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 }; 43 EXPORT_SYMBOL_GPL(pkey_id_type_name); 44 45 /* 46 * Provide a part of a description of the key for /proc/keys. 47 */ 48 static void public_key_describe(const struct key *asymmetric_key, 49 struct seq_file *m) 50 { 51 struct public_key *key = asymmetric_key->payload.data; 52 53 if (key) 54 seq_printf(m, "%s.%s", 55 pkey_id_type_name[key->id_type], key->algo->name); 56 } 57 58 /* 59 * Destroy a public key algorithm key. 60 */ 61 void public_key_destroy(void *payload) 62 { 63 struct public_key *key = payload; 64 int i; 65 66 if (key) { 67 for (i = 0; i < ARRAY_SIZE(key->mpi); i++) 68 mpi_free(key->mpi[i]); 69 kfree(key); 70 } 71 } 72 EXPORT_SYMBOL_GPL(public_key_destroy); 73 74 /* 75 * Verify a signature using a public key. 76 */ 77 int public_key_verify_signature(const struct public_key *pk, 78 const struct public_key_signature *sig) 79 { 80 const struct public_key_algorithm *algo; 81 82 BUG_ON(!pk); 83 BUG_ON(!pk->mpi[0]); 84 BUG_ON(!pk->mpi[1]); 85 BUG_ON(!sig); 86 BUG_ON(!sig->digest); 87 BUG_ON(!sig->mpi[0]); 88 89 algo = pk->algo; 90 if (!algo) { 91 if (pk->pkey_algo >= PKEY_ALGO__LAST) 92 return -ENOPKG; 93 algo = pkey_algo[pk->pkey_algo]; 94 if (!algo) 95 return -ENOPKG; 96 } 97 98 if (!algo->verify_signature) 99 return -ENOTSUPP; 100 101 if (sig->nr_mpi != algo->n_sig_mpi) { 102 pr_debug("Signature has %u MPI not %u\n", 103 sig->nr_mpi, algo->n_sig_mpi); 104 return -EINVAL; 105 } 106 107 return algo->verify_signature(pk, sig); 108 } 109 EXPORT_SYMBOL_GPL(public_key_verify_signature); 110 111 static int public_key_verify_signature_2(const struct key *key, 112 const struct public_key_signature *sig) 113 { 114 const struct public_key *pk = key->payload.data; 115 return public_key_verify_signature(pk, sig); 116 } 117 118 /* 119 * Public key algorithm asymmetric key subtype 120 */ 121 struct asymmetric_key_subtype public_key_subtype = { 122 .owner = THIS_MODULE, 123 .name = "public_key", 124 .describe = public_key_describe, 125 .destroy = public_key_destroy, 126 .verify_signature = public_key_verify_signature_2, 127 }; 128 EXPORT_SYMBOL_GPL(public_key_subtype); 129