Implementation of the Cryptnox secure channel protocol. More...

#include "CW_SecureChannel.h"
#include "CW_Utils.h"
#include "CW_TrustedKeys.h"

Include dependency graph for CW_SecureChannel.cpp:

Macros
#define	RESPONSE_GETCARDCERTIFICATE_IN_BYTES 148U
#define	RESPONSE_SELECT_IN_BYTES 40U
#define	RESPONSE_GETMANUFACTURERCERT_PAGE_IN_BYTES 420U
#define	RESPONSE_OPENSECURECHANNEL_IN_BYTES 34U
#define	REQUEST_MUTUALLYAUTHENTICATE_IN_BYTES 69U
#define	RESPONSE_MUTUALLYAUTHENTICATE_IN_BYTES 66U
#define	RESPONSE_STATUS_WORDS_IN_BYTES 2U
#define	OPENSECURECHANNEL_SALT_IN_BYTES (RESPONSE_OPENSECURECHANNEL_IN_BYTES - RESPONSE_STATUS_WORDS_IN_BYTES)
#define	GETCARDCERTIFICATE_IN_BYTES (RESPONSE_GETCARDCERTIFICATE_IN_BYTES - RESPONSE_STATUS_WORDS_IN_BYTES)
#define	RANDOM_BYTES 8U
#define	COMMON_PAIRING_DATA CW_PAIRING_DATA
#define	CLIENT_PRIVATE_KEY_SIZE 32U
#define	CLIENT_PUBLIC_KEY_SIZE 64U
#define	CARDEPHEMERALPUBKEY_SIZE 64U
#define	AES_BLOCK_SIZE 16U
#define	APDU_HEADER_LEN (4U)
#define	APDU_LC_LEN (1U)
#define	MAC_APDU_LEN (12U)
#define	INPUT_BUFFER_LIMIT (CW_USER_DATA_PAGE_SIZE)
#define	ENC_BUF_MAX_LEN (INPUT_BUFFER_LIMIT + AES_BLOCK_SIZE)
#define	MAX_MAC_DATA_LEN (APDU_HEADER_LEN + MAC_APDU_LEN + ENC_BUF_MAX_LEN)
#define	SEND_APDU_MAX_LEN (APDU_HEADER_LEN + APDU_LC_LEN + AES_BLOCK_SIZE + ENC_BUF_MAX_LEN)
#define	DER_TAG_SEQUENCE (0x30U) /* SEQUENCE (universal, constructed) */
#define	DER_TAG_BIT_STRING (0x03U) /* BIT STRING */
#define	DER_TAG_CTX0 (0xA0U) /* [0] EXPLICIT — version in v3 TBSCertificate */
#define	DER_LEN_LONG_FLAG (0x80U) /* set = long-form length */
#define	DER_LEN_LONG_1 (0x81U) /* long form, 1 following byte */
#define	DER_LEN_LONG_2 (0x82U) /* long form, 2 following bytes */
#define	DER_EC_UNCOMPRESSED (0x04U) /* uncompressed point prefix */
#define	DER_EC_POINT_BYTES (65U) /* 0x04 \|\| X[32] \|\| Y[32] */
#define	DER_BIT_UNUSED_ZERO (0x00U) /* BIT STRING unused-bits field must be 0 */

Functions
static bool	derReadLength (const uint8_t *buf, uint16_t bufLen, uint16_t &pos, uint16_t &fieldLen)
static bool	derSkipField (const uint8_t *buf, uint16_t bufLen, uint16_t &pos)
static bool	derWalkMfCert (const uint8_t buf, uint16_t bufLen, uint16_t &tbsMsgStart, uint16_t &tbsMsgLen, const uint8_t &pubKey65Ptr, const uint8_t *&sigPtr, uint8_t &sigLen)

Variables
static uint8_t	s_apduBuf [SEND_APDU_MAX_LEN]
static uint8_t	s_macBuf [MAX_MAC_DATA_LEN]
static uint8_t	s_dataBuf [ENC_BUF_MAX_LEN]
static uint8_t	s_mfCertBuf [CW_MANUF_CERT_MAX_BYTES]

Detailed Description

Implementation of the Cryptnox secure channel protocol.

