Avoid potential overflow to the sign bit when shifting left 24 places
Although there are platforms where int is 64 bit, 2GiB large BIGNUMs
instead of 4GiB should be "big enough for everybody".
@@ -45,7 +45,7 @@ BIGNUM *BN_mpi2bn(const unsigned char *d, int n, BIGNUM *ain)
int neg = 0;
BIGNUM *a = NULL;
- if (n < 4) {
+ if (n < 4 || (d[0] & 0x80) != 0) {
BNerr(BN_F_BN_MPI2BN, BN_R_INVALID_LENGTH);
return NULL;
}
