Bluetooth: Host: SMP: Verify public key before usage (880384a2) · Commits · Wenxi XU / zephyr

subsys/bluetooth/host/ecc.c

+32 −0

Changes for subsys/bluetooth/host/ecc.c: 32 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		@@ -7,9 +7,12 @@

		#include <stdint.h>

		#include <zephyr/sys/byteorder.h>
		#include <zephyr/sys/check.h>
		#include <zephyr/bluetooth/hci.h>

		#include <psa/crypto.h>

		#include "ecc.h"
		#include "hci_core.h"

		@@ -39,6 +42,35 @@ bool bt_pub_key_is_debug(uint8_t *cmp_pub_key)
		return memcmp(cmp_pub_key, debug_public_key, BT_PUB_KEY_LEN) == 0;
		}

		bool bt_pub_key_is_valid(const uint8_t key[BT_PUB_KEY_LEN])
		{
		uint8_t key_be[BT_PUB_KEY_LEN + 1];
		psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
		psa_status_t ret;
		psa_key_id_t handle;

		psa_set_key_type(&attr, PSA_KEY_TYPE_ECC_PUBLIC_KEY(PSA_ECC_FAMILY_SECP_R1));
		psa_set_key_bits(&attr, 256);
		psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_DERIVE);
		psa_set_key_algorithm(&attr, PSA_ALG_ECDH);

		/* PSA expects secp256r1 public key to start with a predefined 0x04 byte */
		key_be[0] = 0x04;
		sys_memcpy_swap(&key_be[1], key, BT_PUB_KEY_COORD_LEN);
		sys_memcpy_swap(&key_be[1 + BT_PUB_KEY_COORD_LEN], &key[BT_PUB_KEY_COORD_LEN],
		BT_PUB_KEY_COORD_LEN);

		ret = psa_import_key(&attr, key_be, sizeof(key_be), &handle);
		psa_reset_key_attributes(&attr);

		if (ret == PSA_SUCCESS) {
		psa_destroy_key(handle);
		return true;
		}

		return false;
		}

		int bt_pub_key_gen(struct bt_pub_key_cb *new_cb)
		{
		struct bt_pub_key_cb *cb;

+10 −0

Changes for subsys/bluetooth/host/ecc.h: 10 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		@@ -44,6 +44,16 @@ struct bt_pub_key_cb {
		*/
		bool bt_pub_key_is_debug(uint8_t *cmp_pub_key);

		/* @brief Check if public key is valid.
		*
		* Verify that the public key is valid, e.g. that its coordinates lie on the eliptic curve.
		*
		* @param key The public key to validate.
		*
		* @return True if the public key is valid.
		*/
		bool bt_pub_key_is_valid(const uint8_t key[BT_PUB_KEY_LEN]);

		/* @brief Generate a new Public Key.
		*
		* Generate a new ECC Public Key. Provided cb must persists until callback

+3 −0

Changes for subsys/bluetooth/host/smp.c: 3 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		@@ -4311,6 +4311,9 @@ static uint8_t smp_public_key(struct bt_smp smp, struct net_buf buf)
		if (!update_debug_keys_check(smp)) {
		return BT_SMP_ERR_AUTH_REQUIREMENTS;
		}
		} else if (!bt_pub_key_is_valid(smp->pkey)) {
		LOG_WRN("Received invalid public key");
		return BT_SMP_ERR_INVALID_PARAMS;
		}

		if (IS_ENABLED(CONFIG_BT_CENTRAL) &&