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DH base 2 impl - better error handling

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This commit is contained in:
Sean Parkinson
2019-08-09 12:12:59 -06:00
parent 4f714b9788
commit d4cf6e37e8
2 changed files with 30 additions and 18 deletions
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45
wolfcrypt/src/integer.c
View File

@ -2251,14 +2251,18 @@ int mp_exptmod_base_2(mp_int * X, mp_int * P, mp_int * Y)
/* now setup montgomery */
if ((err = mp_montgomery_setup(P, &mp)) != MP_OKAY) {
return err;
goto LBL_M;
}
/* setup result */
mp_init(res);
if ((err = mp_init(res)) != MP_OKAY) {
goto LBL_M;
}
/* now we need R mod m */
mp_montgomery_calc_normalization(res, P);
if ((err = mp_montgomery_calc_normalization(res, P)) != MP_OKAY) {
goto LBL_RES;
}
/* Get the top bits left over after taking WINSIZE bits starting at the
* least-significant.
@ -2270,8 +2274,14 @@ int mp_exptmod_base_2(mp_int * X, mp_int * P, mp_int * Y)
buf = X->dp[digidx--];
bitbuf = (int)(buf >> bitcnt);
/* Multiply montgomery representation of 1 by 2 ^ top */
mp_mul_2d(res, bitbuf, res);
mp_mod(res, P, res);
err = mp_mul_2d(res, bitbuf, res);
if (err != MP_OKAY) {
goto LBL_RES;
}
err = mp_mod(res, P, res);
if (err != MP_OKAY) {
goto LBL_RES;
}
/* Move out bits used */
buf <<= bitcpy;
bitcnt++;
@ -2309,28 +2319,22 @@ int mp_exptmod_base_2(mp_int * X, mp_int * P, mp_int * Y)
for (x = 0; x < WINSIZE; x++) {
err = mp_sqr(res, res);
if (err != MP_OKAY) {
#ifdef WOLFSSL_SMALL_STACK
XFREE(res, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return err;
goto LBL_RES;
}
err = (*redux)(res, P, mp);
if (err != MP_OKAY) {
#ifdef WOLFSSL_SMALL_STACK
XFREE(res, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return err;
goto LBL_RES;
}
}
/* then multiply by 2^bitbuf */
mp_mul_2d(res, bitbuf, res);
err = mp_mul_2d(res, bitbuf, res);
if (err != MP_OKAY) {
goto LBL_RES;
}
err = mp_mod(res, P, res);
if (err != MP_OKAY) {
#ifdef WOLFSSL_SMALL_STACK
XFREE(res, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return err;
goto LBL_RES;
}
/* empty window and reset */
@ -2346,10 +2350,15 @@ int mp_exptmod_base_2(mp_int * X, mp_int * P, mp_int * Y)
* of R.
*/
err = (*redux)(res, P, mp);
if (err != MP_OKAY) {
goto LBL_RES;
}
/* swap res with Y */
mp_copy(res, Y);
LBL_RES:mp_clear (res);
LBL_M:
#ifdef WOLFSSL_SMALL_STACK
XFREE(res, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif

3
wolfcrypt/src/tfm.c
View File

@ -1895,6 +1895,9 @@ static int _fp_exptmod_base_2(fp_int * X, int digits, fp_int * P,
/* now setup montgomery */
if ((err = fp_montgomery_setup(P, &mp)) != FP_OKAY) {
#ifdef WOLFSSL_SMALL_STACK
XFREE(res, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return err;
}