From 83e9585d06d86019b54a4dd117422ba9c2506a57 Mon Sep 17 00:00:00 2001
From: 688862 <96077242+688862@users.noreply.github.com>
Date: Sat, 8 Jan 2022 23:08:46 +0800
Subject: [PATCH] crypto: crypto.aes CBC mode moves to crypto.cipher (#13084)

---
 vlib/crypto/README.md             |   4 +-
 vlib/crypto/aes/aes.v             |  12 +--
 vlib/crypto/aes/aes_cbc.v         | 126 +-----------------------------
 vlib/crypto/aes/aes_test.v        |  27 +++----
 vlib/crypto/aes/cypher_generic.v  |   4 +-
 vlib/crypto/cipher/aes_cbc_test.v |  32 ++++++++
 6 files changed, 54 insertions(+), 151 deletions(-)
 create mode 100644 vlib/crypto/cipher/aes_cbc_test.v

diff --git a/vlib/crypto/README.md b/vlib/crypto/README.md
index 829ae1b902..09a30e586c 100644
--- a/vlib/crypto/README.md
+++ b/vlib/crypto/README.md
@@ -32,12 +32,12 @@ fn main() {
 
 	println('performing encryption')
 	mut encrypted := []byte{len: aes.block_size}
-	cipher.encrypt(mut encrypted, mut data)
+	cipher.encrypt(mut encrypted, data)
 	println(encrypted)
 
 	println('performing decryption')
 	mut decrypted := []byte{len: aes.block_size}
-	cipher.decrypt(mut decrypted, mut encrypted)
+	cipher.decrypt(mut decrypted, encrypted)
 	println(decrypted)
 
 	assert decrypted == data
diff --git a/vlib/crypto/aes/aes.v b/vlib/crypto/aes/aes.v
index b023b8f04a..5c4bc45b69 100644
--- a/vlib/crypto/aes/aes.v
+++ b/vlib/crypto/aes/aes.v
@@ -5,6 +5,7 @@
 // Last commit: https://github.com/golang/go/commit/691a2d457ab1bf03bd46d4b69e0f93b8993c0055
 module aes
 
