[PATCH v8 08/30] crypto/x509-utils: Add helper functions for DIAG 320 subcode 2

[Zhuoying Cai <zycai@linux.ibm.com>]

Introduce new helper functions to extract certificate metadata:

qcrypto_x509_check_cert_times() - validates the certificate's validity period against the current time
qcrypto_x509_get_pk_algorithm() - returns the public key algorithm used in the certificate
qcrypto_x509_get_cert_key_id() - extracts the key ID from the certificate
qcrypto_x509_check_ecc_curve_p521() - determines the ECC public key algorithm uses P-521 curve

These functions provide support for metadata extraction and validity checking
for X.509 certificates.

Signed-off-by: Zhuoying Cai <zycai@linux.ibm.com>
Reviewed-by: Farhan Ali<alifm@linux.ibm.com>
---
 crypto/x509-utils.c         | 236 ++++++++++++++++++++++++++++++++++++
 include/crypto/x509-utils.h |  51 ++++++++
 2 files changed, 287 insertions(+)

diff --git a/crypto/x509-utils.c b/crypto/x509-utils.c
index 2696d48155..906d5e5e87 100644
--- a/crypto/x509-utils.c
+++ b/crypto/x509-utils.c
@@ -27,6 +27,16 @@ static const int qcrypto_to_gnutls_hash_alg_map[QCRYPTO_HASH_ALGO__MAX] = {
     [QCRYPTO_HASH_ALGO_RIPEMD160] = GNUTLS_DIG_RMD160,
 };
 
+static const int qcrypto_to_gnutls_keyid_flags_map[] = {
+    [QCRYPTO_HASH_ALGO_MD5] = -1,
+    [QCRYPTO_HASH_ALGO_SHA1] = GNUTLS_KEYID_USE_SHA1,
+    [QCRYPTO_HASH_ALGO_SHA224] = -1,
+    [QCRYPTO_HASH_ALGO_SHA256] = GNUTLS_KEYID_USE_SHA256,
+    [QCRYPTO_HASH_ALGO_SHA384] = -1,
+    [QCRYPTO_HASH_ALGO_SHA512] = GNUTLS_KEYID_USE_SHA512,
+    [QCRYPTO_HASH_ALGO_RIPEMD160] = -1,
+};
+
 int qcrypto_get_x509_cert_fingerprint(uint8_t *cert, size_t size,
                                       QCryptoHashAlgo alg,
                                       uint8_t *result,
@@ -121,6 +131,210 @@ cleanup:
     return ret;
 }
 
