AK+Everywhere: Change AK::fill_with_random to accept a Bytes object

Rather than the very C-like API we currently have, accepting a void* and
a length, let's take a Bytes object instead. In almost all existing
cases, the compiler figures out the length.

AK/Random.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <AK/Platform.h>
+#include <AK/Span.h>
 #include <AK/StdLibExtras.h>
 #include <AK/Types.h>
 #include <stdlib.h>
@@ -21,36 +22,32 @@
 
 namespace AK {
 
-inline void fill_with_random([[maybe_unused]] void* buffer, [[maybe_unused]] size_t length)
+inline void fill_with_random([[maybe_unused]] Bytes bytes)
 {
 #if defined(AK_OS_SERENITY) || defined(AK_OS_ANDROID)
-    arc4random_buf(buffer, length);
+    arc4random_buf(bytes.data(), bytes.size());
 #elif defined(OSS_FUZZ)
 #else
     auto fill_with_random_fallback = [&]() {
-        char* char_buffer = static_cast<char*>(buffer);
+        for (auto& byte : bytes)
-        for (size_t i = 0; i < length; i++)
+            byte = rand();
-            char_buffer[i] = rand();
     };
 
 #    if defined(__unix__) or defined(AK_OS_MACOS)
     // The maximum permitted value for the getentropy length argument.
     static constexpr size_t getentropy_length_limit = 256;
-
+    auto iterations = bytes.size() / getentropy_length_limit;
-    auto iterations = length / getentropy_length_limit;
-    auto remainder = length % getentropy_length_limit;
-    auto address = reinterpret_cast<FlatPtr>(buffer);
 
     for (size_t i = 0; i < iterations; ++i) {
-        if (getentropy(reinterpret_cast<void*>(address), getentropy_length_limit) != 0) {
+        if (getentropy(bytes.data(), getentropy_length_limit) != 0) {
             fill_with_random_fallback();
             return;
         }
 
-        address += getentropy_length_limit;
+        bytes = bytes.slice(getentropy_length_limit);
     }
 
-    if (remainder == 0 || getentropy(reinterpret_cast<void*>(address), remainder) == 0)
+    if (bytes.is_empty() || getentropy(bytes.data(), bytes.size()) == 0)
         return;
 #    endif
 
@@ -62,7 +59,7 @@ template<typename T>
 inline T get_random()
 {
     T t;
-    fill_with_random(&t, sizeof(T));
+    fill_with_random({ &t, sizeof(T) });
     return t;
 }
 

Tests/LibC/TestSnprintf.cpp

@@ -59,7 +59,7 @@ static bool test_single(Testcase<TArg> const& testcase)
 
     // Setup
     ByteBuffer actual = ByteBuffer::create_uninitialized(SANDBOX_CANARY_SIZE + testcase.dest_n + SANDBOX_CANARY_SIZE).release_value();
-    fill_with_random(actual.data(), actual.size());
+    fill_with_random(actual);
     ByteBuffer expected = actual;
     VERIFY(actual.offset_pointer(0) != expected.offset_pointer(0));
     actual.overwrite(SANDBOX_CANARY_SIZE, testcase.dest, testcase.dest_n);

Tests/LibC/TestStrlcpy.cpp

@@ -56,7 +56,7 @@ static bool test_single(Testcase const& testcase)
 
     // Setup
     ByteBuffer actual = ByteBuffer::create_uninitialized(SANDBOX_CANARY_SIZE + testcase.dest_n + SANDBOX_CANARY_SIZE).release_value();
-    fill_with_random(actual.data(), actual.size());
+    fill_with_random(actual);
     ByteBuffer expected = actual;
     VERIFY(actual.offset_pointer(0) != expected.offset_pointer(0));
     actual.overwrite(SANDBOX_CANARY_SIZE, testcase.dest, testcase.dest_n);

Tests/LibCompress/TestDeflate.cpp

@@ -115,7 +115,7 @@ TEST_CASE(deflate_decompress_zeroes)
 TEST_CASE(deflate_round_trip_store)
 {
     auto original = ByteBuffer::create_uninitialized(1024).release_value();
-    fill_with_random(original.data(), 1024);
+    fill_with_random(original);
     auto compressed = Compress::DeflateCompressor::compress_all(original, Compress::DeflateCompressor::CompressionLevel::STORE);
     EXPECT(!compressed.is_error());
     auto uncompressed = Compress::DeflateDecompressor::decompress_all(compressed.value());
@@ -126,7 +126,7 @@ TEST_CASE(deflate_round_trip_store)
 TEST_CASE(deflate_round_trip_compress)
 {
     auto original = ByteBuffer::create_zeroed(2048).release_value();
-    fill_with_random(original.data(), 1024); // we pre-filled the second half with 0s to make sure we test back references as well
+    fill_with_random(original.bytes().trim(1024)); // we pre-filled the second half with 0s to make sure we test back references as well
     // Since the different levels just change how much time is spent looking for better matches, just use fast here to reduce test time
     auto compressed = Compress::DeflateCompressor::compress_all(original, Compress::DeflateCompressor::CompressionLevel::FAST);
     EXPECT(!compressed.is_error());
@@ -139,7 +139,7 @@ TEST_CASE(deflate_round_trip_compress_large)
 {
     auto size = Compress::DeflateCompressor::block_size * 2;
     auto original = ByteBuffer::create_uninitialized(size).release_value(); // Compress a buffer larger than the maximum block size to test the sliding window mechanism
-    fill_with_random(original.data(), size);
+    fill_with_random(original);
     // Since the different levels just change how much time is spent looking for better matches, just use fast here to reduce test time
     auto compressed = Compress::DeflateCompressor::compress_all(original, Compress::DeflateCompressor::CompressionLevel::FAST);
     EXPECT(!compressed.is_error());

