[6/7] crypto: Implement ECDSA algorithm by gcrypt

Commit Message

Lei He June 13, 2022, 8:45 a.m. UTC

Implement ECDSA algorithm by gcrypt

Signed-off-by: lei he <[e-mail]>
---
 crypto/akcipher-gcrypt.c.inc | 400 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 400 insertions(+)

Comments

Daniel P. Berrangé June 17, 2022, 1:41 p.m. UTC | #1

On Mon, Jun 13, 2022 at 04:45:30PM +0800, Lei He wrote:
> Implement ECDSA algorithm by gcrypt
> 
> Signed-off-by: lei he <[e-mail]>
> ---
>  crypto/akcipher-gcrypt.c.inc | 400 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 400 insertions(+)

Reviewed-by: Daniel P. Berrangé <[e-mail]>


With regards,
Daniel

Patch

diff --git a/crypto/akcipher-gcrypt.c.inc b/crypto/akcipher-gcrypt.c.inc
index abb1fb272e..24377bbec6 100644
--- a/crypto/akcipher-gcrypt.c.inc
+++ b/crypto/akcipher-gcrypt.c.inc
@@ -28,6 +28,7 @@ 
 #include "qapi/error.h"
 #include "sysemu/cryptodev.h"
 #include "rsakey.h"
+#include "ecdsakey.h"
 
 typedef struct QCryptoGcryptRSA {
     QCryptoAkCipher akcipher;
@@ -36,6 +37,13 @@  typedef struct QCryptoGcryptRSA {
     QCryptoHashAlgorithm hash_alg;
 } QCryptoGcryptRSA;
 
+typedef struct QCryptoGcryptECDSA {
+    QCryptoAkCipher akcipher;
+    gcry_sexp_t key;
+    QCryptoCurveID curve_id;
+    const char *curve_name;
+} QCryptoGcryptECDSA;
+
 static void qcrypto_gcrypt_rsa_free(QCryptoAkCipher *akcipher)
 {
     QCryptoGcryptRSA *rsa = (QCryptoGcryptRSA *)akcipher;
@@ -53,6 +61,12 @@  static QCryptoGcryptRSA *qcrypto_gcrypt_rsa_new(
     const uint8_t *key,  size_t keylen,
     Error **errp);
 
+static QCryptoGcryptECDSA *qcrypto_gcrypt_ecdsa_new(
+    const QCryptoAkCipherOptionsECDSA *opts,
+    QCryptoAkCipherKeyType type,
+    const uint8_t *key, size_t keylen,
+    Error **errp);
+
 QCryptoAkCipher *qcrypto_akcipher_new(const QCryptoAkCipherOptions *opts,
                                       QCryptoAkCipherKeyType type,
                                       const uint8_t *key, size_t keylen,
@@ -63,6 +77,10 @@  QCryptoAkCipher *qcrypto_akcipher_new(const QCryptoAkCipherOptions *opts,
         return (QCryptoAkCipher *)qcrypto_gcrypt_rsa_new(
             &opts->u.rsa, type, key, keylen, errp);
 
+    case QCRYPTO_AKCIPHER_ALG_ECDSA:
+        return (QCryptoAkCipher *)qcrypto_gcrypt_ecdsa_new(
+            &opts->u.ecdsa, type, key, keylen, errp);
+
     default:
         error_setg(errp, "Unsupported algorithm: %u", opts->alg);
         return NULL;
@@ -564,6 +582,377 @@  error:
     return NULL;
 }
 
