Import initial code for the SM2 cipher

This adds the SM2 algorithm defined in the Chinese standards
GB/T 32918.1-2016, GB/T 32918.2-2016, GB/T 32918.3-2016,
GB/T 32918.4-2016 and GB/T 32918.5-2017.

This is an ISC licensed implementation contributed by Ribose.inc, based
on the same code that was contributed to OpenSSL by Jack Lloyd. The port
to LibreSSL was done by Ronald Tse and Nickolay Olshevsky.

Github PR #105

I made quite a few cleanup passes on this, but more is needed, some
of which will happen in-tree before this is linked to the build.

ok deraadt inoguchi (a long time ago), jsing

1 files changed, 161 insertions, 0 deletions

diff --git a/src/lib/libcrypto/sm2/sm2_za.c b/src/lib/libcrypto/sm2/sm2_za.c
new file mode 100644
index 0000000000..2a7f2846ec
--- /dev/null
+++ b/src/lib/libcrypto/sm2/sm2_za.c
@@ -0,0 +1,161 @@
+/*      $OpenBSD: sm2_za.c,v 1.1.1.1 2021/08/18 16:04:32 tb Exp $ */
+/*
+ * Copyright (c) 2017, 2019 Ribose Inc
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef OPENSSL_NO_SM2
+
+#include <openssl/sm2.h>
+#include <openssl/evp.h>
+#include <openssl/bn.h>
+#include <string.h>
+
+int
+sm2_compute_userid_digest(uint8_t *out, const EVP_MD *digest, uint8_t *uid,
+    size_t uid_len, const EC_KEY *key)
+{
+        const EC_GROUP *group;
+        EVP_MD_CTX *hash = NULL;
+        BN_CTX *ctx = NULL;
+        BIGNUM *p, *a, *b, *xG, *yG, *xA, *yA;
+        uint8_t *buf = NULL;
+        uint16_t entla;
+        uint8_t e_byte;
+        int bytes, p_bytes;
+        int rc = 0;
+
+        if ((group = EC_KEY_get0_group(key)) == NULL)
+                goto err;
+
+        if ((hash = EVP_MD_CTX_new()) == NULL)
+                goto err;
+
+        if ((ctx = BN_CTX_new()) == NULL)
+                goto err;
+
+        if ((p = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((a = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((b = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((xG = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((yG = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((xA = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((yA = BN_CTX_get(ctx)) == NULL)
+                goto err;
+
+        memset(out, 0, EVP_MD_size(digest));
+
+        if (!EVP_DigestInit(hash, digest))
+                goto err;
+
+        /*
+         * ZA=H256(ENTLA || IDA || a || b || xG || yG || xA || yA)
+         */
+
+        if (uid_len >= 8192)
+                goto err;
+
+        entla = (unsigned short)(8 * uid_len);
+
+        e_byte = entla >> 8;
+        if (!EVP_DigestUpdate(hash, &e_byte, 1))
+                goto err;
+
+        e_byte = entla & 0xFF;
+        if (!EVP_DigestUpdate(hash, &e_byte, 1))
+                goto err;
+
+        if (!EVP_DigestUpdate(hash, uid, uid_len))
+                goto err;
+
+        if (!EC_GROUP_get_curve(group, p, a, b, ctx))
+                goto err;
+
+        p_bytes = BN_num_bytes(p);
+
+        if ((buf = calloc(1, p_bytes)) == NULL)
+                goto err;
+
+        if ((bytes = BN_num_bytes(a)) > p_bytes)
+                goto err;
+        BN_bn2bin(a, buf + p_bytes - bytes);
+        if (!EVP_DigestUpdate(hash, buf, p_bytes))
+                goto err;
+
+        if ((bytes = BN_num_bytes(b)) > p_bytes)
+                goto err;
+        memset(buf, 0, p_bytes - bytes);
+        BN_bn2bin(b, buf + p_bytes - bytes);
+        if (!EVP_DigestUpdate(hash, buf, p_bytes))
+                goto err;
+
+        if (!EC_POINT_get_affine_coordinates(group,
+            EC_GROUP_get0_generator(group), xG, yG, ctx))
+                goto err;
+
+        if ((bytes = BN_num_bytes(xG)) > p_bytes)
+                goto err;
+        memset(buf, 0, p_bytes - bytes);
+        BN_bn2bin(xG, buf + p_bytes - bytes);
+
+        if (!EVP_DigestUpdate(hash, buf, p_bytes))
+                goto err;
+
+        if ((bytes = BN_num_bytes(yG)) > p_bytes)
+                goto err;
+        memset(buf, 0, p_bytes - bytes);
+        BN_bn2bin(yG, buf + p_bytes - bytes);
+
+        if (!EVP_DigestUpdate(hash, buf, p_bytes))
+                goto err;
+
+        if (!EC_POINT_get_affine_coordinates(group,
+            EC_KEY_get0_public_key(key), xA, yA, ctx))
+                goto err;
+
+        if ((bytes = BN_num_bytes(xA)) > p_bytes)
+                goto err;
+        memset(buf, 0, p_bytes - bytes);
+        BN_bn2bin(xA, buf + p_bytes - bytes);
+
+        if (!EVP_DigestUpdate(hash, buf, p_bytes))
+                goto err;
+
+        if ((bytes = BN_num_bytes(yA)) > p_bytes)
+                goto err;
+        memset(buf, 0, p_bytes - bytes);
+        BN_bn2bin(yA, buf + p_bytes - bytes);
+
+        if (!EVP_DigestUpdate(hash, buf, p_bytes))
+                goto err;
+
+        if (!EVP_DigestFinal(hash, out, NULL))
+                goto err;
+
+        rc = 1;
+
+ err:
+        free(buf);
+        BN_CTX_free(ctx);
+        EVP_MD_CTX_free(hash);
+        return rc;
+}
+
+#endif /* OPENSSL_NO_SM2 */