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-rw-r--r--crypto/rsa/rsa_gen.c32
1 files changed, 26 insertions, 6 deletions
diff --git a/crypto/rsa/rsa_gen.c b/crypto/rsa/rsa_gen.c
index a85493d6097b..9ca5dfefb707 100644
--- a/crypto/rsa/rsa_gen.c
+++ b/crypto/rsa/rsa_gen.c
@@ -109,6 +109,7 @@ static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
BIGNUM *pr0, *d, *p;
int bitsp, bitsq, ok = -1, n = 0;
BN_CTX *ctx = NULL;
+ unsigned long error = 0;
/*
* When generating ridiculously small keys, we can get stuck
@@ -155,16 +156,26 @@ static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
if (BN_copy(rsa->e, e_value) == NULL)
goto err;
+ BN_set_flags(r2, BN_FLG_CONSTTIME);
/* generate p and q */
for (;;) {
if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
goto err;
if (!BN_sub(r2, rsa->p, BN_value_one()))
goto err;
- if (!BN_gcd(r1, r2, rsa->e, ctx))
- goto err;
- if (BN_is_one(r1))
+ ERR_set_mark();
+ if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) {
+ /* GCD == 1 since inverse exists */
break;
+ }
+ error = ERR_peek_last_error();
+ if (ERR_GET_LIB(error) == ERR_LIB_BN
+ && ERR_GET_REASON(error) == BN_R_NO_INVERSE) {
+ /* GCD != 1 */
+ ERR_pop_to_mark();
+ } else {
+ goto err;
+ }
if (!BN_GENCB_call(cb, 2, n++))
goto err;
}
@@ -177,10 +188,19 @@ static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
} while (BN_cmp(rsa->p, rsa->q) == 0);
if (!BN_sub(r2, rsa->q, BN_value_one()))
goto err;
- if (!BN_gcd(r1, r2, rsa->e, ctx))
- goto err;
- if (BN_is_one(r1))
+ ERR_set_mark();
+ if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) {
+ /* GCD == 1 since inverse exists */
break;
+ }
+ error = ERR_peek_last_error();
+ if (ERR_GET_LIB(error) == ERR_LIB_BN
+ && ERR_GET_REASON(error) == BN_R_NO_INVERSE) {
+ /* GCD != 1 */
+ ERR_pop_to_mark();
+ } else {
+ goto err;
+ }
if (!BN_GENCB_call(cb, 2, n++))
goto err;
}