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wolfSSL: Fix crypto_ec_point_compute_y_sqr() error case processing

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The result (y2) was cleared and freed in error cases, but the pointer
itself was not cleared to NULL, so the error path would have returned a
pointer to freed memory. Fix this by properly clearing the return value
in error cases. In addition, simplify the function to avoid tracking
success case separately.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2022-04-23 16:04:49 +03:00
parent 7302aa7614
commit f50d5c9a83
1 changed files with 8 additions and 20 deletions
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24
src/crypto/crypto_wolfssl.c
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@ -1650,34 +1650,22 @@ struct crypto_bignum *
crypto_ec_point_compute_y_sqr(struct crypto_ec *e, crypto_ec_point_compute_y_sqr(struct crypto_ec *e,
const struct crypto_bignum *x) const struct crypto_bignum *x)
{ {
mp_int *y2 = NULL; mp_int *y2, t;
mp_int t;
int calced = 0;
if (TEST_FAIL()) if (TEST_FAIL())
return NULL; return NULL;
if (mp_init(&t) != MP_OKAY)
return NULL;
y2 = (mp_int *) crypto_bignum_init(); y2 = (mp_int *) crypto_bignum_init();
if (!y2) if (!y2 ||
goto done; mp_init(&t) != MP_OKAY ||
mp_sqrmod((mp_int *) x, &e->prime, y2) != 0 ||
if (mp_sqrmod((mp_int *) x, &e->prime, y2) != 0 ||
mp_mulmod((mp_int *) x, y2, &e->prime, y2) != 0 || mp_mulmod((mp_int *) x, y2, &e->prime, y2) != 0 ||
mp_mulmod((mp_int *) x, &e->a, &e->prime, &t) != 0 || mp_mulmod((mp_int *) x, &e->a, &e->prime, &t) != 0 ||
mp_addmod(y2, &t, &e->prime, y2) != 0 || mp_addmod(y2, &t, &e->prime, y2) != 0 ||
mp_addmod(y2, &e->b, &e->prime, y2) != 0) mp_addmod(y2, &e->b, &e->prime, y2) != 0) {
goto done;
calced = 1;
done:
if (!calced) {
if (y2) {
mp_clear(y2); mp_clear(y2);
os_free(y2); os_free(y2);
} y2 = NULL;
} }
mp_clear(&t); mp_clear(&t);