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TFM prime checking: check for more errors

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Small stack can produce errors that were being ignored.
Checks for valid size in fp_exptmod was being ignored.
This commit is contained in:
Sean Parkinson
2021-05-14 09:19:22 +10:00
parent 0a8996f467
commit ed3a0ae694
1 changed files with 24 additions and 12 deletions
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36
wolfcrypt/src/tfm.c
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@@ -4775,25 +4775,28 @@ static int fp_prime_miller_rabin_ex(fp_int * a, fp_int * b, int *result,
defined(WOLFSSL_HAVE_SP_DH) defined(WOLFSSL_HAVE_SP_DH)
#ifndef WOLFSSL_SP_NO_2048 #ifndef WOLFSSL_SP_NO_2048
if (fp_count_bits(a) == 1024 && fp_isodd(a)) if (fp_count_bits(a) == 1024 && fp_isodd(a))
sp_ModExp_1024(b, r, a, y); err = sp_ModExp_1024(b, r, a, y);
else if (fp_count_bits(a) == 2048 && fp_isodd(a)) else if (fp_count_bits(a) == 2048 && fp_isodd(a))
sp_ModExp_2048(b, r, a, y); err = sp_ModExp_2048(b, r, a, y);
else else
#endif #endif
#ifndef WOLFSSL_SP_NO_3072 #ifndef WOLFSSL_SP_NO_3072
if (fp_count_bits(a) == 1536 && fp_isodd(a)) if (fp_count_bits(a) == 1536 && fp_isodd(a))
sp_ModExp_1536(b, r, a, y); err = sp_ModExp_1536(b, r, a, y);
else if (fp_count_bits(a) == 3072 && fp_isodd(a)) else if (fp_count_bits(a) == 3072 && fp_isodd(a))
sp_ModExp_3072(b, r, a, y); err = sp_ModExp_3072(b, r, a, y);
else else
#endif #endif
#ifdef WOLFSSL_SP_4096 #ifdef WOLFSSL_SP_4096
if (fp_count_bits(a) == 4096 && fp_isodd(a)) if (fp_count_bits(a) == 4096 && fp_isodd(a))
sp_ModExp_4096(b, r, a, y); err = sp_ModExp_4096(b, r, a, y);
else else
#endif #endif
#endif #endif
fp_exptmod(b, r, a, y); err = fp_exptmod(b, r, a, y);
if (err != FP_OKAY) {
return err;
}
/* if y != 1 and y != n1 do */ /* if y != 1 and y != n1 do */
if (fp_cmp_d (y, 1) != FP_EQ && fp_cmp (y, n1) != FP_EQ) { if (fp_cmp_d (y, 1) != FP_EQ && fp_cmp (y, n1) != FP_EQ) {
@@ -4906,6 +4909,7 @@ int fp_isprime_ex(fp_int *a, int t, int* result)
#endif #endif
fp_digit d; fp_digit d;
int r, res; int r, res;
int err;
if (t <= 0 || t > FP_PRIME_SIZE) { if (t <= 0 || t > FP_PRIME_SIZE) {
*result = FP_NO; *result = FP_NO;
@@ -4930,7 +4934,7 @@ int fp_isprime_ex(fp_int *a, int t, int* result)
res = fp_mod_d(a, primes[r], &d); res = fp_mod_d(a, primes[r], &d);
if (res != MP_OKAY || d == 0) { if (res != MP_OKAY || d == 0) {
*result = FP_NO; *result = FP_NO;
return FP_OKAY; return res;
} }
} }
@@ -4943,13 +4947,13 @@ int fp_isprime_ex(fp_int *a, int t, int* result)
fp_init(b); fp_init(b);
for (r = 0; r < t; r++) { for (r = 0; r < t; r++) {
fp_set(b, primes[r]); fp_set(b, primes[r]);
fp_prime_miller_rabin(a, b, &res); err = fp_prime_miller_rabin(a, b, &res);
if (res == FP_NO) { if ((err != FP_OKAY) || (res == FP_NO)) {
*result = FP_NO; *result = res;
#ifdef WOLFSSL_SMALL_STACK #ifdef WOLFSSL_SMALL_STACK
XFREE(b, NULL, DYNAMIC_TYPE_BIGINT); XFREE(b, NULL, DYNAMIC_TYPE_BIGINT);
#endif #endif
return FP_OKAY; return err;
} }
} }
*result = FP_YES; *result = FP_YES;
@@ -5023,6 +5027,7 @@ int mp_prime_is_prime_ex(mp_int* a, int t, int* result, WC_RNG* rng)
b = (fp_int*)XMALLOC(sizeof(fp_int) * 5, NULL, DYNAMIC_TYPE_BIGINT); b = (fp_int*)XMALLOC(sizeof(fp_int) * 5, NULL, DYNAMIC_TYPE_BIGINT);
if (b == NULL) { if (b == NULL) {
XFREE(base, NULL, DYNAMIC_TYPE_TMP_BUFFER);
return FP_MEM; return FP_MEM;
} }
c = &b[1]; n1 = &b[2]; y= &b[3]; r = &b[4]; c = &b[1]; n1 = &b[2]; y= &b[3]; r = &b[4];
@@ -5063,7 +5068,14 @@ int mp_prime_is_prime_ex(mp_int* a, int t, int* result, WC_RNG* rng)
continue; continue;
} }
fp_prime_miller_rabin_ex(a, b, &ret, n1, y, r); err = fp_prime_miller_rabin_ex(a, b, &ret, n1, y, r);
if (err != FP_OKAY) {
#ifdef WOLFSSL_SMALL_STACK
XFREE(b, NULL, DYNAMIC_TYPE_BIGINT);
XFREE(base, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return err;
}
if (ret == FP_NO) if (ret == FP_NO)
break; break;
fp_zero(b); fp_zero(b);