1 files changed, 80 insertions, 0 deletions
diff --git a/firmware/2lib/2packed_key.c b/firmware/2lib/2packed_key.c
new file mode 100644
index 00000000..4e2c654a
--- /dev/null
+++ b/firmware/2lib/2packed_key.c
@@ -0,0 +1,80 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Key unpacking functions
+ */
+
+#include "2common.h"
+#include "2packed_key.h"
+#include "2rsa.h"
+#include "2sysincludes.h"
+
+test_mockable
+vb2_error_t vb2_unpack_key_buffer(struct vb2_public_key *key,
+				  const uint8_t *buf, uint32_t size)
+{
+	const struct vb2_packed_key *packed_key =
+		(const struct vb2_packed_key *)buf;
+	const uint32_t *buf32;
+	uint32_t expected_key_size;
+
+	/* Make sure passed buffer is big enough for the packed key */
+	VB2_TRY(vb2_verify_packed_key_inside(buf, size, packed_key));
+
+	/* Unpack key algorithm */
+	key->sig_alg = vb2_crypto_to_signature(packed_key->algorithm);
+	if (key->sig_alg == VB2_SIG_INVALID) {
+		VB2_DEBUG("Unsupported signature algorithm.\n");
+		return VB2_ERROR_UNPACK_KEY_SIG_ALGORITHM;
+	}
+
+	key->hash_alg = vb2_crypto_to_hash(packed_key->algorithm);
+	if (key->hash_alg == VB2_HASH_INVALID) {
+		VB2_DEBUG("Unsupported hash algorithm.\n");
+		return VB2_ERROR_UNPACK_KEY_HASH_ALGORITHM;
+	}
+
+	expected_key_size = vb2_packed_key_size(key->sig_alg);
+	if (!expected_key_size || expected_key_size != packed_key->key_size) {
+		VB2_DEBUG("Wrong key size for algorithm\n");
+		return VB2_ERROR_UNPACK_KEY_SIZE;
+	}
+
+	/* Make sure source buffer is 32-bit aligned */
+	buf32 = (const uint32_t *)vb2_packed_key_data(packed_key);
+	if (!vb2_aligned(buf32, sizeof(uint32_t)))
+		return VB2_ERROR_UNPACK_KEY_ALIGN;
+
+	/* Validity check key array size */
+	key->arrsize = buf32[0];
+	if (key->arrsize * sizeof(uint32_t) != vb2_rsa_sig_size(key->sig_alg))
+		return VB2_ERROR_UNPACK_KEY_ARRAY_SIZE;
+
+	key->n0inv = buf32[1];
+
+	/* Arrays point inside the key data */
+	key->n = buf32 + 2;
+	key->rr = buf32 + 2 + key->arrsize;
+
+	/* disable hwcrypto for RSA by default */
+	key->allow_hwcrypto = 0;
+
+#ifdef __COVERITY__
+	__coverity_tainted_data_sanitize__(key);
+	__coverity_tainted_data_sanitize__(buf);
+#endif
+	return VB2_SUCCESS;
+}
+
+vb2_error_t vb2_unpack_key(struct vb2_public_key *key,
+			   const struct vb2_packed_key *packed_key)
+{
+	if (!packed_key)
+		return VB2_ERROR_UNPACK_KEY_BUFFER;
+
+	return vb2_unpack_key_buffer(key,
+				     (const uint8_t *)packed_key,
+				     packed_key->key_offset +
+				     packed_key->key_size);
+}