unleashed-firmware/applications/plugins/totp/services/hmac/hmac_common.h
2022-10-13 17:00:20 +03:00

64 lines
1.9 KiB
C

#include <string.h>
#include "sha256.h"
#include "memxor.h"
#define IPAD 0x36
#define OPAD 0x5c
/* Concatenate two preprocessor tokens. */
#define _GLHMAC_CONCAT_(prefix, suffix) prefix##suffix
#define _GLHMAC_CONCAT(prefix, suffix) _GLHMAC_CONCAT_(prefix, suffix)
#if GL_HMAC_NAME == 5
#define HMAC_ALG md5
#else
#define HMAC_ALG _GLHMAC_CONCAT(sha, GL_HMAC_NAME)
#endif
#define GL_HMAC_CTX _GLHMAC_CONCAT(HMAC_ALG, _ctx)
#define GL_HMAC_FN _GLHMAC_CONCAT(hmac_, HMAC_ALG)
#define GL_HMAC_FN_INIT _GLHMAC_CONCAT(HMAC_ALG, _init_ctx)
#define GL_HMAC_FN_BLOC _GLHMAC_CONCAT(HMAC_ALG, _process_block)
#define GL_HMAC_FN_PROC _GLHMAC_CONCAT(HMAC_ALG, _process_bytes)
#define GL_HMAC_FN_FINI _GLHMAC_CONCAT(HMAC_ALG, _finish_ctx)
static void
hmac_hash(const void* key, size_t keylen, const void* in, size_t inlen, int pad, void* resbuf) {
struct GL_HMAC_CTX hmac_ctx;
char block[GL_HMAC_BLOCKSIZE];
memset(block, pad, sizeof block);
memxor(block, key, keylen);
GL_HMAC_FN_INIT(&hmac_ctx);
GL_HMAC_FN_BLOC(block, sizeof block, &hmac_ctx);
GL_HMAC_FN_PROC(in, inlen, &hmac_ctx);
GL_HMAC_FN_FINI(&hmac_ctx, resbuf);
}
int GL_HMAC_FN(const void* key, size_t keylen, const void* in, size_t inlen, void* resbuf) {
char optkeybuf[GL_HMAC_HASHSIZE];
char innerhash[GL_HMAC_HASHSIZE];
/* Ensure key size is <= block size. */
if(keylen > GL_HMAC_BLOCKSIZE) {
struct GL_HMAC_CTX keyhash;
GL_HMAC_FN_INIT(&keyhash);
GL_HMAC_FN_PROC(key, keylen, &keyhash);
GL_HMAC_FN_FINI(&keyhash, optkeybuf);
key = optkeybuf;
/* zero padding of the key to the block size
is implicit in the memxor. */
keylen = sizeof optkeybuf;
}
/* Compute INNERHASH from KEY and IN. */
hmac_hash(key, keylen, in, inlen, IPAD, innerhash);
/* Compute result from KEY and INNERHASH. */
hmac_hash(key, keylen, innerhash, sizeof innerhash, OPAD, resbuf);
return 0;
}