Files
ja4sentinel/internal/fingerprint/engine.go
Jacquin Antoine 965720a183
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release: version 1.0.9 - Add SNI, ALPN, TLS version extraction and architecture.yml compliance
New features:
- Extract SNI (Server Name Indication) from TLS ClientHello
- Extract ALPN (Application-Layer Protocol Negotiation) protocols
- Detect TLS version from ClientHello using tlsfingerprint library
- Add ConnID field for TCP flow correlation
- Add SensorID field for multi-sensor deployments
- Add SynToCHMs timing field for behavioral detection
- Add AsyncBuffer configuration for output queue sizing

Architecture changes:
- Remove JA4Hash from LogRecord (JA4 format includes its own hash portions)
- Update api.TLSClientHello with new TLS metadata fields
- Update api.LogRecord with correlation, TLS, and timing fields
- Ensure 100% compliance with architecture.yml specification

Tests:
- Add unit tests for TLS extension extraction (SNI, ALPN, Version)
- Update tests for new LogRecord schema without JA4Hash
- Add tests for AsyncBuffer configuration

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>
2026-03-02 19:32:16 +01:00

68 lines
2.1 KiB
Go

// Package fingerprint provides JA4/JA3 fingerprint generation for TLS ClientHello
package fingerprint
import (
"fmt"
"ja4sentinel/api"
tlsfingerprint "github.com/psanford/tlsfingerprint"
)
// EngineImpl implements the api.Engine interface for fingerprint generation
type EngineImpl struct{}
// NewEngine creates a new fingerprint engine
func NewEngine() *EngineImpl {
return &EngineImpl{}
}
// FromClientHello generates JA4 (and optionally JA3) fingerprints from a TLS ClientHello
// Note: JA4Hash is populated for internal use but should NOT be serialized to LogRecord
// as the JA4 format already includes its own hash portions (per architecture.yml)
func (e *EngineImpl) FromClientHello(ch api.TLSClientHello) (*api.Fingerprints, error) {
if len(ch.Payload) == 0 {
return nil, fmt.Errorf("empty ClientHello payload")
}
// Parse the ClientHello using tlsfingerprint
fp, err := tlsfingerprint.ParseClientHello(ch.Payload)
if err != nil {
return nil, fmt.Errorf("failed to parse ClientHello: %w", err)
}
// Generate JA4 fingerprint
// Note: JA4 string format already includes the hash portion
// e.g., "t13d1516h2_8daaf6152771_02cb136f2775" where the last part is the SHA256 hash
ja4 := fp.JA4String()
// Generate JA3 fingerprint and its MD5 hash
ja3 := fp.JA3String()
ja3Hash := fp.JA3Hash()
// Extract JA4 hash portion (last segment after underscore)
// JA4 format: <tls_ver><ciphers><extensions>_<sni_hash>_<cipher_extension_hash>
// This is kept for internal use but NOT serialized to LogRecord
ja4Hash := extractJA4Hash(ja4)
return &api.Fingerprints{
JA4: ja4,
JA4Hash: ja4Hash, // Internal use only - not serialized to LogRecord
JA3: ja3,
JA3Hash: ja3Hash,
}, nil
}
// extractJA4Hash extracts the hash portion from a JA4 string
// JA4 format: <base>_<sni_hash>_<cipher_hash> -> returns "<sni_hash>_<cipher_hash>"
func extractJA4Hash(ja4 string) string {
// JA4 string format: t13d1516h2_8daaf6152771_02cb136f2775
// We extract everything after the first underscore as the "hash" portion
for i, c := range ja4 {
if c == '_' {
return ja4[i+1:]
}
}
return ""
}