diff options
Diffstat (limited to 'crypto/asymmetric_keys/rsa.c')
| -rw-r--r-- | crypto/asymmetric_keys/rsa.c | 278 |
1 files changed, 0 insertions, 278 deletions
diff --git a/crypto/asymmetric_keys/rsa.c b/crypto/asymmetric_keys/rsa.c deleted file mode 100644 index 508b57b77..000000000 --- a/crypto/asymmetric_keys/rsa.c +++ /dev/null @@ -1,278 +0,0 @@ -/* RSA asymmetric public-key algorithm [RFC3447] - * - * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. - * Written by David Howells (dhowells@redhat.com) - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public Licence - * as published by the Free Software Foundation; either version - * 2 of the Licence, or (at your option) any later version. - */ - -#define pr_fmt(fmt) "RSA: "fmt -#include <linux/module.h> -#include <linux/kernel.h> -#include <linux/slab.h> -#include <crypto/algapi.h> -#include "public_key.h" - -MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("RSA Public Key Algorithm"); - -#define kenter(FMT, ...) \ - pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__) -#define kleave(FMT, ...) \ - pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__) - -/* - * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2]. - */ -static const u8 RSA_digest_info_MD5[] = { - 0x30, 0x20, 0x30, 0x0C, 0x06, 0x08, - 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* OID */ - 0x05, 0x00, 0x04, 0x10 -}; - -static const u8 RSA_digest_info_SHA1[] = { - 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, - 0x2B, 0x0E, 0x03, 0x02, 0x1A, - 0x05, 0x00, 0x04, 0x14 -}; - -static const u8 RSA_digest_info_RIPE_MD_160[] = { - 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, - 0x2B, 0x24, 0x03, 0x02, 0x01, - 0x05, 0x00, 0x04, 0x14 -}; - -static const u8 RSA_digest_info_SHA224[] = { - 0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, - 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, - 0x05, 0x00, 0x04, 0x1C -}; - -static const u8 RSA_digest_info_SHA256[] = { - 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, - 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, - 0x05, 0x00, 0x04, 0x20 -}; - -static const u8 RSA_digest_info_SHA384[] = { - 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, - 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, - 0x05, 0x00, 0x04, 0x30 -}; - -static const u8 RSA_digest_info_SHA512[] = { - 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, - 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, - 0x05, 0x00, 0x04, 0x40 -}; - -static const struct { - const u8 *data; - size_t size; -} RSA_ASN1_templates[PKEY_HASH__LAST] = { -#define _(X) { RSA_digest_info_##X, sizeof(RSA_digest_info_##X) } - [HASH_ALGO_MD5] = _(MD5), - [HASH_ALGO_SHA1] = _(SHA1), - [HASH_ALGO_RIPE_MD_160] = _(RIPE_MD_160), - [HASH_ALGO_SHA256] = _(SHA256), - [HASH_ALGO_SHA384] = _(SHA384), - [HASH_ALGO_SHA512] = _(SHA512), - [HASH_ALGO_SHA224] = _(SHA224), -#undef _ -}; - -/* - * RSAVP1() function [RFC3447 sec 5.2.2] - */ -static int RSAVP1(const struct public_key *key, MPI s, MPI *_m) -{ - MPI m; - int ret; - - /* (1) Validate 0 <= s < n */ - if (mpi_cmp_ui(s, 0) < 0) { - kleave(" = -EBADMSG [s < 0]"); - return -EBADMSG; - } - if (mpi_cmp(s, key->rsa.n) >= 0) { - kleave(" = -EBADMSG [s >= n]"); - return -EBADMSG; - } - - m = mpi_alloc(0); - if (!m) - return -ENOMEM; - - /* (2) m = s^e mod n */ - ret = mpi_powm(m, s, key->rsa.e, key->rsa.n); - if (ret < 0) { - mpi_free(m); - return ret; - } - - *_m = m; - return 0; -} - -/* - * Integer to Octet String conversion [RFC3447 sec 4.1] - */ -static int RSA_I2OSP(MPI x, size_t xLen, u8 **pX) -{ - unsigned X_size, x_size; - int X_sign; - u8 *X; - - /* Make sure the string is the right length. The number should begin - * with { 0x00, 0x01, ... } so we have to account for 15 leading zero - * bits not being reported by MPI. - */ - x_size = mpi_get_nbits(x); - pr_devel("size(x)=%u xLen*8=%zu\n", x_size, xLen * 8); - if (x_size != xLen * 8 - 15) - return -ERANGE; - - X = mpi_get_buffer(x, &X_size, &X_sign); - if (!X) - return -ENOMEM; - if (X_sign < 0) { - kfree(X); - return -EBADMSG; - } - if (X_size != xLen - 1) { - kfree(X); - return -EBADMSG; - } - - *pX = X; - return 0; -} - -/* - * Perform the RSA signature verification. - * @H: Value of hash of data and metadata - * @EM: The computed signature value - * @k: The size of EM (EM[0] is an invalid location but should hold 0x00) - * @hash_size: The size of H - * @asn1_template: The DigestInfo ASN.1 template - * @asn1_size: Size of asm1_template[] - */ -static int RSA_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size, - const u8 *asn1_template, size_t asn1_size) -{ - unsigned PS_end, T_offset, i; - - kenter(",,%zu,%zu,%zu", k, hash_size, asn1_size); - - if (k < 2 + 1 + asn1_size + hash_size) - return -EBADMSG; - - /* Decode the EMSA-PKCS1-v1_5 */ - if (EM[1] != 0x01) { - kleave(" = -EBADMSG [EM[1] == %02u]", EM[1]); - return -EBADMSG; - } - - T_offset = k - (asn1_size + hash_size); - PS_end = T_offset - 1; - if (EM[PS_end] != 0x00) { - kleave(" = -EBADMSG [EM[T-1] == %02u]", EM[PS_end]); - return -EBADMSG; - } - - for (i = 2; i < PS_end; i++) { - if (EM[i] != 0xff) { - kleave(" = -EBADMSG [EM[PS%x] == %02u]", i - 2, EM[i]); - return -EBADMSG; - } - } - - if (crypto_memneq(asn1_template, EM + T_offset, asn1_size) != 0) { - kleave(" = -EBADMSG [EM[T] ASN.1 mismatch]"); - return -EBADMSG; - } - - if (crypto_memneq(H, EM + T_offset + asn1_size, hash_size) != 0) { - kleave(" = -EKEYREJECTED [EM[T] hash mismatch]"); - return -EKEYREJECTED; - } - - kleave(" = 0"); - return 0; -} - -/* - * Perform the verification step [RFC3447 sec 8.2.2]. - */ -static int RSA_verify_signature(const struct public_key *key, - const struct public_key_signature *sig) -{ - size_t tsize; - int ret; - - /* Variables as per RFC3447 sec 8.2.2 */ - const u8 *H = sig->digest; - u8 *EM = NULL; - MPI m = NULL; - size_t k; - - kenter(""); - - if (!RSA_ASN1_templates[sig->pkey_hash_algo].data) - return -ENOTSUPP; - - /* (1) Check the signature size against the public key modulus size */ - k = mpi_get_nbits(key->rsa.n); - tsize = mpi_get_nbits(sig->rsa.s); - - /* According to RFC 4880 sec 3.2, length of MPI is computed starting - * from most significant bit. So the RFC 3447 sec 8.2.2 size check - * must be relaxed to conform with shorter signatures - so we fail here - * only if signature length is longer than modulus size. - */ - pr_devel("step 1: k=%zu size(S)=%zu\n", k, tsize); - if (k < tsize) { - ret = -EBADMSG; - goto error; - } - - /* Round up and convert to octets */ - k = (k + 7) / 8; - - /* (2b) Apply the RSAVP1 verification primitive to the public key */ - ret = RSAVP1(key, sig->rsa.s, &m); - if (ret < 0) - goto error; - - /* (2c) Convert the message representative (m) to an encoded message - * (EM) of length k octets. - * - * NOTE! The leading zero byte is suppressed by MPI, so we pass a - * pointer to the _preceding_ byte to RSA_verify()! - */ - ret = RSA_I2OSP(m, k, &EM); - if (ret < 0) - goto error; - - ret = RSA_verify(H, EM - 1, k, sig->digest_size, - RSA_ASN1_templates[sig->pkey_hash_algo].data, - RSA_ASN1_templates[sig->pkey_hash_algo].size); - -error: - kfree(EM); - mpi_free(m); - kleave(" = %d", ret); - return ret; -} - -const struct public_key_algorithm RSA_public_key_algorithm = { - .name = "RSA", - .n_pub_mpi = 2, - .n_sec_mpi = 3, - .n_sig_mpi = 1, - .verify_signature = RSA_verify_signature, -}; -EXPORT_SYMBOL_GPL(RSA_public_key_algorithm); |