+static int qcrypto_gcrypt_parse_curve_id(QCryptoGcryptECDSA *ecdsa,
+    const QCryptoAkCipherOptionsECDSA *opts, Error **errp)
+{
+    /* ECDSA algorithm can't used for encryption */
+    ecdsa->akcipher.max_plaintext_len = 0;
+    ecdsa->akcipher.max_ciphertext_len = 0;
+
+    switch (opts->curve_id) {
+    case QCRYPTO_CURVE_ID_NIST_P192:
+        ecdsa->curve_name = "nistp192";
+        ecdsa->akcipher.max_signature_len =
+            qcrypto_akcipher_ecdsasig_x9_62_size(192 / 8);
+        ecdsa->akcipher.max_dgst_len = 192 / 8;
+        break;
+
+    case QCRYPTO_CURVE_ID_NIST_P256:
+        ecdsa->curve_name = "nistp256";
+        ecdsa->akcipher.max_signature_len =
+            qcrypto_akcipher_ecdsasig_x9_62_size(256 / 8);
+        ecdsa->akcipher.max_dgst_len = 256 / 8;
+        break;
+
+    case QCRYPTO_CURVE_ID_NIST_P384:
+        ecdsa->curve_name = "nistp384";
+        ecdsa->akcipher.max_signature_len =
+            qcrypto_akcipher_ecdsasig_x9_62_size(384 / 8);
+        ecdsa->akcipher.max_dgst_len = 256 / 8;
+        break;
+
+    default:
+        error_setg(errp, "Unknown curve id: %d", opts->curve_id);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int qcrypto_gcrypt_parse_ecdsa_private_key(
+    QCryptoGcryptECDSA *ecdsa, const char *curve_name,
+    const uint8_t *key, size_t keylen,
+    Error **errp)
+{
+    g_autoptr(QCryptoAkCipherECDSAKey) ecdsa_key =
+        qcrypto_akcipher_ecdsakey_parse(QCRYPTO_AKCIPHER_KEY_TYPE_PRIVATE,
+                                        key, keylen, errp);
+    gcry_mpi_t d = NULL;
+    gcry_error_t err;
+    int ret = -1;
+
+    if (!ecdsa_key) {
+        return ret;
+    }
+
+    err = gcry_mpi_scan(&d, GCRYMPI_FMT_USG, ecdsa_key->priv.data,
+                        ecdsa_key->priv.len, NULL);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to parse ECDSA parivate key: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        return ret;
+    }
+
+    err = gcry_sexp_build(&ecdsa->key, NULL,
+        "(private-key (ecc (curve %s) (d %m)))", curve_name, d);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to build ECDSA parivate key: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+
+    ret = 0;
+
+cleanup:
+    gcry_mpi_release(d);
+    return ret;
+}
+
+static int qcrypto_gcrypt_parse_ecdsa_public_key(
+    QCryptoGcryptECDSA *ecdsa, const char *curve_name,
+    const uint8_t *key, size_t keylen,
+    Error **errp)
+{
+    gcry_mpi_t q = NULL;
+    gcry_error_t err;
+    int ret = -1;
+
+    err = gcry_mpi_scan(&q, GCRYMPI_FMT_USG, key, keylen, NULL);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to scan public point: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        return -1;
+    }
+
+    err = gcry_sexp_build(&ecdsa->key, NULL,
+        "(public-key (ecc (curve %s) (q %m)))", curve_name, q);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to build ECDSA public key: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+    ret = 0;
+
+cleanup:
+    gcry_mpi_release(q);
+    return ret;
+}
+
+static void qcrypto_gcrypt_ecdsa_free(QCryptoAkCipher *akcipher)
+{
+    QCryptoGcryptECDSA *ecdsa = (QCryptoGcryptECDSA *)akcipher;
+    if (!ecdsa) {
+        return;
+    }
+    gcry_sexp_release(ecdsa->key);
+    g_free(ecdsa);
+}
+
+static int qcrypto_gcrypt_invalid_encrypt(QCryptoAkCipher *akcipher,
+                                          const void *in, size_t in_len,
+                                          void *out, size_t out_len,
+                                          Error **errp)
+{
+    error_setg(errp, "Operation is invalid");
+    return -1;
+}
+
+static int qcrypto_gcrypt_invalid_decrypt(QCryptoAkCipher *akcipher,
+                                          const void *in, size_t in_len,
+                                          void *out, size_t out_len,
+                                          Error **errp)
+{
+    error_setg(errp, "Operation is invalid");
+    return -1;
+}
+
+static int qcrypto_gcrypt_ecdsa_sign(QCryptoAkCipher *akcipher,
