXPORT_SYMBOL_GPL(pkey_algo); 38 39 const char *const pkey_id_type_name[PKEY_ID_TYPE__LAST] = { 40 [PKEY_ID_PGP] = "PGP", 41 [PKEY_ID_X509] = "X509", 42 [PKEY_ID_PKCS7] = "PKCS#7", 43 }; 44 EXPORT_SYMBOL_GPL(pkey_id_type_name); 45 46 /* 47 * Provide a part of a description of the key for /proc/keys. 48 */ 49 static void public_key_describe(const struct key *asymmetric_key, 50 struct seq_file *m) 51 { 52 struct public_key *key = asymmetric_key->payload.data; 53 54 if (key) 55 seq_printf(m, "%s.%s", 56 pkey_id_type_name[key->id_type], key->algo->name); 57 } 58 59 /* 60 * Destroy a public key algorithm key. 61 */ 62 void public_key_destroy(void *payload) 63 { 64 struct public_key *key = payload; 65 int i; 66 67 if (key) { 68 for (i = 0; i < ARRAY_SIZE(key->mpi); i++) 69 mpi_free(key->mpi[i]); 70 kfree(key); 71 } 72 } 73 EXPORT_SYMBOL_GPL(public_key_destroy); 74 75 /* 76 * Verify a signature using a public key. 77 */ 78 int public_key_verify_signature(const struct public_key *pk, 79 const struct public_key_signature *sig) 80 { 81 const struct public_key_algorithm *algo; 82 83 BUG_ON(!pk); 84 BUG_ON(!pk->mpi[0]); 85 BUG_ON(!pk->mpi[1]); 86 BUG_ON(!sig); 87 BUG_ON(!sig->digest); 88 BUG_ON(!sig->mpi[0]); 89 90 algo = pk->algo; 91 if (!algo) { 92 if (pk->pkey_algo >= PKEY_ALGO__LAST) 93 return -ENOPKG; 94 algo = pkey_algo[pk->pkey_algo]; 95 if (!algo) 96 return -ENOPKG; 97 } 98 99 if (!algo->verify_signature) 100 return -ENOTSUPP; 101 102 if (sig->nr_mpi != algo->n_sig_mpi) { 103 pr_debug("Signature has %u MPI not %u\n", 104 sig->nr_mpi, algo->n_sig_mpi); 105 return -EINVAL; 106 } 107 108 return algo->verify_signature(pk, sig); 109 } 110 EXPORT_SYMBOL_GPL(public_key_verify_signature); 111 112 static int public_key_verify_signature_2(const struct key *key, 113 const struct public_key_signature *sig) 114 { 115 const struct public_key *pk = key->payload.data; 116 return public_key_verify_signature(pk, sig); 117 } 118 119 /* 120 * Public key algorithm asymmetric key subtype 121 */ 122 struct asymmetric_key_subtype public_key_subtype = { 123 .owner = THIS_MODULE, 124 .name = "public_key", 125 .name_len = sizeof("public_key") - 1, 126 .describe = public_key_describe, 127 .destroy = public_key_destroy, 128 .verify_signature = public_key_verify_signature_2, 129 }; 130 EXPORT_SYMBOL_GPL(public_key_subtype); 131