Commit 928a8be7 authored by Alexandru Gagniuc's avatar Alexandru Gagniuc Committed by Patrice Chotard
Browse files

lib: ecdsa: Implement UCLASS_ECDSA verification on target



Implement the crypto_algo .verify() function for ecdsa256. Because
it backends on UCLASS_ECDSA, this change is focused on parsing the
keys from devicetree and passing this information to the specific
UCLASS driver.
Signed-off-by: default avatarAlexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-by: Simon Glass's avatarSimon Glass <sjg@chromium.org>
Reviewed-by: Patrick Delaunay's avatarPatrick Delaunay <patrick.delaunay@foss.st.com>
parent 1d54af13
......@@ -303,6 +303,7 @@ config AES
supported by the algorithm but only a 128-bit key is supported at
present.
source lib/ecdsa/Kconfig
source lib/rsa/Kconfig
source lib/crypto/Kconfig
source lib/crypt/Kconfig
......
......@@ -60,6 +60,7 @@ endif
obj-$(CONFIG_$(SPL_)ACPIGEN) += acpi/
obj-$(CONFIG_$(SPL_)MD5) += md5.o
obj-$(CONFIG_ECDSA) += ecdsa/
obj-$(CONFIG_$(SPL_)RSA) += rsa/
obj-$(CONFIG_HASH) += hash-checksum.o
obj-$(CONFIG_SHA1) += sha1.o
......
config ECDSA
bool "Enable ECDSA support"
depends on DM
help
This enables the ECDSA (elliptic curve signature) algorithm for FIT
image verification in U-Boot. The ECDSA algorithm is implemented
using the driver model, so CONFIG_DM is required by this library.
See doc/uImage.FIT/signature.txt for more details.
ECDSA is enabled for mkimage regardless of this option.
if ECDSA
config ECDSA_VERIFY
bool "Enable ECDSA verification support in U-Boot."
help
Allow ECDSA signatures to be recognized and verified in U-Boot.
config SPL_ECDSA_VERIFY
bool "Enable ECDSA verification support in SPL"
help
Allow ECDSA signatures to be recognized and verified in SPL.
endif
obj-$(CONFIG_$(SPL_)ECDSA_VERIFY) += ecdsa-verify.o
// SPDX-License-Identifier: GPL-2.0+
/*
* ECDSA signature verification for u-boot
*
* This implements the firmware-side wrapper for ECDSA verification. It bridges
* the struct crypto_algo API to the ECDSA uclass implementations.
*
* Copyright (c) 2020, Alexandru Gagniuc <mr.nuke.me@gmail.com>
*/
#include <crypto/ecdsa-uclass.h>
#include <dm/uclass.h>
#include <u-boot/ecdsa.h>
/*
* Derive size of an ECDSA key from the curve name
*
* While it's possible to extract the key size by using string manipulation,
* use a list of known curves for the time being.
*/
static int ecdsa_key_size(const char *curve_name)
{
if (!strcmp(curve_name, "prime256v1"))
return 256;
else
return 0;
}
static int fdt_get_key(struct ecdsa_public_key *key, const void *fdt, int node)
{
int x_len, y_len;
key->curve_name = fdt_getprop(fdt, node, "ecdsa,curve", NULL);
key->size_bits = ecdsa_key_size(key->curve_name);
if (key->size_bits == 0) {
debug("Unknown ECDSA curve '%s'", key->curve_name);
return -EINVAL;
}
key->x = fdt_getprop(fdt, node, "ecdsa,x-point", &x_len);
key->y = fdt_getprop(fdt, node, "ecdsa,y-point", &y_len);
if (!key->x || !key->y)
return -EINVAL;
if (x_len != (key->size_bits / 8) || y_len != (key->size_bits / 8)) {
printf("%s: node=%d, curve@%p x@%p+%i y@%p+%i\n", __func__,
node, key->curve_name, key->x, x_len, key->y, y_len);
return -EINVAL;
}
return 0;
}
static int ecdsa_verify_hash(struct udevice *dev,
const struct image_sign_info *info,
const void *hash, const void *sig, uint sig_len)
{
const struct ecdsa_ops *ops = device_get_ops(dev);
const struct checksum_algo *algo = info->checksum;
struct ecdsa_public_key key;
int sig_node, key_node, ret;
if (!ops || !ops->verify)
return -ENODEV;
if (info->required_keynode > 0) {
ret = fdt_get_key(&key, info->fdt_blob, info->required_keynode);
if (ret < 0)
return ret;
return ops->verify(dev, &key, hash, algo->checksum_len,
sig, sig_len);
}
sig_node = fdt_subnode_offset(info->fdt_blob, 0, FIT_SIG_NODENAME);
if (sig_node < 0)
return -ENOENT;
/* Try all possible keys under the "/signature" node */
fdt_for_each_subnode(key_node, info->fdt_blob, sig_node) {
ret = fdt_get_key(&key, info->fdt_blob, key_node);
if (ret < 0)
continue;
ret = ops->verify(dev, &key, hash, algo->checksum_len,
sig, sig_len);
/* On success, don't worry about remaining keys */
if (!ret)
return 0;
}
return -EPERM;
}
int ecdsa_verify(struct image_sign_info *info,
const struct image_region region[], int region_count,
uint8_t *sig, uint sig_len)
{
const struct checksum_algo *algo = info->checksum;
uint8_t hash[algo->checksum_len];
struct udevice *dev;
int ret;
ret = uclass_first_device_err(UCLASS_ECDSA, &dev);
if (ret) {
debug("ECDSA: Could not find ECDSA implementation: %d\n", ret);
return ret;
}
ret = algo->calculate(algo->name, region, region_count, hash);
if (ret < 0)
return -EINVAL;
return ecdsa_verify_hash(dev, info, hash, sig, sig_len);
}
U_BOOT_CRYPTO_ALGO(ecdsa) = {
.name = "ecdsa256",
.key_len = ECDSA256_BYTES,
.verify = ecdsa_verify,
};
/*
* uclass definition for ECDSA API
*
* We don't implement any wrappers around ecdsa_ops->verify() because it's
* trivial to call ops->verify().
*/
UCLASS_DRIVER(ecdsa) = {
.id = UCLASS_ECDSA,
.name = "ecdsa_verifier",
};
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