Skip to content

Commit

Permalink
new: 'include_header' argument to HMAC and CRC32
Browse files Browse the repository at this point in the history
  • Loading branch information
@johandc
johandc committed Nov 24, 2015
1 parent a7f5dd2 commit 9a6e87d
Show file tree
Hide file tree
Showing 7 changed files with 49 additions and 25 deletions.
8 changes: 6 additions & 2 deletions include/csp/csp_crc32.h
View file
Expand Up @@ -21,6 +21,8 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#ifndef _CSP_CRC32_H_
#define _CSP_CRC32_H_

#include <csp/csp.h>

#ifdef __cplusplus
extern "C" {
#endif
Expand All @@ -33,16 +35,18 @@ void csp_crc32_gentab(void);
/**
* Append CRC32 checksum to packet
* @param packet Packet to append checksum
* @param include_header use header in calculation (this will not modify the flags field)
* @return 0 on success, -1 on error
*/
int csp_crc32_append(csp_packet_t * packet);
int csp_crc32_append(csp_packet_t * packet, bool include_header);

/**
* Verify CRC32 checksum on packet
* @param packet Packet to verify
* @param include_header use header in calculation (this will not modify the flags field)
* @return 0 if checksum is valid, -1 otherwise
*/
int csp_crc32_verify(csp_packet_t * packet);
int csp_crc32_verify(csp_packet_t * packet, bool include_header);

/**
* Calculate checksum for a given memory area
Expand Down
17 changes: 13 additions & 4 deletions src/crypto/csp_hmac.c
View file
Expand Up @@ -22,6 +22,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

#include <stdint.h>
#include <string.h>
#include <stdbool.h>

/* CSP includes */
#include <csp/csp.h>
Expand Down Expand Up @@ -148,7 +149,7 @@ int csp_hmac_set_key(char * key, uint32_t keylen) {

}

int csp_hmac_append(csp_packet_t * packet) {
int csp_hmac_append(csp_packet_t * packet, bool include_header) {

/* NULL pointer check */
if (packet == NULL)
Expand All @@ -157,7 +158,11 @@ int csp_hmac_append(csp_packet_t * packet) {
uint8_t hmac[SHA1_DIGESTSIZE];

/* Calculate HMAC */
csp_hmac_memory(csp_hmac_key, HMAC_KEY_LENGTH, packet->data, packet->length, hmac);
if (include_header) {
csp_hmac_memory(csp_hmac_key, HMAC_KEY_LENGTH, (uint8_t *) &packet->id, packet->length + sizeof(packet->id), hmac);
} else {
csp_hmac_memory(csp_hmac_key, HMAC_KEY_LENGTH, packet->data, packet->length, hmac);
}

/* Truncate hash and copy to packet */
memcpy(&packet->data[packet->length], hmac, CSP_HMAC_LENGTH);
Expand All @@ -167,7 +172,7 @@ int csp_hmac_append(csp_packet_t * packet) {

}

int csp_hmac_verify(csp_packet_t * packet) {
int csp_hmac_verify(csp_packet_t * packet, bool include_header) {

/* NULL pointer check */
if (packet == NULL)
Expand All @@ -176,7 +181,11 @@ int csp_hmac_verify(csp_packet_t * packet) {
uint8_t hmac[SHA1_DIGESTSIZE];

/* Calculate HMAC */
csp_hmac_memory(csp_hmac_key, HMAC_KEY_LENGTH, packet->data, packet->length - CSP_HMAC_LENGTH, hmac);
if (include_header) {
csp_hmac_memory(csp_hmac_key, HMAC_KEY_LENGTH, (uint8_t *) &packet->id, packet->length + sizeof(packet->id) - CSP_HMAC_LENGTH, hmac);
} else {
csp_hmac_memory(csp_hmac_key, HMAC_KEY_LENGTH, packet->data, packet->length - CSP_HMAC_LENGTH, hmac);
}

