jeirmeister/Cockatrice
1
0
Fork 0
mirror of https://github.com/Cockatrice/Cockatrice.git synced 2026-09-25 11:56:11 -07:00
Code Issues Projects Releases Packages Wiki Activity Actions 3

[Security] Use a CSPRNG for salts, tokens, and RNG seeding

Browse source 
Password salts and activation tokens were generated with the global SFMT
RNG, which was seeded from a 32-bit timestamp, making registration
salts and activation tokens predictable. The game RNG used the same
timestamp seed across restarts.

Add CryptoUtil backed by OpenSSL RAND_bytes and use it for salt/token
generation and to seed RNG_SFMT with a 64-bit CSPRNG value in both the
client and server. Link libcockatrice_utility against OpenSSL::Crypto.

Took 30 seconds

Took 25 minutes
This commit is contained in:
Lukas Brübach 2026-08-04 10:02:35 +02:00 • committed by GitHub
parent 704611fc1f
commit a01dca4f6c
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
9 changed files with 101 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

26
libcockatrice_utility/libcockatrice/utility/passwordhasher.cpp
View file

@ -1,7 +1,7 @@
#include "passwordhasher.h"
#include <QCryptographicHash>
#include <libcockatrice/rng/rng_sfmt.h>
#include <libcockatrice/utility/cryptoutil.h>
QString PasswordHasher::computeHash(const QString &password, const QString &salt)
{
@ -21,12 +21,28 @@ QString PasswordHasher::generateRandomSalt(const int len)
static const char alphanum[] = "0123456789"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz";
const int size = sizeof(alphanum) - 1;
// Two bytes per character, corrected for modulo bias via rejection sampling.
const int bucketSize = 65536 / size;
const int limit = bucketSize * size;
QString ret;
int size = sizeof(alphanum) - 1;
ret.reserve(len);
QByteArray random = CryptoUtil::randomBytes(len * 2);
int bytesUsed = 0;
for (int i = 0; i < len; ++i) {
ret.append(alphanum[rng->rand(0, size)]);
unsigned int value;
do {
if (bytesUsed >= random.size()) {
random = CryptoUtil::randomBytes(len * 2);
bytesUsed = 0;
}
value = static_cast<unsigned int>(static_cast<unsigned char>(random.at(bytesUsed))) << 8 |
static_cast<unsigned int>(static_cast<unsigned char>(random.at(bytesUsed + 1)));
bytesUsed += 2;
} while (value >= limit);
ret.append(alphanum[value / bucketSize]);
}
return ret;
@ -34,5 +50,5 @@ QString PasswordHasher::generateRandomSalt(const int len)
QString PasswordHasher::generateActivationToken()
{
return QCryptographicHash::hash(generateRandomSalt().toUtf8(), QCryptographicHash::Md5).toBase64().left(16);
return QString(CryptoUtil::randomBytes(16).toBase64().left(16));
}