Merge pull request #119 from thepwrtank18/djgpp-rng

RNG bugfix for DOS (DJGPP)

.github/workflows/dos-djgpp.yml

@@ -64,8 +64,8 @@ jobs:
           git clone https://github.com/UMSKT/openssl.git openssl
           pushd openssl
           source ${{ github.workspace }}/djgpp/setenv
-          ./Configure no-threads -DOPENSSL_DEV_NO_ATOMICS --prefix=${{ github.workspace }}/djgpp DJGPP
+          ./Configure no-threads no-tests -DOPENSSL_DEV_NO_ATOMICS --prefix=${{ github.workspace }}/djgpp DJGPP
-          make && make install
+          make && make install_sw
           popd
 
       - name: Build

src/cli.cpp

@@ -423,7 +423,7 @@ int CLI::BINK1998Generate() {
     } else {
         // generate a random number to use as a serial
         BIGNUM *bnrand = BN_new();
-        BN_rand(bnrand, 19, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY);
+        UMSKT::umskt_bn_rand(bnrand, 19, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY);
 
         int oRaw;
         char *cRaw = BN_bn2dec(bnrand);
@@ -484,7 +484,7 @@ int CLI::BINK2002Generate() {
     // generate a key
     for (int i = 0; i < this->total; i++) {
         DWORD pAuthInfo;
-        RAND_bytes((BYTE *)&pAuthInfo, 4);
+        UMSKT::umskt_rand_bytes((BYTE *)&pAuthInfo, 4);
         pAuthInfo &= BITMASK(10);
 
         if (this->options.verbose) {

src/libumskt/libumskt.cpp

@@ -58,3 +58,78 @@ FNEXPORT int PIDGEN2_GenerateRetail(char* channelID, char* &keyout) {
 FNEXPORT int PIDGEN2_GenerateOEM(char* year, char* day, char* oem, char* keyout) {
     return PIDGEN2::GenerateOEM(year, day, oem, keyout);
 }
+
+// RNG utility functions
+int UMSKT::umskt_rand_bytes(unsigned char *buf, int num) {
+#if UMSKT_RNG_DJGPP
+    // DOS-compatible RNG using DJGPP's random() function
+    static bool initialized = false;
+    if (!initialized) {
+        // Get initial seed from multiple sources for better entropy
+        struct timeval tv;
+        gettimeofday(&tv, NULL);
+        
+        // Combine microseconds with BIOS timer ticks
+        unsigned long ticks = *(volatile unsigned long *)0x0040001CL;
+        int seed = (int)((tv.tv_sec ^ tv.tv_usec) ^ (ticks * 100000));
+        
+        // Initialize both random() and rand() with different seeds
+        srandom(seed);
+        srand(seed ^ 0x1234ABCD); // Use a different seed for rand
+        
+        initialized = true;
+    }
+    
+    for (int i = 0; i < num; i++) {
+        // Use random() for better randomness, especially in lower bits
+        buf[i] = (unsigned char)(random() & 0xFF);
+        
+        // Mix in rand() as an additional source
+        buf[i] ^= (unsigned char)(rand() & 0xFF);
+    }
+    return 1;
+#else
+    // Use OpenSSL's RAND_bytes for non-DOS systems
+    return RAND_bytes(buf, num);
+#endif
+}
+
+int UMSKT::umskt_bn_rand(BIGNUM *rnd, int bits, int top, int bottom) {
+#if UMSKT_RNG_DJGPP
+    // DOS-compatible RNG implementation for BIGNUMs
+    unsigned char *buf = (unsigned char *)malloc((bits + 7) / 8);
+    if (!buf) return 0;
+    
+    // Generate random bytes
+    umskt_rand_bytes(buf, (bits + 7) / 8);
+    
+    // Convert to BIGNUM
+    if (!BN_bin2bn(buf, (bits + 7) / 8, rnd)) {
+        free(buf);
+        return 0;
+    }
+    
+    free(buf);
+    
+    // Apply top/bottom constraints like BN_rand does
+    if (top != -1) {
+        if (top) {
+            if (bits == 0) {
+                BN_zero(rnd);
+                return 1;
+            }
+            BN_set_bit(rnd, bits - 1);
+        }
+        BN_mask_bits(rnd, bits);
+    }
+    
+    if (bottom) {
+        BN_set_bit(rnd, 0);
+    }
+    
+    return 1;
+#else
+    // Use OpenSSL's BN_rand for non-DOS systems
+    return BN_rand(rnd, bits, top, bottom);
+#endif
+}

src/libumskt/libumskt.h

@@ -38,6 +38,10 @@
 #include <fmt/core.h>
 #include <fmt/format.h>
 
+#ifdef __DJGPP__
+#include <sys/time.h>
+#endif
+
 // Algorithm macros
 #define PK_LENGTH               25
 #define NULL_TERMINATOR         1
@@ -59,6 +63,17 @@
 #define BYDWORD(n)                     (DWORD)(*((n) + 0) | *((n) + 1) << 8 | *((n) + 2) << 16 | *((n) + 3) << 24)
 #define BITMASK(n)                     ((1ULL << (n)) - 1)
 
+// RNG utility functions
+#ifdef __DJGPP__
+#define UMSKT_RNG_DJGPP 1
+extern "C" {
+    long int random(void);
+    int srandom(int seed);
+}
+#else
+#define UMSKT_RNG_DJGPP 0
+#endif
+
 class UMSKT {
 public:
     static std::FILE* debug;
@@ -67,7 +82,10 @@ public:
     class ConfigurationID;
 
     static void setDebugOutput(std::FILE* input);
+
+    // RNG utility functions
+    static int umskt_rand_bytes(unsigned char *buf, int num);
+    static int umskt_bn_rand(BIGNUM *rnd, int bits, int top, int bottom);
 };
 
-
 #endif //UMSKT_LIBUMSKT_H

src/libumskt/pidgen3/BINK1998.cpp

@@ -201,7 +201,7 @@ void PIDGEN3::BINK1998::Generate(
         EC_POINT *r = EC_POINT_new(eCurve);
 
         // Generate a random number c consisting of 384 bits without any constraints.
-        BN_rand(c, FIELD_BITS, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY);
+        UMSKT::umskt_bn_rand(c, FIELD_BITS, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY);
 
         // Pick a random derivative of the base point on the elliptic curve.
         // R = cG;

src/libumskt/pidgen3/BINK2002.cpp

@@ -236,7 +236,7 @@ void PIDGEN3::BINK2002::Generate(
         EC_POINT *r = EC_POINT_new(eCurve);
 
         // Generate a random number c consisting of 512 bits without any constraints.
-        BN_rand(c, FIELD_BITS_2003, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY);
+        UMSKT::umskt_bn_rand(c, FIELD_BITS_2003, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY);
 
         // R = cG
         EC_POINT_mul(eCurve, r, nullptr, basePoint, c, numContext);