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More corner cases in tfm

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Handle zero base in fp_exptmod better().
Handle negatives in fp_gcd().
Return FP_OKAY when writing out 0 with mp_toradix().
This commit is contained in:
Sean Parkinson
2019-11-22 09:56:02 +10:00
parent f56a74b6b7
commit 50c4347748
1 changed files with 14 additions and 1 deletions
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15
wolfcrypt/src/tfm.c
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@@ -2178,6 +2178,11 @@ int fp_exptmod(fp_int * G, fp_int * X, fp_int * P, fp_int * Y)
int x = fp_count_bits (X); int x = fp_count_bits (X);
#endif #endif
if (fp_iszero(G)) {
fp_set(G, 0);
return FP_OKAY;
}
/* prevent overflows */ /* prevent overflows */
if (P->used > (FP_SIZE/2)) { if (P->used > (FP_SIZE/2)) {
return FP_VAL; return FP_VAL;
@@ -2245,6 +2250,11 @@ int fp_exptmod_ex(fp_int * G, fp_int * X, int digits, fp_int * P, fp_int * Y)
int x = fp_count_bits (X); int x = fp_count_bits (X);
#endif #endif
if (fp_iszero(G)) {
fp_set(G, 0);
return FP_OKAY;
}
/* prevent overflows */ /* prevent overflows */
if (P->used > (FP_SIZE/2)) { if (P->used > (FP_SIZE/2)) {
return FP_VAL; return FP_VAL;
@@ -4437,6 +4447,9 @@ int fp_gcd(fp_int *a, fp_int *b, fp_int *c)
fp_init_copy(v, a); fp_init_copy(v, a);
} }
u->sign = FP_ZPOS;
v->sign = FP_ZPOS;
fp_init(r); fp_init(r);
while (fp_iszero(v) == FP_NO) { while (fp_iszero(v) == FP_NO) {
fp_mod(u, v, r); fp_mod(u, v, r);
@@ -4765,7 +4778,7 @@ int mp_toradix (mp_int *a, char *str, int radix)
if (fp_iszero(a) == FP_YES) { if (fp_iszero(a) == FP_YES) {
*str++ = '0'; *str++ = '0';
*str = '\0'; *str = '\0';
return FP_YES; return FP_OKAY;
} }
#ifdef WOLFSSL_SMALL_STACK #ifdef WOLFSSL_SMALL_STACK