+import crypto.cipher
 import crypto.internal.subtle
 
 pub const (
@@ -17,6 +18,7 @@ pub const (
 // handle only one block of data at a time. In most cases, you
 // probably want to encrypt and decrypt using [[AesCbc](#AesCbc)]
 struct AesCipher {
+	block_size int = aes.block_size
 mut:
 	enc []u32
 	dec []u32
@@ -26,7 +28,7 @@ mut:
 // The key argument should be the AES key,
 // either 16, 24, or 32 bytes to select
 // AES-128, AES-192, or AES-256.
-pub fn new_cipher(key []byte) AesCipher {
+pub fn new_cipher(key []byte) cipher.Block {
 	k := key.len
 	match k {
 		16, 24, 32 {
@@ -50,7 +52,7 @@ pub fn (c &AesCipher) block_size() int {
 // NOTE: `dst` and `src` are both mutable for performance reasons.
 // NOTE: `dst` and `src` must both be pre-allocated to the correct length.
 // NOTE: `dst` and `src` may be the same (overlapping entirely).
-pub fn (c &AesCipher) encrypt(mut dst []byte, mut src []byte) {
+pub fn (c &AesCipher) encrypt(mut dst []byte, src []byte) {
 	if src.len < aes.block_size {
 		panic('crypto.aes: input not full block')
 	}
@@ -58,7 +60,7 @@ pub fn (c &AesCipher) encrypt(mut dst []byte, mut src []byte) {
 		panic('crypto.aes: output not full block')
 	}
 	// if subtle.inexact_overlap(dst[:block_size], src[:block_size]) {
-	if subtle.inexact_overlap((*dst)[..aes.block_size], (*src)[..aes.block_size]) {
+	if subtle.inexact_overlap(dst[..aes.block_size], src[..aes.block_size]) {
 		panic('crypto.aes: invalid buffer overlap')
 	}
 	// for now use generic version
@@ -69,14 +71,14 @@ pub fn (c &AesCipher) encrypt(mut dst []byte, mut src []byte) {
 // NOTE: `dst` and `src` are both mutable for performance reasons.
 // NOTE: `dst` and `src` must both be pre-allocated to the correct length.
 // NOTE: `dst` and `src` may be the same (overlapping entirely).
-pub fn (c &AesCipher) decrypt(mut dst []byte, mut src []byte) {
+pub fn (c &AesCipher) decrypt(mut dst []byte, src []byte) {
 	if src.len < aes.block_size {
 		panic('crypto.aes: input not full block')
 	}
 	if dst.len < aes.block_size {
 		panic('crypto.aes: output not full block')
 	}
-	if subtle.inexact_overlap((*dst)[..aes.block_size], (*src)[..aes.block_size]) {
+	if subtle.inexact_overlap(dst[..aes.block_size], src[..aes.block_size]) {
 		panic('crypto.aes: invalid buffer overlap')
 	}
 	// for now use generic version
diff --git a/vlib/crypto/aes/aes_cbc.v b/vlib/crypto/aes/aes_cbc.v
index f2e69b995f..74137a4d28 100644
--- a/vlib/crypto/aes/aes_cbc.v
+++ b/vlib/crypto/aes/aes_cbc.v
@@ -1,126 +1,2 @@
-// Copyright (c) 2019-2022 Alexander Medvednikov. All rights reserved.
-// Use of this source code is governed by an MIT license
-// that can be found in the LICENSE file.
-// Cipher block chaining (CBC) mode.
-// CBC provides confidentiality by xoring (chaining) each plaintext block
-// with the previous ciphertext block before applying the block cipher.
-// See NIST SP 800-38A, pp 10-11
-// NOTE this will be moved to crypto.cipher interface (joe-c)
+// CBC mode has been moved to crypto.cipher
 module aes
-
-import crypto.cipher
-import crypto.internal.subtle
-
-struct AesCbc {
-mut:
-	b          AesCipher
-	block_size int
-	iv         []byte
-	tmp        []byte
-}
-
-// internal
-fn new_aes_cbc(b AesCipher, iv []byte) AesCbc {
-	return AesCbc{
-		b: b
-		block_size: b.block_size()
-		iv: iv.clone()
-		tmp: []byte{len: (b.block_size())}
-	}
-}
-
-// new_cbc returns a `AesCbc` which encrypts in cipher block chaining
-// mode, using the given Block. The length of iv must be the same as the
-// Block's block size.
-pub fn new_cbc(b AesCipher, iv []byte) AesCbc {
-	if iv.len != b.block_size() {
-		panic('crypto.cipher.new_cbc_encrypter: IV length must equal block size')
-	}
-	return new_aes_cbc(b, iv)
-}
-
-// block_size returns the block size of the checksum in bytes.
-pub fn (x &AesCbc) block_size() int {
-	return x.block_size
-}
-
-// encrypt_blocks encrypts the blocks in `src_` to `dst_`.
-// Please note: `dst_` is mutable for performance reasons.
-pub fn (x &AesCbc) encrypt_blocks(mut dst_ []byte, src_ []byte) {
-	unsafe {
-		mut dst := *dst_
-		mut src := src_
-		if src.len % x.block_size != 0 {
-			panic('crypto.cipher: input not full blocks')
-		}
-		if dst.len < src.len {
-			panic('crypto.cipher: output smaller than input')
-		}
-		if subtle.inexact_overlap(dst[..src.len], src_) {
-			panic('crypto.cipher: invalid buffer overlap')
-		}
-		mut iv := x.iv
-		for src.len > 0 {
-			// Write the xor to dst, then encrypt in place.
-			cipher.xor_bytes(mut dst[..x.block_size], src[..x.block_size], iv)
-			x.b.encrypt(mut dst[..x.block_size], mut dst[..x.block_size])
-			// Move to the next block with this block as the next iv.
-			iv = dst[..x.block_size]
-			if x.block_size >= src.len {
-				src = []
-			} else {
-				src = src[x.block_size..]
-			}
-			dst = dst[x.block_size..]
-		}
-		// Save the iv for the next crypt_blocks call.
-		copy(x.iv, iv)
-	}
-}
-
-// decrypt_blocks decrypts the blocks in `src` to `dst`.
-// Please note: `dst` is mutable for performance reasons.
-pub fn (mut x AesCbc) decrypt_blocks(mut dst []byte, src []byte) {
-	if src.len % x.block_size != 0 {
-		panic('crypto.cipher: input not full blocks')
-	}
-	if dst.len < src.len {
-		panic('crypto.cipher: output smaller than input')
-	}
-	if subtle.inexact_overlap((*dst)[..src.len], src) {
-		panic('crypto.cipher: invalid buffer overlap')
-	}
-	if src.len == 0 {
-		return
-	}
-	// For each block, we need to xor the decrypted data with the previous block's ciphertext (the iv).
-	// To avoid making a copy each time, we loop over the blocks BACKWARDS.
-	mut end := src.len
-	mut start := end - x.block_size
-	mut prev := start - x.block_size
-	// Copy the last block of ciphertext in preparation as the new iv.
-	copy(x.tmp, src[start..end])
-	// Loop over all but the first block.
-	for start > 0 {
-		mut src_chunk := src[start..end]
-		x.b.decrypt(mut (*dst)[start..end], mut src_chunk)
-		cipher.xor_bytes(mut (*dst)[start..end], (*dst)[start..end], src[prev..start])
-		end = start
-		start = prev
-		prev -= x.block_size
-	}
-	// The first block is special because it uses the saved iv.
-	mut src_chunk := src[start..end]
-	x.b.decrypt(mut (*dst)[start..end], mut src_chunk)
-	cipher.xor_bytes(mut (*dst)[start..end], (*dst)[start..end], x.iv)
-	// Set the new iv to the first block we copied earlier.
-	x.iv = x.tmp
-	x.tmp = x.iv
-}
-
-fn (x &AesCbc) set_iv(iv []byte) {
-	if iv.len != x.iv.len {
-		panic('cipher: incorrect length IV')
-	}
-	copy(x.iv, iv)
-}
diff --git a/vlib/crypto/aes/aes_test.v b/vlib/crypto/aes/aes_test.v
index 34c788335c..a676044c95 100644
--- a/vlib/crypto/aes/aes_test.v
+++ b/vlib/crypto/aes/aes_test.v
@@ -3,25 +3,16 @@
 // that can be found in the LICENSE file.
 import crypto.aes
 
