This new module implement the SM2 public key algorithm. It was published by State Encryption Management Bureau, China. List of specifications for SM2 elliptic curve public key cryptography: * GM/T 0003.1-2012 * GM/T 0003.2-2012 * GM/T 0003.3-2012 * GM/T 0003.4-2012 * GM/T 0003.5-2012 IETF: https://tools.ietf.org/html/draft-shen-sm2-ecdsa-02 oscca: http://www.oscca.gov.cn/sca/xxgk/2010-12/17/content_1002386.shtml scctc: http://www.gmbz.org.cn/main/bzlb.html Signed-off-by: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx> --- crypto/Kconfig | 17 ++ crypto/Makefile | 8 + crypto/sm2.c | 498 +++++++++++++++++++++++++++++++++++++++ crypto/sm2signature.asn1 | 4 + include/crypto/sm2.h | 25 ++ 5 files changed, 552 insertions(+) create mode 100644 crypto/sm2.c create mode 100644 crypto/sm2signature.asn1 create mode 100644 include/crypto/sm2.h diff --git a/crypto/Kconfig b/crypto/Kconfig index c24a47406f8f..1e7f9410288f 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -260,6 +260,23 @@ config CRYPTO_ECRDSA standard algorithms (called GOST algorithms). Only signature verification is implemented. +config CRYPTO_SM2 + tristate "SM2 algorithm" + select CRYPTO_SM3 + select CRYPTO_AKCIPHER + select CRYPTO_MANAGER + select MPILIB + select ASN1 + help + Generic implementation of the SM2 public key algorithm. It was + published by State Encryption Management Bureau, China. + as specified by OSCCA GM/T 0003.1-2012 -- 0003.5-2012. + + References: + https://tools.ietf.org/html/draft-shen-sm2-ecdsa-02 + http://www.oscca.gov.cn/sca/xxgk/2010-12/17/content_1002386.shtml + http://www.gmbz.org.cn/main/bzlb.html + config CRYPTO_CURVE25519 tristate "Curve25519 algorithm" select CRYPTO_KPP diff --git a/crypto/Makefile b/crypto/Makefile index 4ca12b6044f7..b279483fba50 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -42,6 +42,14 @@ rsa_generic-y += rsa_helper.o rsa_generic-y += rsa-pkcs1pad.o obj-$(CONFIG_CRYPTO_RSA) += rsa_generic.o +$(obj)/sm2signature.asn1.o: $(obj)/sm2signature.asn1.c $(obj)/sm2signature.asn1.h +$(obj)/sm2.o: $(obj)/sm2signature.asn1.h + +sm2_generic-y += sm2signature.asn1.o +sm2_generic-y += sm2.o + +obj-$(CONFIG_CRYPTO_SM2) += sm2_generic.o + crypto_acompress-y := acompress.o crypto_acompress-y += scompress.o obj-$(CONFIG_CRYPTO_ACOMP2) += crypto_acompress.o diff --git a/crypto/sm2.c b/crypto/sm2.c new file mode 100644 index 000000000000..33e022d47e4a --- /dev/null +++ b/crypto/sm2.c @@ -0,0 +1,498 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * SM2 asymmetric public-key algorithm + * as specified by OSCCA GM/T 0003.1-2012 -- 0003.5-2012 SM2 and + * described at https://tools.ietf.org/html/draft-shen-sm2-ecdsa-02 + * + * Copyright (c) 2020, Alibaba Group. + * Authors: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx> + */ + +#include <linux/module.h> +#include <linux/mpi.h> +#include <crypto/internal/akcipher.h> +#include <crypto/akcipher.h> +#include <crypto/hash.h> +#include <crypto/sm3_base.h> +#include <crypto/rng.h> +#include <crypto/sm2.h> +#include "sm2signature.asn1.h" + +#define MPI_NBYTES(m) ((mpi_get_nbits(m) + 7) / 8) + +struct ecc_domain_parms { + const char *desc; /* Description of the curve. */ + unsigned int nbits; /* Number of bits. */ + unsigned int fips:1; /* True if this is a FIPS140-2 approved curve */ + + /* The model describing this curve. This is mainly used to select + * the group equation. + */ + enum gcry_mpi_ec_models model; + + /* The actual ECC dialect used. This is used for curve specific + * optimizations and to select encodings etc. + */ + enum ecc_dialects dialect; + + const char *p; /* The prime defining the field. */ + const char *a, *b; /* The coefficients. For Twisted Edwards + * Curves b is used for d. For Montgomery + * Curves (a,b) has ((A-2)/4,B^-1). + */ + const char *n; /* The order of the base point. */ + const char *g_x, *g_y; /* Base point. */ + unsigned int h; /* Cofactor. */ +}; + +static const struct ecc_domain_parms sm2_ecp = { + .desc = "sm2p256v1", + .nbits = 256, + .fips = 0, + .model = MPI_EC_WEIERSTRASS, + .dialect = ECC_DIALECT_STANDARD, + .p = "0xfffffffeffffffffffffffffffffffffffffffff00000000ffffffffffffffff", + .a = "0xfffffffeffffffffffffffffffffffffffffffff00000000fffffffffffffffc", + .b = "0x28e9fa9e9d9f5e344d5a9e4bcf6509a7f39789f515ab8f92ddbcbd414d940e93", + .n = "0xfffffffeffffffffffffffffffffffff7203df6b21c6052b53bbf40939d54123", + .g_x = "0x32c4ae2c1f1981195f9904466a39c9948fe30bbff2660be1715a4589334c74c7", + .g_y = "0xbc3736a2f4f6779c59bdcee36b692153d0a9877cc62a474002df32e52139f0a0", + .h = 1 +}; + +static int sm2_ec_ctx_init(struct mpi_ec_ctx *ec) +{ + const struct ecc_domain_parms *ecp = &sm2_ecp; + MPI p, a, b; + MPI x, y; + int rc = -EINVAL; + + p = mpi_scanval(ecp->p); + a = mpi_scanval(ecp->a); + b = mpi_scanval(ecp->b); + if (!p || !a || !b) + goto free_p; + + x = mpi_scanval(ecp->g_x); + y = mpi_scanval(ecp->g_y); + if (!x || !y) + goto free; + + /* mpi_ec_setup_elliptic_curve */ + ec->G = mpi_point_new(0); + if (!ec->G) + goto free; + + mpi_set(ec->G->x, x); + mpi_set(ec->G->y, y); + mpi_set_ui(ec->G->z, 1); + + ec->n = mpi_scanval(ecp->n); + if (!ec->n) { + mpi_point_release(ec->G); + goto free; + } + + ec->h = ecp->h; + ec->name = ecp->desc; + mpi_ec_init(ec, ecp->model, ecp->dialect, 0, p, a, b); + + rc = 0; + +free: + mpi_free(x); + mpi_free(y); +free_p: + mpi_free(p); + mpi_free(a); + mpi_free(b); + + return rc; +} + +static void sm2_ec_ctx_deinit(struct mpi_ec_ctx *ec) +{ + mpi_free(ec->n); + mpi_point_release(ec->G); + + mpi_ec_deinit(ec); + + memset(ec, 0, sizeof(*ec)); +} + +static int sm2_ec_ctx_reset(struct mpi_ec_ctx *ec) +{ + sm2_ec_ctx_deinit(ec); + return sm2_ec_ctx_init(ec); +} + +/* RESULT must have been initialized and is set on success to the + * point given by VALUE. + */ +static int