Tests/LibCompress/TestGzip.cpp

@@ -88,7 +88,7 @@ TEST_CASE(gzip_decompress_repeat_around_buffer)
 TEST_CASE(gzip_round_trip)
 {
     auto original = ByteBuffer::create_uninitialized(1024).release_value();
-    fill_with_random(original.data(), 1024);
+    fill_with_random(original);
     auto compressed = Compress::GzipCompressor::compress_all(original);
     EXPECT(!compressed.is_error());
     auto uncompressed = Compress::GzipDecompressor::decompress_all(compressed.value());

Tests/LibCrypto/TestBigInteger.cpp

@@ -398,7 +398,7 @@ TEST_CASE(test_bigint_import_big_endian_decode_encode_roundtrip)
 {
     u8 random_bytes[128];
     u8 target_buffer[128];
-    fill_with_random(random_bytes, 128);
+    fill_with_random(random_bytes);
     auto encoded = Crypto::UnsignedBigInteger::import_data(random_bytes, 128);
     encoded.export_data({ target_buffer, 128 });
     EXPECT(memcmp(target_buffer, random_bytes, 128) == 0);

Userland/Libraries/LibCore/Account.cpp

@@ -30,7 +30,7 @@ namespace Core {
 static DeprecatedString get_salt()
 {
     char random_data[12];
-    fill_with_random(random_data, sizeof(random_data));
+    fill_with_random({ random_data, sizeof(random_data) });
 
     StringBuilder builder;
     builder.append("$5$"sv);

Userland/Libraries/LibCrypto/Curves/Ed25519.cpp

@@ -19,7 +19,7 @@ ErrorOr<ByteBuffer> Ed25519::generate_private_key()
     // about randomness.
 
     auto buffer = TRY(ByteBuffer::create_uninitialized(key_size()));
-    fill_with_random(buffer.data(), buffer.size());
+    fill_with_random(buffer);
     return buffer;
 };
 

Userland/Libraries/LibCrypto/Curves/SECP256r1.cpp

@@ -357,7 +357,7 @@ static bool is_point_on_curve(JacobianPoint const& point)
 ErrorOr<ByteBuffer> SECP256r1::generate_private_key()
 {
     auto buffer = TRY(ByteBuffer::create_uninitialized(32));
-    fill_with_random(buffer.data(), buffer.size());
+    fill_with_random(buffer);
     return buffer;
 }
 

Userland/Libraries/LibCrypto/Curves/X25519.cpp

@@ -30,7 +30,7 @@ static void conditional_swap(u32* first, u32* second, u32 condition)
 ErrorOr<ByteBuffer> X25519::generate_private_key()
 {
     auto buffer = TRY(ByteBuffer::create_uninitialized(BYTES));
-    fill_with_random(buffer.data(), buffer.size());
+    fill_with_random(buffer);
     return buffer;
 }
 

Userland/Libraries/LibCrypto/Curves/X448.cpp

@@ -291,7 +291,7 @@ static void modular_multiply_inverse(u32* state, u32* value)
 ErrorOr<ByteBuffer> X448::generate_private_key()
 {
     auto buffer = TRY(ByteBuffer::create_uninitialized(BYTES));
-    fill_with_random(buffer.data(), buffer.size());
+    fill_with_random(buffer);
     return buffer;
 }
 

Userland/Libraries/LibCrypto/NumberTheory/ModularFunctions.cpp

@@ -168,7 +168,7 @@ UnsignedBigInteger random_number(UnsignedBigInteger const& min, UnsignedBigInteg
     auto buffer = ByteBuffer::create_uninitialized(size).release_value_but_fixme_should_propagate_errors(); // FIXME: Handle possible OOM situation.
     auto* buf = buffer.data();
 
-    fill_with_random(buf, size);
+    fill_with_random(buffer);
     UnsignedBigInteger random { buf, size };
     // At this point, `random` is a large number, in the range [0, 256^size).
     // To get down to the actual range, we could just compute random % range.

