LibCrypto: Add support for the POSIX cksum algorithm

Author: https://github.com/implicitfield
Commit: https://github.com/SerenityOS/serenity/commit/05ee5ffa36
Pull-request: https://github.com/SerenityOS/serenity/pull/22831
Issue: https://github.com/SerenityOS/serenity/issues/22795
Reviewed-by: https://github.com/alimpfard

Tests/LibCrypto/TestChecksum.cpp

@@ -6,6 +6,7 @@
 
 #include <LibCrypto/Checksum/Adler32.h>
 #include <LibCrypto/Checksum/CRC32.h>
+#include <LibCrypto/Checksum/cksum.h>
 #include <LibTest/TestCase.h>
 
 TEST_CASE(test_adler32)
@@ -22,6 +23,35 @@ TEST_CASE(test_adler32)
     do_test(ByteString("abcdefghijklmnopqrstuvwxyz").bytes(), 0x90860b20);
 }
 
+TEST_CASE(test_cksum)
+{
+    auto do_test = [](ReadonlyBytes input, u32 expected_result) {
+        auto digest = Crypto::Checksum::cksum(input).digest();
+        EXPECT_EQ(digest, expected_result);
+    };
+
+    do_test(ByteString("").bytes(), 0xFFFFFFFF);
+    do_test(ByteString("The quick brown fox jumps over the lazy dog").bytes(), 0x7BAB9CE8);
+    do_test(ByteString("various CRC algorithms input data").bytes(), 0xEFB5CA4F);
+}
+
+TEST_CASE(test_cksum_atomic_digest)
+{
+    auto compare = [](u32 digest, u32 expected_result) {
+        EXPECT_EQ(digest, expected_result);
+    };
+
+    Crypto::Checksum::cksum cksum;
+
+    cksum.update(ByteString("Well").bytes());
+    cksum.update(ByteString(" hello ").bytes());
+    cksum.digest();
+    cksum.update(ByteString("friends").bytes());
+    auto digest = cksum.digest();
+
+    compare(digest, 0x2D65C7E0);
+}
+
 TEST_CASE(test_crc32)
 {
     auto do_test = [](ReadonlyBytes input, u32 expected_result) {

Userland/Libraries/LibCrypto/CMakeLists.txt

@@ -18,6 +18,7 @@ set(SOURCES
     BigInt/SignedBigInteger.cpp
     BigInt/UnsignedBigInteger.cpp
     Checksum/Adler32.cpp
+    Checksum/cksum.cpp
     Checksum/CRC32.cpp
     Cipher/AES.cpp
     Cipher/ChaCha20.cpp

Userland/Libraries/LibCrypto/Checksum/cksum.cpp

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2024, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibCrypto/Checksum/cksum.h>
+
+namespace Crypto::Checksum {
+
+static constexpr u32 table[256] = {
+    0x00000000,
+    0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
+    0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
+    0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
+    0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac,
+    0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f,
+    0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
+    0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
+    0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58,
+    0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033,
+    0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe,
+    0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
+    0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4,
+    0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
+    0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5,
+    0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
+    0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07,
+    0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c,
+    0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
+    0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b,
+    0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698,
+    0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d,
+    0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
+    0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f,
+    0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
+    0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
+    0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
+    0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a,
+    0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629,
+    0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c,
+    0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
+    0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e,
+    0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65,
+    0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8,
+    0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
+    0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2,
+    0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
+    0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74,
+    0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
+    0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21,
+    0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a,
+    0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087,
+    0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d,
+    0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce,
+    0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb,
+    0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
+    0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09,
+    0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
+    0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf,
+    0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
+};
+
+void cksum::update(ReadonlyBytes data)
+{
+    for (u8 byte : data)
+        m_state = (m_state << 8) ^ table[((m_state >> 24) ^ byte) & 0xFF];
+
+    m_size += data.size();
+}
+
+u32 cksum::digest()
+{
+    u32 size = m_size;
+    u32 state = m_state;
+
+    while (size) {
+        state = (state << 8) ^ table[((state >> 24) ^ size) & 0xFF];
+        size >>= 8;
+    }
+
+    state = ~state & 0xFFFFFFFF;
+    return state;
+}
+
+}

Userland/Libraries/LibCrypto/Checksum/cksum.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2024, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Span.h>
+#include <AK/Types.h>
+#include <LibCrypto/Checksum/ChecksumFunction.h>
+
+namespace Crypto::Checksum {
+
+class cksum : public ChecksumFunction<u32> {
+public:
+    cksum() = default;
+    cksum(ReadonlyBytes data)
+    {
+        update(data);
+    }
+
+    virtual void update(ReadonlyBytes data) override;
+    virtual u32 digest() override;
+
+private:
+    u32 m_state { 0 };
+    off_t m_size { 0 };
+};
+
+}