Implements the methods declared in CW_SecureChannel.h: APDU framing, certificate chain verification against the trusted CA keys (CW_TrustedKeys.h), ECDH session key derivation, AES-CBC encrypted messaging with rolling IV, and MAC verification on every response.

Module-level static scratch buffers are reused across calls to keep the stack footprint small; secret material is wiped after use.

Definition in file CW_SecureChannel.cpp.

Macro Definition Documentation

◆ AES_BLOCK_SIZE

#define AES_BLOCK_SIZE 16U

Definition at line 45 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcDecrypt(), CW_SecureChannel::aesCbcEncrypt(), and CW_SecureChannel::mutuallyAuthenticate().

◆ APDU_HEADER_LEN

#define APDU_HEADER_LEN (4U)

Definition at line 46 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::mutuallyAuthenticate().

◆ APDU_LC_LEN

#define APDU_LC_LEN (1U)

Definition at line 47 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcEncrypt(), and CW_SecureChannel::mutuallyAuthenticate().

◆ CARDEPHEMERALPUBKEY_SIZE

#define CARDEPHEMERALPUBKEY_SIZE 64U

Definition at line 44 of file CW_SecureChannel.cpp.

◆ CLIENT_PRIVATE_KEY_SIZE

#define CLIENT_PRIVATE_KEY_SIZE 32U

Definition at line 42 of file CW_SecureChannel.cpp.

◆ CLIENT_PUBLIC_KEY_SIZE

#define CLIENT_PUBLIC_KEY_SIZE 64U

Definition at line 43 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::openSecureChannel().

◆ COMMON_PAIRING_DATA

#define COMMON_PAIRING_DATA CW_PAIRING_DATA

Definition at line 41 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::mutuallyAuthenticate().

◆ DER_BIT_UNUSED_ZERO

#define DER_BIT_UNUSED_ZERO (0x00U) /* BIT STRING unused-bits field must be 0 */

Definition at line 80 of file CW_SecureChannel.cpp.

Referenced by derWalkMfCert().

◆ DER_EC_POINT_BYTES

#define DER_EC_POINT_BYTES (65U) /* 0x04 || X[32] || Y[32] */

Definition at line 79 of file CW_SecureChannel.cpp.

Referenced by derWalkMfCert().

◆ DER_EC_UNCOMPRESSED

#define DER_EC_UNCOMPRESSED (0x04U) /* uncompressed point prefix */

Definition at line 78 of file CW_SecureChannel.cpp.

Referenced by derWalkMfCert().

◆ DER_LEN_LONG_1

#define DER_LEN_LONG_1 (0x81U) /* long form, 1 following byte */

Definition at line 74 of file CW_SecureChannel.cpp.

Referenced by derReadLength().

◆ DER_LEN_LONG_2

#define DER_LEN_LONG_2 (0x82U) /* long form, 2 following bytes */

Definition at line 75 of file CW_SecureChannel.cpp.

Referenced by derReadLength().

◆ DER_LEN_LONG_FLAG

#define DER_LEN_LONG_FLAG (0x80U) /* set = long-form length */

Definition at line 73 of file CW_SecureChannel.cpp.

Referenced by derReadLength().

◆ DER_TAG_BIT_STRING

#define DER_TAG_BIT_STRING (0x03U) /* BIT STRING */

Definition at line 69 of file CW_SecureChannel.cpp.

Referenced by derWalkMfCert().

◆ DER_TAG_CTX0

#define DER_TAG_CTX0 (0xA0U) /* [0] EXPLICIT — version in v3 TBSCertificate */

Definition at line 70 of file CW_SecureChannel.cpp.

Referenced by derWalkMfCert().