/* Compare calculated HMAC with packet header */
if (memcmp(&packet->data[packet->length] - CSP_HMAC_LENGTH, hmac, CSP_HMAC_LENGTH) != 0) {
Expand Down
7 changes: 5 additions & 2 deletions src/crypto/csp_hmac.h
View file
Expand Up @@ -26,22 +26,25 @@ extern "C" {
#endif

#include <stdint.h>
#include <stdbool.h>

#define CSP_HMAC_LENGTH 4

/**
* Append HMAC to packet
* @param packet Pointer to packet
* @param include_header use header in hmac calculation (this will not modify the flags field)
* @return 0 on success, -1 on failure
*/
int csp_hmac_append(csp_packet_t * packet);
int csp_hmac_append(csp_packet_t * packet, bool include_header);

/**
* Verify HMAC of packet
* @param packet Pointer to packet
* @param include_header use header in hmac calculation (this will not modify the flags field)
* @return 0 on correct HMAC, -1 if verification failed
*/
int csp_hmac_verify(csp_packet_t * packet);
int csp_hmac_verify(csp_packet_t * packet, bool include_header);

#ifdef __cplusplus
} /* extern "C" */
Expand Down
16 changes: 12 additions & 4 deletions src/csp_crc32.c
View file
Expand Up @@ -80,7 +80,7 @@ uint32_t csp_crc32_memory(const uint8_t * data, uint32_t length) {
return (crc ^ 0xFFFFFFFF);
}

int csp_crc32_append(csp_packet_t * packet) {
int csp_crc32_append(csp_packet_t * packet, bool include_header) {

uint32_t crc;

Expand All @@ -89,7 +89,11 @@ int csp_crc32_append(csp_packet_t * packet) {
return CSP_ERR_INVAL;

/* Calculate CRC32, convert to network byte order */
crc = csp_crc32_memory(packet->data, packet->length);
if (include_header) {
crc = csp_crc32_memory((uint8_t *) &packet->id, packet->length + sizeof(packet->id));
} else {
crc = csp_crc32_memory(packet->data, packet->length);
}
crc = csp_hton32(crc);

/* Copy checksum to packet */
Expand All @@ -100,7 +104,7 @@ int csp_crc32_append(csp_packet_t * packet) {

}

int csp_crc32_verify(csp_packet_t * packet) {
int csp_crc32_verify(csp_packet_t * packet, bool include_header) {

uint32_t crc;

Expand All @@ -112,7 +116,11 @@ int csp_crc32_verify(csp_packet_t * packet) {
return CSP_ERR_INVAL;

/* Calculate CRC32, convert to network byte order */
crc = csp_crc32_memory(packet->data, packet->length - sizeof(uint32_t));
if (include_header) {
crc = csp_crc32_memory((uint8_t *) &packet->id, packet->length + sizeof(packet->id) - sizeof(uint32_t));
} else {
crc = csp_crc32_memory(packet->data, packet->length - sizeof(uint32_t));
}
crc = csp_hton32(crc);

/* Compare calculated checksum with packet header */
Expand Down
14 changes: 7 additions & 7 deletions src/csp_io.c
View file
Expand Up @@ -225,6 +225,9 @@ int csp_send_direct(csp_id_t idout, csp_packet_t * packet, csp_iface_t * ifout,
csp_log_packet("OUT: S %u, D %u, Dp %u, Sp %u, Pr %u, Fl 0x%02X, Sz %u VIA: %s",
idout.src, idout.dst, idout.dport, idout.sport, idout.pri, idout.flags, packet->length, ifout->name);

/* Copy identifier to packet (before crc, xtea and hmac) */
packet->id.ext = idout.ext;

