1 files changed, 105 insertions, 0 deletions
diff --git a/drivers/auth/crypto_mod.c b/drivers/auth/crypto_mod.c
new file mode 100644
index 00000000..3b3e3ac4
--- /dev/null
+++ b/drivers/auth/crypto_mod.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <crypto_mod.h>
+#include <debug.h>
+
+/* Variable exported by the crypto library through REGISTER_CRYPTO_LIB() */
+extern const crypto_lib_desc_t crypto_lib_desc;
+
+/*
+ * The crypto module is responsible for verifying digital signatures and hashes.
+ * It relies on a crypto library to perform the cryptographic operations.
+ *
+ * The crypto module itself does not impose any specific format on signatures,
+ * signature algorithm, keys or hashes, but most cryptographic libraries will
+ * take the parameters as the following DER encoded ASN.1 structures:
+ *
+ *     AlgorithmIdentifier ::= SEQUENCE  {
+ *         algorithm        OBJECT IDENTIFIER,
+ *         parameters       ANY DEFINED BY algorithm OPTIONAL
+ *     }
+ *
+ *     DigestInfo ::= SEQUENCE {
+ *         digestAlgorithm  AlgorithmIdentifier,
+ *         digest           OCTET STRING
+ *     }
+ *
+ *     SubjectPublicKeyInfo ::= SEQUENCE  {
+ *         algorithm        AlgorithmIdentifier,
+ *         subjectPublicKey BIT STRING
+ *     }
+ *
+ *     SignatureAlgorithm ::= AlgorithmIdentifier
+ *
+ *     SignatureValue ::= BIT STRING
+ */
+
+/*
+ * Perform some static checking and call the library initialization function
+ */
+void crypto_mod_init(void)
+{
+	assert(crypto_lib_desc.name != NULL);
+	assert(crypto_lib_desc.init != NULL);
+	assert(crypto_lib_desc.verify_signature != NULL);
+	assert(crypto_lib_desc.verify_hash != NULL);
+
+	/* Initialize the cryptographic library */
+	crypto_lib_desc.init();
+	INFO("Using crypto library '%s'\n", crypto_lib_desc.name);
+}
+
+/*
+ * Function to verify a digital signature
+ *
+ * Parameters:
+ *
+ *   data_ptr, data_len: signed data
+ *   sig_ptr, sig_len: the digital signature
+ *   sig_alg_ptr, sig_alg_len: the digital signature algorithm
+ *   pk_ptr, pk_len: the public key
+ */
+int crypto_mod_verify_signature(void *data_ptr, unsigned int data_len,
+				void *sig_ptr, unsigned int sig_len,
+				void *sig_alg_ptr, unsigned int sig_alg_len,
+				void *pk_ptr, unsigned int pk_len)
+{
+	assert(data_ptr != NULL);
+	assert(data_len != 0);
+	assert(sig_ptr != NULL);
+	assert(sig_len != 0);
+	assert(sig_alg_ptr != NULL);
+	assert(sig_alg_len != 0);
+	assert(pk_ptr != NULL);
+	assert(pk_len != 0);
+
+	return crypto_lib_desc.verify_signature(data_ptr, data_len,
+						sig_ptr, sig_len,
+						sig_alg_ptr, sig_alg_len,
+						pk_ptr, pk_len);
+}
+
+/*
+ * Verify a hash by comparison
+ *
+ * Parameters:
+ *
+ *   data_ptr, data_len: data to be hashed
+ *   digest_info_ptr, digest_info_len: hash to be compared
+ */
+int crypto_mod_verify_hash(void *data_ptr, unsigned int data_len,
+			   void *digest_info_ptr, unsigned int digest_info_len)
+{
+	assert(data_ptr != NULL);
+	assert(data_len != 0);
+	assert(digest_info_ptr != NULL);
+	assert(digest_info_len != 0);
+
+	return crypto_lib_desc.verify_hash(data_ptr, data_len,
+					   digest_info_ptr, digest_info_len);
+}