◆ DER_TAG_SEQUENCE

#define DER_TAG_SEQUENCE (0x30U) /* SEQUENCE (universal, constructed) */

Definition at line 68 of file CW_SecureChannel.cpp.

Referenced by derWalkMfCert().

◆ ENC_BUF_MAX_LEN

#define ENC_BUF_MAX_LEN (INPUT_BUFFER_LIMIT + AES_BLOCK_SIZE)

Definition at line 50 of file CW_SecureChannel.cpp.

◆ GETCARDCERTIFICATE_IN_BYTES

#define GETCARDCERTIFICATE_IN_BYTES (RESPONSE_GETCARDCERTIFICATE_IN_BYTES - RESPONSE_STATUS_WORDS_IN_BYTES)

Definition at line 38 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::getCardCertificate().

◆ INPUT_BUFFER_LIMIT

#define INPUT_BUFFER_LIMIT (CW_USER_DATA_PAGE_SIZE)

Definition at line 49 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcEncrypt().

◆ MAC_APDU_LEN

#define MAC_APDU_LEN (12U)

Definition at line 48 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcEncrypt().

◆ MAX_MAC_DATA_LEN

#define MAX_MAC_DATA_LEN (APDU_HEADER_LEN + MAC_APDU_LEN + ENC_BUF_MAX_LEN)

Definition at line 51 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcEncrypt().

◆ OPENSECURECHANNEL_SALT_IN_BYTES

#define OPENSECURECHANNEL_SALT_IN_BYTES (RESPONSE_OPENSECURECHANNEL_IN_BYTES - RESPONSE_STATUS_WORDS_IN_BYTES)

Definition at line 37 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::openSecureChannel().

◆ RANDOM_BYTES

#define RANDOM_BYTES 8U

Definition at line 40 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::getCardCertificate().

◆ REQUEST_MUTUALLYAUTHENTICATE_IN_BYTES

#define REQUEST_MUTUALLYAUTHENTICATE_IN_BYTES 69U

Definition at line 33 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::mutuallyAuthenticate().

◆ RESPONSE_GETCARDCERTIFICATE_IN_BYTES

#define RESPONSE_GETCARDCERTIFICATE_IN_BYTES 148U

Definition at line 27 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::getCardCertificate().

◆ RESPONSE_GETMANUFACTURERCERT_PAGE_IN_BYTES

#define RESPONSE_GETMANUFACTURERCERT_PAGE_IN_BYTES 420U

Definition at line 31 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::getManufacturerCertificate().

◆ RESPONSE_MUTUALLYAUTHENTICATE_IN_BYTES

#define RESPONSE_MUTUALLYAUTHENTICATE_IN_BYTES 66U

Definition at line 34 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::mutuallyAuthenticate().

◆ RESPONSE_OPENSECURECHANNEL_IN_BYTES

#define RESPONSE_OPENSECURECHANNEL_IN_BYTES 34U

Definition at line 32 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::openSecureChannel().

◆ RESPONSE_SELECT_IN_BYTES

#define RESPONSE_SELECT_IN_BYTES 40U

Definition at line 29 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::selectApdu().

◆ RESPONSE_STATUS_WORDS_IN_BYTES

#define RESPONSE_STATUS_WORDS_IN_BYTES 2U

Definition at line 35 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::getCardCertificate(), and CW_SecureChannel::getManufacturerCertificate().

◆ SEND_APDU_MAX_LEN

#define SEND_APDU_MAX_LEN (APDU_HEADER_LEN + APDU_LC_LEN + AES_BLOCK_SIZE + ENC_BUF_MAX_LEN)

Definition at line 52 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcEncrypt().

Function Documentation

◆ derReadLength()

bool derReadLength	(	const uint8_t *	buf,
		uint16_t	bufLen,
		uint16_t &	pos,
		uint16_t &	fieldLen )

static

Definition at line 732 of file CW_SecureChannel.cpp.

References DER_LEN_LONG_1, DER_LEN_LONG_2, and DER_LEN_LONG_FLAG.

Referenced by derSkipField(), and derWalkMfCert().