+int qcrypto_x509_check_cert_times(uint8_t *cert, size_t size, Error **errp)
+{
+    int rc;
+    int ret = -1;
+    gnutls_x509_crt_t crt;
+    gnutls_datum_t datum = {.data = cert, .size = size};
+    time_t now = time(NULL);
+    time_t exp_time;
+    time_t act_time;
+
+    if (now == ((time_t)-1)) {
+        error_setg_errno(errp, errno, "Cannot get current time");
+        return ret;
+    }
+
+    rc = gnutls_x509_crt_init(&crt);
+    if (rc < 0) {
+        error_setg(errp, "Failed to initialize certificate: %s", gnutls_strerror(rc));
+        return ret;
+    }
+
+    rc = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM);
+    if (rc != 0) {
+        error_setg(errp, "Failed to import certificate: %s", gnutls_strerror(rc));
+        goto cleanup;
+    }
+
+    exp_time = gnutls_x509_crt_get_expiration_time(crt);
+    if (exp_time == ((time_t)-1)) {
+        error_setg(errp, "Failed to get certificate expiration time");
+        goto cleanup;
+    }
+    if (exp_time < now) {
+        error_setg(errp, "The certificate has expired");
+        goto cleanup;
+    }
+
+    act_time = gnutls_x509_crt_get_activation_time(crt);
+    if (act_time == ((time_t)-1)) {
+        error_setg(errp, "Failed to get certificate activation time");
+        goto cleanup;
+    }
+    if (act_time > now) {
+        error_setg(errp, "The certificate is not yet active");
+        goto cleanup;
+    }
+
+    ret = 0;
+
+cleanup:
+    gnutls_x509_crt_deinit(crt);
+    return ret;
+}
+
+static int qcrypto_x509_get_pk_algorithm(uint8_t *cert, size_t size, Error **errp)
+{
+    int rc;
+    int ret = -1;
+    unsigned int bits;
+    gnutls_x509_crt_t crt;
+    gnutls_datum_t datum = {.data = cert, .size = size};
+
+    rc = gnutls_x509_crt_init(&crt);
+    if (rc < 0) {
+        error_setg(errp, "Failed to initialize certificate: %s", gnutls_strerror(rc));
+        return ret;
+    }
+
+    rc = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM);
+    if (rc != 0) {
+        error_setg(errp, "Failed to import certificate: %s", gnutls_strerror(rc));
+        goto cleanup;
+    }
+
+    rc = gnutls_x509_crt_get_pk_algorithm(crt, &bits);
+    if (rc < 0) {
+        error_setg(errp, "Unknown public key algorithm %d", rc);
+        goto cleanup;
+    }
+
+    ret = rc;
+
+cleanup:
+    gnutls_x509_crt_deinit(crt);
+    return ret;
+}
+
+int qcrypto_x509_get_cert_key_id(uint8_t *cert, size_t size,
+                                 QCryptoHashAlgo hash_alg,
+                                 uint8_t **result,
+                                 size_t *resultlen,
+                                 Error **errp)
+{
+    int rc;
+    int ret = -1;
+    gnutls_x509_crt_t crt;
+    gnutls_datum_t datum = {.data = cert, .size = size};
+
+    if (hash_alg >= G_N_ELEMENTS(qcrypto_to_gnutls_hash_alg_map)) {
+        error_setg(errp, "Unknown hash algorithm %d", hash_alg);
+        return ret;
+    }
+
+    if (hash_alg >= G_N_ELEMENTS(qcrypto_to_gnutls_keyid_flags_map) ||
+        qcrypto_to_gnutls_keyid_flags_map[hash_alg] == -1) {
+        error_setg(errp, "Unsupported key id flag %d", hash_alg);
+        return ret;
+    }
+
+    rc = gnutls_x509_crt_init(&crt);
+    if (rc < 0) {
+        error_setg(errp, "Failed to initialize certificate: %s", gnutls_strerror(rc));
+        return ret;
+    }
+
+    rc = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM);
+    if (rc != 0) {
+        error_setg(errp, "Failed to import certificate: %s", gnutls_strerror(rc));
+        goto cleanup;
+    }
+
+    *resultlen = gnutls_hash_get_len(qcrypto_to_gnutls_hash_alg_map[hash_alg]);
+    if (*resultlen == 0) {
+        error_setg(errp, "Failed to get hash algorithn length: %s", gnutls_strerror(rc));
+        goto cleanup;
+    }
+
+    *result = g_malloc0(*resultlen);
+    if (gnutls_x509_crt_get_key_id(crt,
+                                   qcrypto_to_gnutls_keyid_flags_map[hash_alg],
+                                   *result, resultlen) != 0) {
+        error_setg(errp, "Failed to get key ID from certificate");
+        g_clear_pointer(result, g_free);
+        goto cleanup;
+    }
+
+    ret = 0;
+
+cleanup:
+    gnutls_x509_crt_deinit(crt);
+    return ret;
+}
+
+static int qcrypto_x509_get_ecc_curve(uint8_t *cert, size_t size, Error **errp)
+{
+    int rc;
+    int ret = -1;
+    gnutls_x509_crt_t crt;
+    gnutls_datum_t datum = {.data = cert, .size = size};
+    gnutls_ecc_curve_t curve_id;
+    gnutls_datum_t x = {.data = NULL, .size = 0};
+    gnutls_datum_t y = {.data = NULL, .size = 0};
+
+    rc = gnutls_x509_crt_init(&crt);
+    if (rc < 0) {
+        error_setg(errp, "Failed to initialize certificate: %s", gnutls_strerror(rc));
+        return ret;
+    }
+
+    rc = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM);
+    if (rc != 0) {
+        error_setg(errp, "Failed to import certificate: %s", gnutls_strerror(rc));
+        goto cleanup;
+    }
+
+    rc = gnutls_x509_crt_get_pk_ecc_raw(crt, &curve_id, &x, &y);
+    if (rc != 0) {
+        error_setg(errp, "Failed to get ECC public key curve: %s", gnutls_strerror(rc));
+        goto cleanup;
+    }
+
+    ret = curve_id;
+
+cleanup:
+    gnutls_x509_crt_deinit(crt);
+    gnutls_free(x.data);
+    gnutls_free(y.data);
+    return ret;
+}
+
+int qcrypto_x509_check_ecc_curve_p521(uint8_t *cert, size_t size, Error **errp)
+{
+    int algo;
+    int curve_id;
+
+    algo = qcrypto_x509_get_pk_algorithm(cert, size, errp);
+    if (algo != GNUTLS_PK_ECDSA) {
+        return 0;
+    }
+
+    curve_id = qcrypto_x509_get_ecc_curve(cert, size, errp);
+    if (curve_id == -1) {
+        error_setg(errp, "Failed to get ECC curve");
+        return -1;
+    }
+
+    if (curve_id == GNUTLS_ECC_CURVE_INVALID) {
+        error_setg(errp, "Invalid ECC curve");
+        return -1;
+    }
+
+    return curve_id == GNUTLS_ECC_CURVE_SECP521R1;
+}
+
 #else /* ! CONFIG_GNUTLS */
 