+                                     const void *in, size_t in_len,
+                                     void *out, size_t out_len, Error **errp)
+{
+    QCryptoGcryptECDSA *ecdsa = (QCryptoGcryptECDSA *)akcipher;
+    int ret = -1;
+    gcry_mpi_t data = NULL, r_mpi = NULL, s_mpi = NULL;
+    gcry_sexp_t dgst_sexp = NULL, sig_sexp = NULL;
+    gcry_sexp_t r_sexp_item = NULL, s_sexp_item = NULL;
+    size_t actual_len;
+    gcry_error_t err;
+    g_autoptr(QCryptoAkCipherECDSASig) sig = NULL;
+
+    if (out_len < akcipher->max_signature_len) {
+        error_setg(errp, "Signature buffer should be not less than: %d",
+                   akcipher->max_signature_len);
+        return -1;
+    }
+    /*
+     * For ecdsa, digest length less than key length is recommended but not
+     * required, truncation occurs when digest is too long, see FIPS 186-4:
+     * https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf.
+     * Here we don't do the check, gcrypt will handle it.
+     */
+    err = gcry_mpi_scan(&data, GCRYMPI_FMT_USG, in, in_len, NULL);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to build data: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+
+    err = gcry_sexp_build(&dgst_sexp, NULL,
+                          "(data (flags raw) (value %m))", data);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to build dgst signature: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+
+    err = gcry_pk_sign(&sig_sexp, dgst_sexp, ecdsa->key);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to make signature: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+
+    sig = qcrypto_akcipher_ecdsasig_alloc(ecdsa->curve_id, errp);
+    if (!sig) {
+        goto cleanup;
+    }
+
+    /* S-expression of signature: (sig-val (ecdsa (r r-mpi) (s s-mpi))) */
+    r_sexp_item = gcry_sexp_find_token(sig_sexp, "r", 0);
+    if (!r_sexp_item || gcry_sexp_length(r_sexp_item) != 2) {
+        error_setg(errp, "Invalid signature result");
+        goto cleanup;
+    }
+    r_mpi = gcry_sexp_nth_mpi(r_sexp_item, 1, GCRYMPI_FMT_USG);
+    if (!r_mpi) {
+        error_setg(errp, "Invalid signature result");
+    }
+    err = gcry_mpi_print(GCRYMPI_FMT_STD, sig->r.data, sig->r.len,
+                         &actual_len, r_mpi);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to print MPI: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+    if (unlikely(actual_len > sig->r.len)) {
+        error_setg(errp, "Internal error: signature buffer is too small");
+        goto cleanup;
+    }
+    sig->r.len = actual_len;
+
+    s_sexp_item = gcry_sexp_find_token(sig_sexp, "s", 0);
+    if (!s_sexp_item || gcry_sexp_length(s_sexp_item) != 2) {
+        error_setg(errp, "Invalid signature result");
+        goto cleanup;
+    }
+    s_mpi = gcry_sexp_nth_mpi(s_sexp_item, 1, GCRYMPI_FMT_USG);
+    if (!s_mpi) {
+        error_setg(errp, "Invalid signature result");
+    }
+    err = gcry_mpi_print(GCRYMPI_FMT_STD, sig->s.data, sig->s.len,
+                         &actual_len, s_mpi);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to print MPI: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+    if (unlikely(actual_len > sig->s.len)) {
+        error_setg(errp, "Internal error: signature buffer is too small");
+        goto cleanup;
+    }
+    sig->s.len = actual_len;
+
+    qcrypto_akcipher_ecdsasig_x9_62_encode(sig, out, &out_len);
+    ret = out_len;
+
+cleanup:
+    gcry_mpi_release(data);
+    gcry_mpi_release(r_mpi);
+    gcry_mpi_release(s_mpi);
+    gcry_sexp_release(dgst_sexp);
+    gcry_sexp_release(sig_sexp);
+    gcry_sexp_release(r_sexp_item);
+
+    return ret;
+}
+
+static int qcrypto_gcrypt_ecdsa_verify(QCryptoAkCipher *akcipher,
+                                       const void *in, size_t in_len,
+                                       const void *in2, size_t in2_len,
+                                       Error **errp)
+{
+    QCryptoGcryptECDSA *ecdsa = (QCryptoGcryptECDSA *)akcipher;
+    int ret = -1;
+    QCryptoAkCipherECDSASig *sig;
+    gcry_mpi_t sig_s = NULL, sig_r = NULL, dgst_mpi = NULL;