-fn test_crypto_aes() {
-	// TEST CBC
+fn test_aes() {
 	key := '6368616e676520746869732070617373'.bytes()
 	mut ciphertext := '73c86d43a9d700a253a96c85b0f6b03ac9792e0e757f869cca306bd3cba1c62b'.bytes()
 	block := aes.new_cipher(key)
-	// The IV needs to be unique, but not secure. Therefore it's common to
-	// include it at the beginning of the ciphertext.
-	if ciphertext.len < aes.block_size {
-		panic('ciphertext too short')
-	}
-	iv := ciphertext[..aes.block_size]
-	ciphertext = ciphertext[aes.block_size..]
-	// CBC mode always works in whole blocks.
-	if ciphertext.len % aes.block_size != 0 {
-		panic('ciphertext is not a multiple of the block size')
-	}
-	mode := aes.new_cbc(block, iv)
-	cipher_clone := ciphertext.clone()
-	mode.encrypt_blocks(mut ciphertext, cipher_clone)
-	assert ciphertext.hex() == 'c210459b514668ddc44674885e4979215265a6c44431a248421254ef357a8c2a308a8bddf5623af9df91737562041cf1'
-	println('ok')
+
+	block.encrypt(mut ciphertext, ciphertext.clone())
+	assert ciphertext.hex() == '05d1737fe0a7c12088ff4c94d62ccbd9353361393663383562306636623033616339373932653065373537663836396363613330366264336362613163363262'
+
+	block.decrypt(mut ciphertext, ciphertext.clone())
+
+	assert ciphertext.bytestr() == '73c86d43a9d700a253a96c85b0f6b03ac9792e0e757f869cca306bd3cba1c62b'
+	println('test_aes ok')
 }
diff --git a/vlib/crypto/aes/cypher_generic.v b/vlib/crypto/aes/cypher_generic.v
index 19efa7a1d6..e4ef590c40 100644
--- a/vlib/crypto/aes/cypher_generic.v
+++ b/vlib/crypto/aes/cypher_generic.v
@@ -3,9 +3,11 @@
 // that can be found in the LICENSE file.
 module aes
 
+import crypto.cipher
+
 // new_cipher_generic creates and returns a new cipher.Block
 // this is the generiv v version, no arch optimisations
-fn new_cipher_generic(key []byte) AesCipher {
+fn new_cipher_generic(key []byte) cipher.Block {
 	n := key.len + 28
 	mut c := AesCipher{
 		enc: []u32{len: n}
diff --git a/vlib/crypto/cipher/aes_cbc_test.v b/vlib/crypto/cipher/aes_cbc_test.v
new file mode 100644
index 0000000000..1c5071e7c4
--- /dev/null
+++ b/vlib/crypto/cipher/aes_cbc_test.v
@@ -0,0 +1,32 @@
+// Copyright (c) 2019-2022 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+import crypto.aes
+import crypto.cipher
+
+fn test_aes_cbc() {
+	key := '6368616e676520746869732070617373'.bytes()
+	iv := '1234567890123456'.bytes()
+	str := '73c86d43a9d700a253a96c85b0f6b03ac9792e0e757f869cca306bd3cba1c62b'
+
+	mut src := str.bytes()
+
+	aes_cbc_en(mut src, key, iv)
+	assert src.hex() == '20f36e39e6b73a040d3d39445d0282369033693076d1129a68a3364c00a81c508ec06ab94ff5104c321939fbfb9313c549fd68df100a8a23e8006a863733a8fd'
+
+	aes_cbc_de(mut src, key, iv)
+	assert src.bytestr() == str
+	println('test_aes_cbc ok')
+}
+
+fn aes_cbc_en(mut src []byte, key []byte, iv []byte) {
+	block := aes.new_cipher(key)
+	mode := cipher.new_cbc(block, iv)
+	mode.encrypt_blocks(mut src, src.clone())
+}
+
+fn aes_cbc_de(mut src []byte, key []byte, iv []byte) {
+	block := aes.new_cipher(key)
+	mut mode := cipher.new_cbc(block, iv)
+	mode.decrypt_blocks(mut src, src.clone())
+}