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Code Issues Releases Wiki Activity

Better error propagation in _fp_exptmod_ct

pull/3766/head
Guido Vranken 2021-02-16 19:54:59 +01:00
parent 830de9a9fb
commit b47809e718
1 changed files with 14 additions and 2 deletions
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16
wolfcrypt/src/tfm.c
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@ -1944,11 +1944,23 @@ static int _fp_exptmod_ct(fp_int * G, fp_int * X, int digits, fp_int * P,
/* now set R[0][1] to G * R mod m */ /* now set R[0][1] to G * R mod m */
if (fp_cmp_mag(P, G) != FP_GT) { if (fp_cmp_mag(P, G) != FP_GT) {
/* G > P so we reduce it first */ /* G > P so we reduce it first */
fp_mod(G, P, &R[1]); err = fp_mod(G, P, &R[1]);
if (err != FP_OKAY) {
#ifdef WOLFSSL_SMALL_STACK
XFREE(R, NULL, DYNAMIC_TYPE_BIGINT);
#endif
return err;
}
} else { } else {
fp_copy(G, &R[1]); fp_copy(G, &R[1]);
} }
fp_mulmod (&R[1], &R[0], P, &R[1]); err = fp_mulmod (&R[1], &R[0], P, &R[1]);
if (err != FP_OKAY) {
#ifdef WOLFSSL_SMALL_STACK
XFREE(R, NULL, DYNAMIC_TYPE_BIGINT);
#endif
return err;
}
/* for j = t-1 downto 0 do /* for j = t-1 downto 0 do
r_!k = R0*R1; r_k = r_k^2 r_!k = R0*R1; r_k = r_k^2