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author | Sean Paul <seanpaul@chromium.org> | 2019-05-22 22:08:21 +0200 |
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committer | Sean Paul <seanpaul@chromium.org> | 2019-05-22 22:08:21 +0200 |
commit | 374ed5429346a021c8e2d26fafce14c5b15dedd0 (patch) | |
tree | 70739e93443494993197cc11f41c0fd0a0f3aac0 /crypto/ecrdsa.c | |
parent | video/hdmi: Add Unpack function for DRM infoframe (diff) | |
parent | Linux 5.2-rc1 (diff) | |
download | linux-374ed5429346a021c8e2d26fafce14c5b15dedd0.tar.xz linux-374ed5429346a021c8e2d26fafce14c5b15dedd0.zip |
Merge drm/drm-next into drm-misc-next
Backmerging 5.2-rc1 to -misc-next for robher
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Diffstat (limited to 'crypto/ecrdsa.c')
-rw-r--r-- | crypto/ecrdsa.c | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/crypto/ecrdsa.c b/crypto/ecrdsa.c new file mode 100644 index 000000000000..887ec21aee49 --- /dev/null +++ b/crypto/ecrdsa.c @@ -0,0 +1,296 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Elliptic Curve (Russian) Digital Signature Algorithm for Cryptographic API + * + * Copyright (c) 2019 Vitaly Chikunov <vt@altlinux.org> + * + * References: + * GOST 34.10-2018, GOST R 34.10-2012, RFC 7091, ISO/IEC 14888-3:2018. + * + * Historical references: + * GOST R 34.10-2001, RFC 4357, ISO/IEC 14888-3:2006/Amd 1:2010. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#include <linux/module.h> +#include <linux/crypto.h> +#include <crypto/streebog.h> +#include <crypto/internal/akcipher.h> +#include <crypto/akcipher.h> +#include <linux/oid_registry.h> +#include "ecrdsa_params.asn1.h" +#include "ecrdsa_pub_key.asn1.h" +#include "ecc.h" +#include "ecrdsa_defs.h" + +#define ECRDSA_MAX_SIG_SIZE (2 * 512 / 8) +#define ECRDSA_MAX_DIGITS (512 / 64) + +struct ecrdsa_ctx { + enum OID algo_oid; /* overall public key oid */ + enum OID curve_oid; /* parameter */ + enum OID digest_oid; /* parameter */ + const struct ecc_curve *curve; /* curve from oid */ + unsigned int digest_len; /* parameter (bytes) */ + const char *digest; /* digest name from oid */ + unsigned int key_len; /* @key length (bytes) */ + const char *key; /* raw public key */ + struct ecc_point pub_key; + u64 _pubp[2][ECRDSA_MAX_DIGITS]; /* point storage for @pub_key */ +}; + +static const struct ecc_curve *get_curve_by_oid(enum OID oid) +{ + switch (oid) { + case OID_gostCPSignA: + case OID_gostTC26Sign256B: + return &gost_cp256a; + case OID_gostCPSignB: + case OID_gostTC26Sign256C: + return &gost_cp256b; + case OID_gostCPSignC: + case OID_gostTC26Sign256D: + return &gost_cp256c; + case OID_gostTC26Sign512A: + return &gost_tc512a; + case OID_gostTC26Sign512B: + return &gost_tc512b; + /* The following two aren't implemented: */ + case OID_gostTC26Sign256A: + case OID_gostTC26Sign512C: + default: + return NULL; + } +} + +static int ecrdsa_verify(struct akcipher_request *req) +{ + struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); + struct ecrdsa_ctx *ctx = akcipher_tfm_ctx(tfm); + unsigned char sig[ECRDSA_MAX_SIG_SIZE]; + unsigned char