LibCrypto+LibTLS: Use AK/Random.h

This makes it possible to build both of these on Linux.

Libraries/LibCrypto/NumberTheory/ModularFunctions.h

@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include <AK/Random.h>
 #include <LibCrypto/BigInt/UnsignedBigInteger.h>
 
 //#define NT_DEBUG
@@ -289,7 +290,7 @@ static UnsignedBigInteger random_number(const UnsignedBigInteger& min, const Uns
     // FIXME: Need a cryptographically secure rng
     auto size = range.trimmed_length() * sizeof(u32);
     u8 buf[size];
-    arc4random_buf(buf, size);
+    AK::fill_with_random(buf, size);
     Vector<u32> vec;
     for (size_t i = 0; i < size / sizeof(u32); ++i) {
         vec.append(*(u32*)buf + i);

Libraries/LibCrypto/PK/Code/EMSA_PSS.h

@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include <AK/Random.h>
 #include <LibCrypto/PK/Code/Code.h>
 
 static constexpr u8 zeros[] { 0, 0, 0, 0, 0, 0, 0, 0 };
@@ -56,7 +57,7 @@ public:
         auto em_length = (em_bits + 7) / 8;
         u8 salt[SaltLength];
 
-        arc4random_buf(salt, SaltLength);
+        AK::fill_with_random(salt, SaltLength);
 
         if (em_length < hash_length + SaltLength + 2) {
             dbg() << "Ooops...encoding error";

Libraries/LibCrypto/PK/RSA.cpp

@@ -24,6 +24,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <AK/Random.h>
 #include <LibCrypto/ASN1/ASN1.h>
 #include <LibCrypto/ASN1/DER.h>
 #include <LibCrypto/ASN1/PEM.h>
@@ -236,7 +237,10 @@ void RSA_PKCS1_EME::encrypt(const ByteBuffer& in, ByteBuffer& out)
     auto ps_length = mod_len - in.size() - 3;
     u8 ps[ps_length];
 
-    arc4random_buf(ps, ps_length);
+    // FIXME: Without this assertion, GCC refuses to compile due to a memcpy overflow(!?)
+    ASSERT(ps_length < 16384);
+
+    AK::fill_with_random(ps, ps_length);
     // since arc4random can create zeros (shocking!)
     // we have to go through and un-zero the zeros
     for (size_t i = 0; i < ps_length; ++i)

Libraries/LibTLS/ClientHandshake.cpp

@@ -24,6 +24,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <AK/Random.h>
 #include <LibCore/Timer.h>
 #include <LibCrypto/ASN1/DER.h>
 #include <LibCrypto/PK/Code/EMSA_PSS.h>
@@ -245,12 +246,13 @@ void TLSv12::build_random(PacketBuilder& builder)
     u8 random_bytes[48];
     size_t bytes = 48;
 
-    arc4random_buf(random_bytes, bytes);
+    AK::fill_with_random(random_bytes, bytes);
 
     // remove zeros from the random bytes
-    for (size_t i = 0; i < bytes; ++i)
+    for (size_t i = 0; i < bytes; ++i) {
         if (!random_bytes[i])
-            random_bytes[i--] = arc4random();
+            random_bytes[i--] = AK::get_random<u8>();
+    }
 
     if (m_context.is_server) {
         dbg() << "Server mode not supported";

Libraries/LibTLS/Handshake.cpp

@@ -24,6 +24,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <AK/Random.h>
 #include <LibCore/Timer.h>
 #include <LibCrypto/ASN1/DER.h>
 #include <LibCrypto/PK/Code/EMSA_PSS.h>
@@ -33,7 +34,7 @@ namespace TLS {
 
 ByteBuffer TLSv12::build_hello()
 {
-    arc4random_buf(&m_context.local_random, 32);
+    AK::fill_with_random(&m_context.local_random, 32);
 
     auto packet_version = (u16)m_context.version;
     auto version = (u16)m_context.version;
@@ -42,7 +43,7 @@ ByteBuffer TLSv12::build_hello()
     builder.append((u8)ClientHello);
 
     // hello length (for later)
-    u8 dummy[3];
+    u8 dummy[3] = {};
     builder.append(dummy, 3);
 
     auto start_length = builder.length();