+    gcry_sexp_t sig_sexp = NULL, dgst_sexp = NULL;
+    gcry_error_t err;
+
+    /*
+     * We only check the signature length, dgst length will be handled
+     * by gcrypt, see qcrypto_gcrypt_ecdsa_sign.
+     */
+    if (in_len > akcipher->max_signature_len) {
+        error_setg(errp, "Signature length is greater than %d",
+                   akcipher->max_signature_len);
+        return ret;
+    }
+
+    sig = qcrypto_akcipher_ecdsasig_parse(in, in_len, errp);
+    if (!sig) {
+        return ret;
+    }
+
+    err = gcry_mpi_scan(&sig_r, GCRYMPI_FMT_STD, sig->r.data, sig->r.len, NULL);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to parse ECDSA signature: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+    err = gcry_mpi_scan(&sig_s, GCRYMPI_FMT_STD, sig->s.data, sig->s.len, NULL);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to parse ECDSA signature: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+    err = gcry_sexp_build(&sig_sexp, NULL,
+                          "(sig-val (ecdsa (r %m) (s %m)))", sig_r, sig_s);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to build signature: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+
+    err = gcry_mpi_scan(&dgst_mpi, GCRYMPI_FMT_USG, in2, in2_len, NULL);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to parse scan mpi: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+    err = gcry_sexp_build(&dgst_sexp, NULL,
+                          "(data (flags raw) (value %m))", dgst_mpi);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to build dgst: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+
+    err = gcry_pk_verify(sig_sexp, dgst_sexp, ecdsa->key);
+    if (gcry_err_code(err) != 0) {
+        error_setg(errp, "Failed to verify signature: %s/%s",
+                   gcry_strsource(err), gcry_strerror(err));
+        goto cleanup;
+    }
+    ret = 0;
+
+cleanup:
+    gcry_mpi_release(sig_s);
+    gcry_mpi_release(sig_r);
+    gcry_mpi_release(dgst_mpi);
+    gcry_sexp_release(dgst_sexp);
+    gcry_sexp_release(sig_sexp);
+    qcrypto_akcipher_ecdsasig_free(sig);
+
+    return ret;
+}
+
+static QCryptoAkCipherDriver gcrypt_ecdsa = {
+    .encrypt = qcrypto_gcrypt_invalid_encrypt,
+    .decrypt = qcrypto_gcrypt_invalid_decrypt,
+    .sign = qcrypto_gcrypt_ecdsa_sign,
+    .verify = qcrypto_gcrypt_ecdsa_verify,
+    .free = qcrypto_gcrypt_ecdsa_free,
+};
+
+static QCryptoGcryptECDSA *qcrypto_gcrypt_ecdsa_new(
+    const QCryptoAkCipherOptionsECDSA *opts,
+    QCryptoAkCipherKeyType type,
+    const uint8_t *key, size_t keylen,
+    Error **errp)
+{
+    QCryptoGcryptECDSA *ecdsa = g_new0(QCryptoGcryptECDSA, 1);
+    if (qcrypto_gcrypt_parse_curve_id(ecdsa, opts, errp) != 0) {
+        goto error;
+    }
+    ecdsa->curve_id = opts->curve_id;
+    ecdsa->akcipher.driver = &gcrypt_ecdsa;
+
+    switch (type) {
+    case QCRYPTO_AKCIPHER_KEY_TYPE_PRIVATE:
+        if (qcrypto_gcrypt_parse_ecdsa_private_key(
+            ecdsa, ecdsa->curve_name, key, keylen, errp) != 0) {
+            goto error;
+        }
+        break;
+
+    case QCRYPTO_AKCIPHER_KEY_TYPE_PUBLIC:
+        if (qcrypto_gcrypt_parse_ecdsa_public_key(
+            ecdsa, ecdsa->curve_name, key, keylen, errp) != 0) {
+            goto error;
+        }
+        break;
+
+    default:
+        error_setg(errp, "Unknown akcipher key type %d", type);
+        goto error;
+    }
+
+    return ecdsa;
+
+error:
+    qcrypto_gcrypt_ecdsa_free((QCryptoAkCipher *)ecdsa);
+    return NULL;
+}
 
 bool qcrypto_akcipher_supports(QCryptoAkCipherOptions *opts)
 {
@@ -589,6 +978,17 @@  bool qcrypto_akcipher_supports(QCryptoAkCipherOptions *opts)
             return false;
         }
 
+    case QCRYPTO_AKCIPHER_ALG_ECDSA:
+        switch (opts->u.ecdsa.curve_id) {
+        case QCRYPTO_CURVE_ID_NIST_P192:
+        case QCRYPTO_CURVE_ID_NIST_P256:
+        case QCRYPTO_CURVE_ID_NIST_P384:
+            return true;
+
+        default:
+            return false;
+        }
+
     default:
         return true;
     }