digest[STREEBOG512_DIGEST_SIZE]; + unsigned int ndigits = req->dst_len / sizeof(u64); + u64 r[ECRDSA_MAX_DIGITS]; /* witness (r) */ + u64 _r[ECRDSA_MAX_DIGITS]; /* -r */ + u64 s[ECRDSA_MAX_DIGITS]; /* second part of sig (s) */ + u64 e[ECRDSA_MAX_DIGITS]; /* h \mod q */ + u64 *v = e; /* e^{-1} \mod q */ + u64 z1[ECRDSA_MAX_DIGITS]; + u64 *z2 = _r; + struct ecc_point cc = ECC_POINT_INIT(s, e, ndigits); /* reuse s, e */ + + /* + * Digest value, digest algorithm, and curve (modulus) should have the + * same length (256 or 512 bits), public key and signature should be + * twice bigger. + */ + if (!ctx->curve || + !ctx->digest || + !req->src || + !ctx->pub_key.x || + req->dst_len != ctx->digest_len || + req->dst_len != ctx->curve->g.ndigits * sizeof(u64) || + ctx->pub_key.ndigits != ctx->curve->g.ndigits || + req->dst_len * 2 != req->src_len || + WARN_ON(req->src_len > sizeof(sig)) || + WARN_ON(req->dst_len > sizeof(digest))) + return -EBADMSG; + + sg_copy_to_buffer(req->src, sg_nents_for_len(req->src, req->src_len), + sig, req->src_len); + sg_pcopy_to_buffer(req->src, + sg_nents_for_len(req->src, + req->src_len + req->dst_len), + digest, req->dst_len, req->src_len); + + vli_from_be64(s, sig, ndigits); + vli_from_be64(r, sig + ndigits * sizeof(u64), ndigits); + + /* Step 1: verify that 0 < r < q, 0 < s < q */ + if (vli_is_zero(r, ndigits) || + vli_cmp(r, ctx->curve->n, ndigits) == 1 || + vli_is_zero(s, ndigits) || + vli_cmp(s, ctx->curve->n, ndigits) == 1) + return -EKEYREJECTED; + + /* Step 2: calculate hash (h) of the message (passed as input) */ + /* Step 3: calculate e = h \mod q */ + vli_from_le64(e, digest, ndigits); + if (vli_cmp(e, ctx->curve->n, ndigits) == 1) + vli_sub(e, e, ctx->curve->n, ndigits); + if (vli_is_zero(e, ndigits)) + e[0] = 1; + + /* Step 4: calculate v = e^{-1} \mod q */ + vli_mod_inv(v, e, ctx->curve->n, ndigits); + + /* Step 5: calculate z_1 = sv \mod q, z_2 = -rv \mod q */ + vli_mod_mult_slow(z1, s, v, ctx->curve->n, ndigits); + vli_sub(_r, ctx->curve->n, r, ndigits); + vli_mod_mult_slow(z2, _r, v, ctx->curve->n, ndigits); + + /* Step 6: calculate point C = z_1P + z_2Q, and R = x_c \mod q */ + ecc_point_mult_shamir(&cc, z1, &ctx->curve->g, z2, &ctx->pub_key, + ctx->curve); + if (vli_cmp(cc.x, ctx->curve->n, ndigits) == 1) + vli_sub(cc.x, cc.x, ctx->curve->n, ndigits); + + /* Step 7: if R == r signature is valid */ + if (!vli_cmp(cc.x, r, ndigits)) + return 0; + else + return -EKEYREJECTED; +} + +int ecrdsa_param_curve(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct ecrdsa_ctx *ctx = context; + + ctx->curve_oid = look_up_OID(value, vlen); + if (!ctx->curve_oid) + return -EINVAL; + ctx->curve = get_curve_by_oid(ctx->curve_oid); + return 0; +} + +/* Optional. If present should match expected digest algo OID. */ +int ecrdsa_param_digest(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct ecrdsa_ctx *ctx = context; + int digest_oid = look_up_OID(value, vlen); + + if (digest_oid != ctx->digest_oid) + return -EINVAL; + return 0; +} + +int ecrdsa_parse_pub_key(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct ecrdsa_ctx *ctx = context; + + ctx->key = value; + ctx->key_len = vlen; + return 0; +} + +static u8 *ecrdsa_unpack_u32(u32 *dst, void *src) +{ + memcpy(dst, src, sizeof(u32)); + return src + sizeof(u32); +} + +/* Parse BER encoded subjectPublicKey. */ +static int ecrdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, + unsigned int keylen) +{ + struct ecrdsa_ctx *ctx = akcipher_tfm_ctx(tfm); + unsigned int ndigits; + u32 algo, paramlen; + u8 *params; + int err; + + err = asn1_ber_decoder(&ecrdsa_pub_key_decoder, ctx, key, keylen); + if (err < 0) + return err; + + /* Key parameters is in the key after keylen. */ + params = ecrdsa_unpack_u32(¶mlen, + ecrdsa_unpack_u32(&algo, (u8 *)key + keylen)); + + if (algo == OID_gost2012PKey256) { + ctx->digest = "streebog256"; + ctx->digest_oid = OID_gost2012Digest256; + ctx->digest_len = 256 / 8; + } else if (algo == OID_gost2012PKey512) { + ctx->digest = "streebog512"; + ctx->digest_oid = OID_gost2012Digest512; + ctx->digest_len = 512 / 8; + } else + return -ENOPKG; + ctx->algo_oid = algo; + + /* Parse SubjectPublicKeyInfo.AlgorithmIdentifier.parameters. */ + err = asn1_ber_decoder(&ecrdsa_params_decoder, ctx, params, paramlen); + if (err < 0) + return err; + /* + * Sizes of algo (set in digest_len) and curve should match + * each other. + */ + if (!ctx->curve || + ctx->curve->g.ndigits * sizeof(u64) != ctx->digest_len) + return -ENOPKG; + /* + * Key is two 256- or 512-bit coordinates which should match + * curve size. + */ + if ((ctx->key_len != (2 * 256 / 8) && + ctx->key_len != (2 * 512 / 8)) || + ctx->key_len != ctx->curve->g.ndigits * sizeof(u64) * 2) + return -ENOPKG; + + ndigits = ctx->key_len / sizeof(u64) / 2; + ctx->pub_key = ECC_POINT_INIT(ctx->_pubp[0], ctx->_pubp[1], ndigits); + vli_from_le64(ctx->pub_key.x, ctx->key, ndigits); + vli_from_le64(ctx->pub_key.y, ctx->key + ndigits * sizeof(u64), + ndigits); + + if (ecc_is_pubkey_valid_partial(ctx->curve, &ctx->pub_key)) + return -EKEYREJECTED; + + return 0; +} + +static unsigned int ecrdsa_max_size(struct crypto_akcipher *tfm) +{ + struct ecrdsa_ctx *ctx = akcipher_tfm_ctx(tfm); + + /* + * Verify doesn't need any output, so it's just informational + * for keyctl to determine the key bit size. + */ + return ctx->pub_key.ndigits * sizeof(u64); +} + +static void ecrdsa_exit_tfm(struct crypto_akcipher *tfm) +{ +} + +static struct akcipher_alg ecrdsa_alg = { + .verify = ecrdsa_verify, + .set_pub_key = ecrdsa_set_pub_key, + .max_size = ecrdsa_max_size, + .exit = ecrdsa_exit_tfm, + .base = { + .cra_name = "ecrdsa", + .cra_driver_name = "ecrdsa-generic", + .cra_priority = 100, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct ecrdsa_ctx), + }, +}; + +static int __init ecrdsa_mod_init(void) +{ + return crypto_register_akcipher(&ecrdsa_alg); +} + +static void __exit ecrdsa_mod_fini(void) +{ + crypto_unregister_akcipher(&ecrdsa_alg); +} + +module_init(ecrdsa_mod_init); +module_exit(ecrdsa_mod_fini); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Vitaly Chikunov <vt@altlinux.org>"); +MODULE_DESCRIPTION("EC-RDSA generic algorithm"); +MODULE_ALIAS_CRYPTO("ecrdsa-generic"); |