From 4c4c9a8b39332516a2196490bb749933e3d1df59 Mon Sep 17 00:00:00 2001 From: Patrick Fallberg Date: Sat, 7 Mar 2015 14:47:06 +0100 Subject: [PATCH] Added SHA command to ATSHA204 backend driver The SHA command is available in ATSHA204A variants of the chip and can be used to calculate SHA256 digests of arbitrary data. This enables us to strengthen the quality of the signatures by salting signatures with node-specific data and improving the quality of random data. --- libraries/MySensors/MySigningAtsha204.cpp | 26 +++++++++++++++++++++++ libraries/MySensors/MySigningAtsha204.h | 3 ++- libraries/MySensors/utility/ATSHA204.cpp | 15 +++++++++---- libraries/MySensors/utility/ATSHA204.h | 16 +++++++++++++- 4 files changed, 54 insertions(+), 6 deletions(-) diff --git a/libraries/MySensors/MySigningAtsha204.cpp b/libraries/MySensors/MySigningAtsha204.cpp index 1effefc..146ce30 100644 --- a/libraries/MySensors/MySigningAtsha204.cpp +++ b/libraries/MySensors/MySigningAtsha204.cpp @@ -215,3 +215,29 @@ bool MySigningAtsha204::calculateSignature(MyMessage &msg) { DEBUG_ATSHA_PRINTBUF("HMAC:", &rx_buffer[SHA204_BUFFER_POS_DATA], 32); return true; // We return with the signature in rx_buffer[SHA204_BUFFER_POS_DATA] } + +// Helper to calculate a generic SHA256 digest of provided buffer (returned in rx_buffer[SHA204_BUFFER_POS_DATA]) (only supports one block) +uint8_t* MySigningAtsha204::sha256(const uint8_t* data, size_t sz) { + // Initiate SHA256 calculator + if (atsha204.sha204m_execute(SHA204_SHA, SHA_INIT, 0, 0, NULL, + SHA_COUNT_SHORT, tx_buffer, SHA_RSP_SIZE_SHORT, rx_buffer) != SHA204_SUCCESS) { + DEBUG_ATSHA_PRINTLN("Failed to initiate sha256"); + return NULL; + } + + // Calculate a hash + memset(temp_message, 0x00, SHA_MSG_SIZE); + memcpy(temp_message, data, sz); + temp_message[sz] = 0x80; + // Write length data to the last bytes + temp_message[SHA_MSG_SIZE-2] = (sz >> 5); + temp_message[SHA_MSG_SIZE-1] = (sz << 3); + DEBUG_ATSHA_PRINTBUF("Data to hash (padded):", temp_message, SHA_MSG_SIZE); + if (atsha204.sha204m_execute(SHA204_SHA, SHA_CALC, 0, SHA_MSG_SIZE, temp_message, + SHA_COUNT_LONG, tx_buffer, SHA_RSP_SIZE_LONG, rx_buffer) != SHA204_SUCCESS) { + DEBUG_ATSHA_PRINTLN("Failed to calculate sha256"); + return NULL; + } + DEBUG_ATSHA_PRINTBUF("SHA:", &rx_buffer[SHA204_BUFFER_POS_DATA], 32); + return &rx_buffer[SHA204_BUFFER_POS_DATA]; +} diff --git a/libraries/MySensors/MySigningAtsha204.h b/libraries/MySensors/MySigningAtsha204.h index 8850b2c..d6b3465 100644 --- a/libraries/MySensors/MySigningAtsha204.h +++ b/libraries/MySensors/MySigningAtsha204.h @@ -31,10 +31,11 @@ private: unsigned long timestamp; bool verification_ongoing; uint8_t current_nonce[NONCE_NUMIN_SIZE_PASSTHROUGH]; - uint8_t temp_message[32]; + uint8_t temp_message[SHA_MSG_SIZE]; uint8_t rx_buffer[SHA204_RSP_SIZE_MAX]; uint8_t tx_buffer[SHA204_CMD_SIZE_MAX]; bool calculateSignature(MyMessage &msg); + uint8_t* sha256(const uint8_t* data, size_t sz); }; #endif diff --git a/libraries/MySensors/utility/ATSHA204.cpp b/libraries/MySensors/utility/ATSHA204.cpp index da63668..21ad514 100644 --- a/libraries/MySensors/utility/ATSHA204.cpp +++ b/libraries/MySensors/utility/ATSHA204.cpp @@ -447,12 +447,19 @@ uint8_t atsha204Class::sha204m_execute(uint8_t op_code, uint8_t param1, uint16_t response_size = RANDOM_RSP_SIZE; break; - case SHA204_WRITE: - poll_delay = WRITE_DELAY; - poll_timeout = WRITE_EXEC_MAX - WRITE_DELAY; - response_size = WRITE_RSP_SIZE; + case SHA204_SHA: + poll_delay = SHA_DELAY; + poll_timeout = SHA_EXEC_MAX - SHA_DELAY; + response_size = param1 == SHA_INIT + ? SHA_RSP_SIZE_SHORT : SHA_RSP_SIZE_LONG; break; + case SHA204_WRITE: + poll_delay = WRITE_DELAY; + poll_timeout = WRITE_EXEC_MAX - WRITE_DELAY; + response_size = WRITE_RSP_SIZE; + break; + default: poll_delay = 0; poll_timeout = SHA204_COMMAND_EXEC_MAX; diff --git a/libraries/MySensors/utility/ATSHA204.h b/libraries/MySensors/utility/ATSHA204.h index cb2abc8..c2a057e 100644 --- a/libraries/MySensors/utility/ATSHA204.h +++ b/libraries/MySensors/utility/ATSHA204.h @@ -59,6 +59,7 @@ #define SHA204_HMAC ((uint8_t) 0x11) //!