sm2_ecc_os2ec(MPI_POINT result, MPI value) +{ + int rc; + size_t n; + const unsigned char *buf; + unsigned char *buf_memory; + MPI x, y; + + n = (mpi_get_nbits(value)+7)/8; + buf_memory = kmalloc(n, GFP_KERNEL); + rc = mpi_print(GCRYMPI_FMT_USG, buf_memory, n, &n, value); + if (rc) { + kfree(buf_memory); + return rc; + } + buf = buf_memory; + + if (n < 1) { + kfree(buf_memory); + return -EINVAL; + } + if (*buf != 4) { + kfree(buf_memory); + return -EINVAL; /* No support for point compression. */ + } + if (((n-1)%2)) { + kfree(buf_memory); + return -EINVAL; + } + n = (n-1)/2; + x = mpi_read_raw_data(buf + 1, n); + if (!x) { + kfree(buf_memory); + return -ENOMEM; + } + y = mpi_read_raw_data(buf + 1 + n, n); + kfree(buf_memory); + if (!y) { + mpi_free(x); + return -ENOMEM; + } + + mpi_normalize(x); + mpi_normalize(y); + + mpi_set(result->x, x); + mpi_set(result->y, y); + mpi_set_ui(result->z, 1); + + mpi_free(x); + mpi_free(y); + + return 0; +} + +struct sm2_signature_ctx { + MPI sig_r; + MPI sig_s; +}; + +int sm2_get_signature_r(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct sm2_signature_ctx *sig = context; + + if (!value || !vlen) + return -EINVAL; + + sig->sig_r = mpi_read_raw_data(value, vlen); + if (!sig->sig_r) + return -ENOMEM; + + return 0; +} + +int sm2_get_signature_s(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct sm2_signature_ctx *sig = context; + + if (!value || !vlen) + return -EINVAL; + + sig->sig_s = mpi_read_raw_data(value, vlen); + if (!sig->sig_s) + return -ENOMEM; + + return 0; +} + +static int sm2_z_digest_update(struct shash_desc *desc, + MPI m, unsigned int pbytes) +{ + static const unsigned char zero[32]; + unsigned char *in; + unsigned int inlen; + + in = mpi_get_buffer(m, &inlen, NULL); + if (!in) + return -EINVAL; + + if (inlen < pbytes) { + /* padding with zero */ + crypto_sm3_update(desc, zero, pbytes - inlen); + crypto_sm3_update(desc, in, inlen); + } else if (inlen > pbytes) { + /* skip the starting zero */ + crypto_sm3_update(desc, in + inlen - pbytes, pbytes); + } else { + crypto_sm3_update(desc, in, inlen); + } + + kfree(in); + return 0; +} + +static int sm2_z_digest_update_point(struct shash_desc *desc, + MPI_POINT point, struct mpi_ec_ctx *ec, unsigned int pbytes) +{ + MPI x, y; + int ret = -EINVAL; + + x = mpi_new(0); + y = mpi_new(0); + + if (!mpi_ec_get_affine(x, y, point, ec) && + !sm2_z_digest_update(desc, x, pbytes) && + !sm2_z_digest_update(desc, y, pbytes)) + ret = 0; + + mpi_free(x); + mpi_free(y); + return ret; +} + +int sm2_compute_z_digest(struct crypto_akcipher *tfm, + const unsigned char *id, size_t id_len, + unsigned char dgst[SM3_DIGEST_SIZE]) +{ + struct mpi_ec_ctx *ec = akcipher_tfm_ctx(tfm); + uint16_t bits_len; + unsigned char entl[2]; + SHASH_DESC_ON_STACK(desc, NULL); + unsigned int pbytes; + + if (id_len > (USHRT_MAX / 8) || !ec->Q) + return -EINVAL; + + bits_len = (uint16_t)(id_len * 8); + entl[0] = bits_len >> 8; + entl[1] = bits_len & 0xff; + + pbytes = MPI_NBYTES(ec->p); + + /* ZA = H256(ENTLA | IDA | a | b | xG | yG | xA | yA) */ + sm3_base_init(desc); + crypto_sm3_update(desc, entl, 2); + crypto_sm3_update(desc, id, id_len); + + if (sm2_z_digest_update(desc, ec->a, pbytes) || + sm2_z_digest_update(desc, ec->b, pbytes) || + sm2_z_digest_update_point(desc, ec->G, ec, pbytes) || + sm2_z_digest_update_point(desc, ec->Q, ec, pbytes)) + return -EINVAL; + + crypto_sm3_finup(desc, NULL, 0, dgst); + return 0; +} +EXPORT_SYMBOL(sm2_compute_z_digest); + +static int _sm2_verify(struct mpi_ec_ctx *ec, MPI hash, MPI sig_r, MPI sig_s) +{ + int rc = -EINVAL; + struct gcry_mpi_point sG, tP; + MPI t = NULL; + MPI x1 = NULL, y1 = NULL; + + mpi_point_init(&sG); + mpi_point_init(&tP); + x1 = mpi_new(0); + y1 = mpi_new(0); + t = mpi_new(0); + + /* r, s in [1, n-1] */ + if (mpi_cmp_ui(sig_r, 1) < 0 || mpi_cmp(sig_r, ec->n) > 0 || + mpi_cmp_ui(sig_s, 1) < 0 || mpi_cmp(sig_s, ec->n) > 0) { + goto leave; + } + + /* t = (r + s) % n, t == 0 */ + mpi_addm(t, sig_r, sig_s, ec->n); + if (mpi_cmp_ui(t, 0) == 0) + goto leave; + + /* sG + tP = (x1, y1) */ + rc = -EBADMSG; + mpi_ec_mul_point(&sG, sig_s, ec->G, ec); + mpi_ec_mul_point(&tP, t, ec->Q, ec); + mpi_ec_add_points(&sG, &sG, &tP, ec); + if (mpi_ec_get_affine(x1, y1, &sG, ec)) + goto leave; + + /* R = (e + x1) % n */ + mpi_addm(t, hash, x1, ec->n); + + /* check R == r */ + rc = -EKEYREJECTED; + if (mpi_cmp(t, sig_r)) + goto leave; + + rc = 0; + +leave: + mpi_point_free_parts(&sG); + mpi_point_free_parts(&tP); + mpi_free(x1); + mpi_free(y1); + mpi_free(t); + + return rc; +} + +static int sm2_verify(struct akcipher_request *req) +{ + struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); + struct mpi_ec_ctx *ec = akcipher_tfm_ctx(tfm); + unsigned char *buffer; + struct sm2_signature_ctx sig; + MPI hash; + int ret; + + if (unlikely(!ec->Q)) + return -EINVAL; + + buffer = kmalloc(req->src_len + req->dst_len, GFP_KERNEL); + if (!buffer) + return -ENOMEM; + + sg_pcopy_to_buffer(req->src, + sg_nents_for_len(req->src, req->src_len + req->dst_len), + buffer, req->src_len + req->dst_len, 0); + + sig.sig_r = NULL; + sig.sig_s = NULL; + ret = asn1_ber_decoder(&sm2signature_decoder, &sig, buffer, req->src_len); + if (ret) + goto error; + + ret = -ENOMEM; + hash = mpi_read_raw_data(buffer + req->src_len, req->dst_len); + if (!hash) + goto error; + + ret = _sm2_verify(ec, hash, sig.sig_r, sig.sig_s); + + mpi_free(hash); +error: + mpi_free(sig.sig_r); + mpi_free(sig.sig_s); + kfree(buffer); + return ret; +} + +static int sm2_set_pub_key(struct crypto_akcipher *tfm, const void *key, + unsigned int keylen) +{ + struct mpi_ec_ctx *ec = akcipher_tfm_ctx(tfm); + MPI a; + int rc; + + rc = sm2_ec_ctx_reset(ec); + if (rc) + return rc; + + ec->Q = mpi_point_new(0); + if (!ec->Q) + return -ENOMEM; + + /* include the