tomcrypt/hmac_file.c
2010-06-16 12:38:16 +02:00

78 lines
1.7 KiB
C

/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org
*/
/* Submited by Dobes Vandermeer (dobes@smartt.com) */
#include "mycrypt.h"
#ifdef HMAC
/* hmac_file added by Tom St Denis */
int hmac_file(int hash, const char *fname,
const unsigned char *key, unsigned long keylen,
unsigned char *dst, unsigned long *dstlen)
{
#ifdef NO_FILE
return CRYPT_NOP;
#else
hmac_state hmac;
FILE *in;
unsigned char buf[512];
size_t x;
int err;
_ARGCHK(fname != NULL);
_ARGCHK(key != NULL);
_ARGCHK(dst != NULL);
_ARGCHK(dstlen != NULL);
if((err = hash_is_valid(hash)) != CRYPT_OK) {
return err;
}
if ((err = hmac_init(&hmac, hash, key, keylen)) != CRYPT_OK) {
return err;
}
in = fopen(fname, "rb");
if (in == NULL) {
return CRYPT_FILE_NOTFOUND;
}
/* process the file contents */
do {
x = fread(buf, 1, sizeof(buf), in);
if ((err = hmac_process(&hmac, buf, (unsigned long)x)) != CRYPT_OK) {
/* we don't trap this error since we're already returning an error! */
fclose(in);
return err;
}
} while (x == sizeof(buf));
if (fclose(in) != 0) {
return CRYPT_ERROR;
}
/* get final hmac */
if ((err = hmac_done(&hmac, dst, dstlen)) != CRYPT_OK) {
return err;
}
#ifdef CLEAN_STACK
/* clear memory */
zeromem(buf, sizeof(buf));
#endif
return CRYPT_OK;
#endif
}
#endif