Userland/Libraries/LibCrypto/PK/Code/EMSA_PSS.h

@@ -39,7 +39,7 @@ public:
         auto em_length = (em_bits + 7) / 8;
         u8 salt[SaltLength];
 
-        fill_with_random(salt, SaltLength);
+        fill_with_random(salt);
 
         if (em_length < hash_length + SaltLength + 2) {
             dbgln("Ooops...encoding error");

Userland/Libraries/LibCrypto/PK/RSA.cpp

@@ -343,12 +343,13 @@ void RSA_PKCS1_EME::encrypt(ReadonlyBytes in, Bytes& out)
     Vector<u8, 8096> ps;
     ps.resize(ps_length);
 
-    fill_with_random(ps.data(), ps_length);
+    fill_with_random(ps);
     // since fill_with_random can create zeros (shocking!)
     // we have to go through and un-zero the zeros
-    for (size_t i = 0; i < ps_length; ++i)
+    for (size_t i = 0; i < ps_length; ++i) {
         while (!ps[i])
-            fill_with_random(ps.span().offset(i), 1);
+            ps[i] = get_random<u8>();
+    }
 
     u8 paddings[] { 0x00, 0x02 };
 

Userland/Libraries/LibTLS/Handshake.cpp

@@ -18,7 +18,7 @@ namespace TLS {
 
 ByteBuffer TLSv12::build_hello()
 {
-    fill_with_random(&m_context.local_random, 32);
+    fill_with_random(m_context.local_random);
 
     auto packet_version = (u16)m_context.options.version;
     auto version = (u16)m_context.options.version;

Userland/Libraries/LibTLS/HandshakeClient.cpp

@@ -157,7 +157,7 @@ void TLSv12::build_rsa_pre_master_secret(PacketBuilder& builder)
     u8 random_bytes[48];
     size_t bytes = 48;
 
-    fill_with_random(random_bytes, bytes);
+    fill_with_random(random_bytes);
 
     // remove zeros from the random bytes
     for (size_t i = 0; i < bytes; ++i) {

Userland/Libraries/LibTLS/Record.cpp

@@ -159,7 +159,7 @@ void TLSv12::update_packet(ByteBuffer& packet)
                         u8 iv[16];
                         Bytes iv_bytes { iv, 16 };
                         Bytes { m_context.crypto.local_aead_iv, 4 }.copy_to(iv_bytes);
-                        fill_with_random(iv_bytes.offset(4), 8);
+                        fill_with_random(iv_bytes.slice(4, 8));
                         memset(iv_bytes.offset(12), 0, 4);
 
                         // write the random part of the iv out
@@ -207,7 +207,7 @@ void TLSv12::update_packet(ByteBuffer& packet)
                             VERIFY_NOT_REACHED();
                         }
                         auto iv = iv_buffer_result.release_value();
-                        fill_with_random(iv.data(), iv.size());
+                        fill_with_random(iv);
 
                         // write it into the ciphertext portion of the message
                         ct.overwrite(header_size, iv.data(), iv.size());

Userland/Libraries/LibWeb/Crypto/Crypto.cpp

@@ -61,7 +61,7 @@ WebIDL::ExceptionOr<JS::Value> Crypto::get_random_values(JS::Value array) const
     // FIXME: Handle SharedArrayBuffers
 
     // 3. Overwrite all elements of array with cryptographically strong random values of the appropriate type.
-    fill_with_random(typed_array.viewed_array_buffer()->buffer().data(), typed_array.viewed_array_buffer()->buffer().size());
+    fill_with_random(typed_array.viewed_array_buffer()->buffer());
 
     // 4. Return array.
     return array;
@@ -88,7 +88,7 @@ ErrorOr<String> generate_random_uuid()
     u8 bytes[16];
 
     // 2. Fill bytes with cryptographically secure random bytes.
-    fill_with_random(bytes, 16);
+    fill_with_random(bytes);
 
     // 3. Set the 4 most significant bits of bytes[6], which represent the UUID version, to 0100.
     bytes[6] &= ~(1 << 7);

Userland/Libraries/LibWebSocket/WebSocket.cpp

@@ -184,7 +184,7 @@ void WebSocket::send_client_handshake()
 
     // 7. 16-byte nonce encoded as Base64
     u8 nonce_data[16];
-    fill_with_random(nonce_data, 16);
+    fill_with_random(nonce_data);
     // FIXME: change to TRY() and make method fallible
     m_websocket_key = MUST(encode_base64({ nonce_data, 16 })).to_deprecated_string();
     builder.appendff("Sec-WebSocket-Key: {}\r\n", m_websocket_key);
@@ -579,7 +579,7 @@ void WebSocket::send_frame(WebSocket::OpCode op_code, ReadonlyBytes payload, boo
         // > Clients MUST choose a new masking key for each frame, using an algorithm
         // > that cannot be predicted by end applications that provide data
         u8 masking_key[4];
-        fill_with_random(masking_key, 4);
+        fill_with_random(masking_key);
         m_impl->send(ReadonlyBytes(masking_key, 4));
         // don't try to send empty payload
         if (payload.size() == 0)

Userland/Utilities/useradd.cpp

@@ -136,7 +136,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     auto get_salt = []() -> ErrorOr<DeprecatedString> {
         char random_data[12];
-        fill_with_random(random_data, sizeof(random_data));
+        fill_with_random({ random_data, sizeof(random_data) });
 
         StringBuilder builder;
         builder.append("$5$"sv);