Ivan
5e0c829cf6
- **pkg/announce/announce.go**: Added error handling for `rand.Read` to log potential issues when generating random hashes. - **pkg/buffer/buffer.go**: Removed a redundant `#nosec G115` comment as the line no longer triggers the warning. - **pkg/cryptography/aes.go**: Added `#nosec G407` to explicitly acknowledge the use of `cipher.NewCBCEncrypter` which is acceptable in this context. - **pkg/transport/transport.go**: Removed redundant `#nosec G115` comments as the lines no longer trigger the warning.
111 lines
2.8 KiB
Go
111 lines
2.8 KiB
Go
package cryptography
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"errors"
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"io"
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)
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const (
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// AES256KeySize is the size of an AES-256 key in bytes.
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AES256KeySize = 32 // 256 bits
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)
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// GenerateAES256Key generates a random AES-256 key.
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func GenerateAES256Key() ([]byte, error) {
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key := make([]byte, AES256KeySize)
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if _, err := io.ReadFull(rand.Reader, key); err != nil {
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return nil, err
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}
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return key, nil
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}
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// EncryptAES256CBC encrypts data using AES-256 in CBC mode.
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// The IV is prepended to the ciphertext.
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func EncryptAES256CBC(key, plaintext []byte) ([]byte, error) {
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if len(key) != AES256KeySize {
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return nil, errors.New("invalid key size: must be 32 bytes for AES-256")
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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// Generate a random IV.
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iv := make([]byte, aes.BlockSize)
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if _, err := io.ReadFull(rand.Reader, iv); err != nil {
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return nil, err
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}
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// Add PKCS7 padding.
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padding := aes.BlockSize - len(plaintext)%aes.BlockSize
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padtext := make([]byte, len(plaintext)+padding)
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copy(padtext, plaintext)
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for i := len(plaintext); i < len(padtext); i++ {
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padtext[i] = byte(padding)
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}
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// Encrypt the data.
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mode := cipher.NewCBCEncrypter(block, iv) // #nosec G407
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ciphertext := make([]byte, len(padtext))
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mode.CryptBlocks(ciphertext, padtext)
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// Prepend the IV to the ciphertext.
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return append(iv, ciphertext...), nil
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}
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// DecryptAES256CBC decrypts data using AES-256 in CBC mode.
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// It assumes the IV is prepended to the ciphertext.
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func DecryptAES256CBC(key, ciphertext []byte) ([]byte, error) {
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if len(key) != AES256KeySize {
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return nil, errors.New("invalid key size: must be 32 bytes for AES-256")
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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if len(ciphertext) < aes.BlockSize {
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return nil, errors.New("ciphertext is too short")
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}
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// Extract the IV from the beginning of the ciphertext.
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iv := ciphertext[:aes.BlockSize]
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ciphertext = ciphertext[aes.BlockSize:]
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if len(ciphertext)%aes.BlockSize != 0 {
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return nil, errors.New("ciphertext is not a multiple of the block size")
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}
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// Decrypt the data.
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mode := cipher.NewCBCDecrypter(block, iv)
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plaintext := make([]byte, len(ciphertext))
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mode.CryptBlocks(plaintext, ciphertext)
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// Remove PKCS7 padding.
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if len(plaintext) == 0 {
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return nil, errors.New("invalid padding: plaintext is empty")
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}
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padding := int(plaintext[len(plaintext)-1])
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if padding > aes.BlockSize || padding == 0 {
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return nil, errors.New("invalid padding size")
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}
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if len(plaintext) < padding {
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return nil, errors.New("invalid padding: padding size is larger than plaintext")
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}
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// Verify the padding bytes.
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for i := len(plaintext) - padding; i < len(plaintext); i++ {
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if plaintext[i] != byte(padding) {
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return nil, errors.New("invalid padding bytes")
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}
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}
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return plaintext[:len(plaintext)-padding], nil
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}
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