 int qcrypto_get_x509_cert_fingerprint(uint8_t *cert, size_t size,
@@ -142,4 +356,26 @@ int qcrypto_x509_convert_cert_der(uint8_t *cert, size_t size,
     return -1;
 }
 
+int qcrypto_x509_check_cert_times(uint8_t *cert, size_t size, Error **errp)
+{
+    error_setg(errp, "GNUTLS is required to get certificate times");
+    return -1;
+}
+
+int qcrypto_x509_get_cert_key_id(uint8_t *cert, size_t size,
+                                 QCryptoHashAlgo hash_alg,
+                                 uint8_t **result,
+                                 size_t *resultlen,
+                                 Error **errp)
+{
+    error_setg(errp, "GNUTLS is required to get key ID");
+    return -1;
+}
+
+int qcrypto_x509_check_ecc_curve_p521(uint8_t *cert, size_t size, Error **errp)
+{
+    error_setg(errp, "GNUTLS is required to determine ecc curve");
+    return -1;
+}
+
 #endif /* ! CONFIG_GNUTLS */
diff --git a/include/crypto/x509-utils.h b/include/crypto/x509-utils.h
index 91ae79fb03..6040894a46 100644
--- a/include/crypto/x509-utils.h
+++ b/include/crypto/x509-utils.h
@@ -40,4 +40,55 @@ int qcrypto_x509_convert_cert_der(uint8_t *cert, size_t size,
                                   size_t *resultlen,
                                   Error **errp);
 
+/**
+ * qcrypto_x509_check_cert_times
+ * @cert: pointer to the raw certificate data
+ * @size: size of the certificate
+ * @errp: error pointer
+ *
+ * Check whether the activation and expiration times of @cert
+ * are valid at the current time.
+ *
+ * Returns: 0 if the certificate times are valid,
+ *         -1 on error.
+ */
+int qcrypto_x509_check_cert_times(uint8_t *cert, size_t size, Error **errp);
+
+/**
+ * qcrypto_x509_get_cert_key_id
+ * @cert: pointer to the raw certificate data
+ * @size: size of the certificate
+ * @hash_alg: the hash algorithm flag
+ * @result: output location for the allocated buffer for key ID
+ *          (the function allocates memory which must be freed by the caller)
+ * @resultlen: pointer to the size of the buffer
+ *             (will be updated with the actual size of key id)
+ * @errp: error pointer
+ *
+ * Retrieve the key ID from the @cert based on the specified @flag.
+ *
+ * Returns: 0 if key ID was successfully stored in @result,
+ *         -1 on error.
+ */
+int qcrypto_x509_get_cert_key_id(uint8_t *cert, size_t size,
+                                 QCryptoHashAlgo hash_alg,
+                                 uint8_t **result,
+                                 size_t *resultlen,
+                                 Error **errp);
+
+/**
+ * qcrypto_x509_check_ecc_curve_p521
+ * @cert: pointer to the raw certificate data
+ * @size: size of the certificate
+ * @errp: error pointer
+ *
+ * Determine whether the ECC public key in the given certificate uses the P-521
+ * curve.
+ *
+ * Returns: 0 if ECC public key does not use P521 curve.
+ *          1 if ECC public key uses P521 curve.
+ *         -1 on error.
+ */
+int qcrypto_x509_check_ecc_curve_p521(uint8_t *cert, size_t size, Error **errp);
+
 #endif
-- 
2.52.0