◆ derSkipField()

bool derSkipField	(	const uint8_t *	buf,
		uint16_t	bufLen,
		uint16_t &	pos )

static

Definition at line 767 of file CW_SecureChannel.cpp.

References derReadLength().

Referenced by derWalkMfCert().

◆ derWalkMfCert()

bool derWalkMfCert	(	const uint8_t *	buf,
		uint16_t	bufLen,
		uint16_t &	tbsMsgStart,
		uint16_t &	tbsMsgLen,
		const uint8_t *&	pubKey65Ptr,
		const uint8_t *&	sigPtr,
		uint8_t &	sigLen )

static

Definition at line 791 of file CW_SecureChannel.cpp.

References DER_BIT_UNUSED_ZERO, DER_EC_POINT_BYTES, DER_EC_UNCOMPRESSED, DER_TAG_BIT_STRING, DER_TAG_CTX0, DER_TAG_SEQUENCE, derReadLength(), and derSkipField().

Referenced by CW_SecureChannel::verifyCertificateChain().

Variable Documentation

◆ s_apduBuf

uint8_t s_apduBuf[SEND_APDU_MAX_LEN]

static

Definition at line 60 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcDecrypt(), and CW_SecureChannel::aesCbcEncrypt().

◆ s_dataBuf

uint8_t s_dataBuf[ENC_BUF_MAX_LEN]

static

Definition at line 62 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcDecrypt(), and CW_SecureChannel::aesCbcEncrypt().

◆ s_macBuf

uint8_t s_macBuf[MAX_MAC_DATA_LEN]

static

Definition at line 61 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::aesCbcDecrypt(), and CW_SecureChannel::aesCbcEncrypt().

◆ s_mfCertBuf

uint8_t s_mfCertBuf[CW_MANUF_CERT_MAX_BYTES]

static

Definition at line 65 of file CW_SecureChannel.cpp.

Referenced by CW_SecureChannel::preFetchManufacturerCert(), and CW_SecureChannel::verifyCertificateChain().

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ AES_BLOCK_SIZE

◆ APDU_HEADER_LEN

◆ APDU_LC_LEN

◆ CARDEPHEMERALPUBKEY_SIZE

◆ CLIENT_PRIVATE_KEY_SIZE

◆ CLIENT_PUBLIC_KEY_SIZE

◆ COMMON_PAIRING_DATA

◆ DER_BIT_UNUSED_ZERO

◆ DER_EC_POINT_BYTES

◆ DER_EC_UNCOMPRESSED

◆ DER_LEN_LONG_1

◆ DER_LEN_LONG_2

◆ DER_LEN_LONG_FLAG

◆ DER_TAG_BIT_STRING

◆ DER_TAG_CTX0

◆ DER_TAG_SEQUENCE

◆ ENC_BUF_MAX_LEN

◆ GETCARDCERTIFICATE_IN_BYTES

◆ INPUT_BUFFER_LIMIT

◆ MAC_APDU_LEN

◆ MAX_MAC_DATA_LEN

◆ OPENSECURECHANNEL_SALT_IN_BYTES

◆ RANDOM_BYTES

◆ REQUEST_MUTUALLYAUTHENTICATE_IN_BYTES

◆ RESPONSE_GETCARDCERTIFICATE_IN_BYTES

◆ RESPONSE_GETMANUFACTURERCERT_PAGE_IN_BYTES

◆ RESPONSE_MUTUALLYAUTHENTICATE_IN_BYTES

◆ RESPONSE_OPENSECURECHANNEL_IN_BYTES

◆ RESPONSE_SELECT_IN_BYTES

◆ RESPONSE_STATUS_WORDS_IN_BYTES

◆ SEND_APDU_MAX_LEN

Function Documentation

◆ derReadLength()

◆ derSkipField()

◆ derWalkMfCert()

Variable Documentation

◆ s_apduBuf

◆ s_dataBuf

◆ s_macBuf

◆ s_mfCertBuf