#ifdef CSP_USE_PROMISC
/* Loopback traffic is added to promisc queue by the router */
if (idout.dst != my_address && idout.src == my_address) {
Expand All @@ -238,8 +241,8 @@ int csp_send_direct(csp_id_t idout, csp_packet_t * packet, csp_iface_t * ifout,
/* Append HMAC */
if (idout.flags & CSP_FHMAC) {
#ifdef CSP_USE_HMAC
/* Calculate and add HMAC */
if (csp_hmac_append(packet) != 0) {
/* Calculate and add HMAC (does not include header for backwards compatability with csp1.x) */
if (csp_hmac_append(packet, false) != 0) {
/* HMAC append failed */
csp_log_warn("HMAC append failed!");
goto tx_err;
Expand All @@ -253,8 +256,8 @@ int csp_send_direct(csp_id_t idout, csp_packet_t * packet, csp_iface_t * ifout,
/* Append CRC32 */
if (idout.flags & CSP_FCRC32) {
#ifdef CSP_USE_CRC32
/* Calculate and add CRC32 */
if (csp_crc32_append(packet) != 0) {
/* Calculate and add CRC32 (does not include header for backwards compatability with csp1.x) */
if (csp_crc32_append(packet, false) != 0) {
/* CRC32 append failed */
csp_log_warn("CRC32 append failed!");
goto tx_err;
Expand Down Expand Up @@ -291,9 +294,6 @@ int csp_send_direct(csp_id_t idout, csp_packet_t * packet, csp_iface_t * ifout,
}
}

/* Copy identifier to packet */
packet->id.ext = idout.ext;

/* Store length before passing to interface */
uint16_t bytes = packet->length;
uint16_t mtu = ifout->mtu;
Expand Down
8 changes: 4 additions & 4 deletions src/csp_route.c
View file
Expand Up @@ -85,8 +85,8 @@ static int csp_route_security_check(uint32_t security_opts, csp_iface_t * interf
#ifdef CSP_USE_CRC32
if (packet->length < 4)
csp_log_error("Too short packet for CRC32, %u", packet->length);
/* Verify CRC32 */
if (csp_crc32_verify(packet) != 0) {
/* Verify CRC32 (does not include header for backwards compatability with csp1.x) */
if (csp_crc32_verify(packet, false) != 0) {
/* Checksum failed */
csp_log_error("CRC32 verification error! Discarding packet");
interface->rx_error++;
Expand All @@ -104,8 +104,8 @@ static int csp_route_security_check(uint32_t security_opts, csp_iface_t * interf
/* HMAC authenticated packet */
if (packet->id.flags & CSP_FHMAC) {
#ifdef CSP_USE_HMAC
/* Verify HMAC */
if (csp_hmac_verify(packet) != 0) {
/* Verify HMAC (does not include header for backwards compatability with csp1.x) */
if (csp_hmac_verify(packet, false) != 0) {
/* HMAC failed */
csp_log_error("HMAC verification error! Discarding packet");
interface->autherr++;
Expand Down
4 changes: 2 additions & 2 deletions src/interfaces/csp_if_kiss.c
View file
Expand Up @@ -52,7 +52,7 @@ static int csp_kiss_tx(csp_iface_t * interface, csp_packet_t * packet, uint32_t
return CSP_ERR_DRIVER;

/* Add CRC32 checksum */
csp_crc32_append(packet);
csp_crc32_append(packet, false);

/* Save the outgoing id in the buffer */
packet->id.ext = csp_hton32(packet->id.ext);
Expand Down Expand Up @@ -172,7 +172,7 @@ void csp_kiss_rx(csp_iface_t * interface, uint8_t * buf, int len, void * pxTaskW
driver->rx_packet->id.ext = csp_ntoh32(driver->rx_packet->id.ext);

/* Validate CRC */
if (csp_crc32_verify(driver->rx_packet) != CSP_ERR_NONE) {
if (csp_crc32_verify(driver->rx_packet, false) != CSP_ERR_NONE) {
csp_log_warn("KISS invalid crc frame skipped, len: %u", driver->rx_packet->length);
interface->rx_error++;
driver->rx_mode = KISS_MODE_NOT_STARTED;
Expand Down

0 comments on commit 9a6e87d

Please sign in to comment.