uncompressed flag '0x04' */ + rc = -ENOMEM; + a = mpi_read_raw_data(key, keylen); + if (!a) + goto error; + + mpi_normalize(a); + rc = sm2_ecc_os2ec(ec->Q, a); + mpi_free(a); + if (rc) + goto error; + + return 0; + +error: + mpi_point_release(ec->Q); + ec->Q = NULL; + return rc; +} + +static int sm2_set_priv_key(struct crypto_akcipher *tfm, const void *key, + unsigned int keylen) +{ + struct mpi_ec_ctx *ec = akcipher_tfm_ctx(tfm); + int rc; + + rc = sm2_ec_ctx_reset(ec); + if (rc) + return rc; + + ec->d = mpi_read_raw_data(key, keylen); + if (!ec->d) + return -ENOMEM; + + /* compute pubkey if it not exist */ + if (!ec->Q) { + ec->Q = mpi_point_new(0); + if (!ec->Q) + return -ENOMEM; + mpi_ec_mul_point(ec->Q, ec->d, ec->G, ec); + } + + return 0; +} + +static unsigned int sm2_max_size(struct crypto_akcipher *tfm) +{ + /* Unlimited max size */ + return PAGE_SIZE; +} + +static void sm2_exit_tfm(struct crypto_akcipher *tfm) +{ + struct mpi_ec_ctx *ec = akcipher_tfm_ctx(tfm); + + mpi_ec_deinit(ec); +} + +static struct akcipher_alg sm2 = { + .verify = sm2_verify, + .set_priv_key = sm2_set_priv_key, + .set_pub_key = sm2_set_pub_key, + .max_size = sm2_max_size, + .exit = sm2_exit_tfm, + .base = { + .cra_name = "sm2", + .cra_driver_name = "sm2-generic", + .cra_priority = 100, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct mpi_ec_ctx), + }, +}; + +static int sm2_init(void) +{ + return crypto_register_akcipher(&sm2); +} + +static void sm2_exit(void) +{ + crypto_unregister_akcipher(&sm2); +} + +subsys_initcall(sm2_init); +module_exit(sm2_exit); + +MODULE_ALIAS_CRYPTO("sm2"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("SM2 generic algorithm"); diff --git a/crypto/sm2signature.asn1 b/crypto/sm2signature.asn1 new file mode 100644 index 000000000000..ab8c0b754d21 --- /dev/null +++ b/crypto/sm2signature.asn1 @@ -0,0 +1,4 @@ +Sm2Signature ::= SEQUENCE { + sig_r INTEGER ({ sm2_get_signature_r }), + sig_s INTEGER ({ sm2_get_signature_s }) +} diff --git a/include/crypto/sm2.h b/include/crypto/sm2.h new file mode 100644 index 000000000000..af452556dcd4 --- /dev/null +++ b/include/crypto/sm2.h @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * sm2.h - SM2 asymmetric public-key algorithm + * as specified by OSCCA GM/T 0003.1-2012 -- 0003.5-2012 SM2 and + * described at https://tools.ietf.org/html/draft-shen-sm2-ecdsa-02 + * + * Copyright (c) 2020, Alibaba Group. + * Written by Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx> + */ + +#ifndef _CRYPTO_SM2_H +#define _CRYPTO_SM2_H + +#include <crypto/sm3.h> +#include <crypto/akcipher.h> + +/* The default user id as specified in GM/T 0009-2012 */ +#define SM2_DEFAULT_USERID "1234567812345678" +#define SM2_DEFAULT_USERID_LEN 16 + +extern int sm2_compute_z_digest(struct crypto_akcipher *tfm, + const unsigned char *id, size_t id_len, + unsigned char dgst[SM3_DIGEST_SIZE]); + +#endif /* _CRYPTO_SM2_H */ -- 2.17.1
