[PATCH v4 1/6] dm: crypto: Define UCLASS API for ECDSA signature verification

Alexandru Gagniuc
2021-04-15T20:05:04Z

Define a UCLASS API for verifying ECDSA signatures. Unlike
UCLASS_MOD_EXP, which focuses strictly on modular exponentiation,
the ECDSA class focuses on verification. This is done so that it
better aligns with mach-specific implementations, such as stm32mp.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
---
include/crypto/ecdsa-uclass.h | 39 +++++++++++++++++++++++++++++++++++
include/dm/uclass-id.h | 1 +
2 files changed, 40 insertions(+)
create mode 100644 include/crypto/ecdsa-uclass.h

diff --git a/include/crypto/ecdsa-uclass.h b/include/crypto/ecdsa-uclass.h
new file mode 100644
index 0000000000..189843820a
--- /dev/null
+++ b/include/crypto/ecdsa-uclass.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2020, Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ */
+
+#include <dm/device.h>
+
+/**
+ * struct ecdsa_public_key - ECDSA public key properties
+ *
+ * The struct has pointers to the (x, y) curve coordinates to an ECDSA public
+ * key, as well as the name of the ECDSA curve. The size of the key is inferred
+ * from the 'curve_name'
+ */
+struct ecdsa_public_key {
+ const char *curve_name; /* Name of curve, e.g. "prime256v1" */
+ const void *x; /* x coordinate of public key */
+ const void *y; /* y coordinate of public key */
+ unsigned int size_bits; /* key size in bits, derived from curve name */
+};
+
+struct ecdsa_ops {
+ /**
+ * Verify signature of hash against given public key
+ *
+ * @dev: ECDSA Device
+ * @pubkey: ECDSA public key
+ * @hash: Hash of binary image
+ * @hash_len: Length of hash in bytes
+ * @signature: Signature in a raw (R, S) point pair
+ * @sig_len: Length of signature in bytes
+ *
+ * This function verifies that the 'signature' of the given 'hash' was
+ * signed by the private key corresponding to 'pubkey'.
+ */
+ int (*verify)(struct udevice *dev, const struct ecdsa_public_key *pubkey,
+ const void *hash, size_t hash_len,
+ const void *signature, size_t sig_len);
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index d800f679d5..2a32809669 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -47,6 +47,7 @@ enum uclass_id {
UCLASS_DSI_HOST, /* Display Serial Interface host */
UCLASS_DMA, /* Direct Memory Access */
UCLASS_DSA, /* Distributed (Ethernet) Switch Architecture */
+ UCLASS_ECDSA, /* Elliptic curve cryptographic device */
UCLASS_EFI, /* EFI managed devices */
UCLASS_ETH, /* Ethernet device */
UCLASS_ETH_PHY, /* Ethernet PHY device */
--
2.26.3