< HMAC command op-code #define SHA204_NONCE ((uint8_t) 0x16) //!< Nonce command op-code #define SHA204_RANDOM ((uint8_t) 0x1B) //!< Random command op-code +#define SHA204_SHA ((uint8_t) 0x47) //!< SHA command op-code #define SHA204_WRITE ((uint8_t) 0x12) //!< Write command op-code // packet size definitions @@ -122,6 +123,15 @@ #define RANDOM_SEED_UPDATE ((uint8_t) 0x00) //!< Random mode for automatic seed update #define RANDOM_NO_SEED_UPDATE ((uint8_t) 0x01) //!< Random mode for no seed update +// SHA command definitions +#define SHA_MODE_IDX SHA204_PARAM1_IDX //!< SHA command index for mode +#define SHA_PARAM2_IDX SHA204_PARAM2_IDX //!< SHA command index for 2. parameter +#define SHA_COUNT_SHORT SHA204_CMD_SIZE_MIN //!< SHA command packet size for init +#define SHA_COUNT_LONG (71) //!< SHA command packet size for calculation +#define SHA_MSG_SIZE (64) //!< SHA message data size +#define SHA_INIT ((uint8_t) 0x00) //!< SHA mode for init +#define SHA_CALC ((uint8_t) 0x01) //!< SHA mode for calculation + // Write command definitions #define WRITE_ZONE_IDX SHA204_PARAM1_IDX //!< Write command index for zone #define WRITE_ADDR_IDX SHA204_PARAM2_IDX //!< Write command index for address @@ -142,6 +152,8 @@ #define NONCE_RSP_SIZE_SHORT SHA204_RSP_SIZE_MIN //!< response size of Nonce command with mode[0:1] = 3 #define NONCE_RSP_SIZE_LONG SHA204_RSP_SIZE_MAX //!< response size of Nonce command #define RANDOM_RSP_SIZE SHA204_RSP_SIZE_MAX //!< response size of Random command +#define SHA_RSP_SIZE_SHORT SHA204_RSP_SIZE_MIN //!< response size of SHA command with mode[0:1] = 0 +#define SHA_RSP_SIZE_LONG SHA204_RSP_SIZE_MAX //!< response size of SHA command #define WRITE_RSP_SIZE SHA204_RSP_SIZE_MIN //!< response size of Write command // command timing definitions for minimum execution times (ms) @@ -149,6 +161,7 @@ #define HMAC_DELAY ((uint8_t) (27.0 * CPU_CLOCK_DEVIATION_NEGATIVE - 0.5)) #define NONCE_DELAY ((uint8_t) (22.0 * CPU_CLOCK_DEVIATION_NEGATIVE - 0.5)) #define RANDOM_DELAY ((uint8_t) (11.0 * CPU_CLOCK_DEVIATION_NEGATIVE - 0.5)) +#define SHA_DELAY ((uint8_t) (11.0 * CPU_CLOCK_DEVIATION_NEGATIVE - 0.5)) #define WRITE_DELAY ((uint8_t) ( 4.0 * CPU_CLOCK_DEVIATION_NEGATIVE - 0.5)) // command timing definitions for maximum execution times (ms) @@ -156,6 +169,7 @@ #define HMAC_EXEC_MAX ((uint8_t) (69.0 * CPU_CLOCK_DEVIATION_POSITIVE + 0.5)) #define NONCE_EXEC_MAX ((uint8_t) (60.0 * CPU_CLOCK_DEVIATION_POSITIVE + 0.5)) #define RANDOM_EXEC_MAX ((uint8_t) (50.0 * CPU_CLOCK_DEVIATION_POSITIVE + 0.5)) +#define SHA_EXEC_MAX ((uint8_t) (22.0 * CPU_CLOCK_DEVIATION_POSITIVE + 0.5)) #define WRITE_EXEC_MAX ((uint8_t) (42.0 * CPU_CLOCK_DEVIATION_POSITIVE + 0.5)) /* from sha204_config.h */ @@ -172,7 +186,7 @@ #define SHA204_COMMAND_EXEC_MAX ((uint8_t) (69.0 * CPU_CLOCK_DEVIATION_POSITIVE + 0.5)) //! maximum command delay #define SHA204_CMD_SIZE_MIN ((uint8_t) 7) //! minimum number of bytes in command (from count byte to second CRC byte) -#define SHA204_CMD_SIZE_MAX ((uint8_t) NONCE_COUNT_LONG) //! maximum size of command packet (Nonce) +#define SHA204_CMD_SIZE_MAX ((uint8_t) SHA_COUNT_LONG) //! maximum size of command packet (SHA) #define SHA204_CRC_SIZE ((uint8_t) 2) //! number of CRC bytes #define SHA204_BUFFER_POS_STATUS (1) //! buffer index of status byte in status response #define SHA204_BUFFER_POS_DATA (1) //! buffer index of first data byte in data response