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Logging improvements:
- Add src_ip, src_port, dst_ip, dst_port to tlsparse error logs
- Add connection details to fingerprint error logs (conn_id, payload_len)
- Include 'unknown' placeholders for packets that fail before parsing
This helps debug issues with truncated ClientHello payloads
and identify problematic connections more easily.
Example log output:
WARN Failed to generate fingerprints
src_ip=192.168.1.10 src_port=54321 dst_ip=10.0.0.1 dst_port=443
conn_id=192.168.1.10:54321->10.0.0.1:443 payload_len=128
error="failed to parse ClientHello: extension data truncated"
Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>
Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>
70 lines
2.3 KiB
Go
70 lines
2.3 KiB
Go
// Package fingerprint provides JA4/JA3 fingerprint generation for TLS ClientHello
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package fingerprint
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import (
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"fmt"
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"ja4sentinel/api"
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tlsfingerprint "github.com/psanford/tlsfingerprint"
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)
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// EngineImpl implements the api.Engine interface for fingerprint generation
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type EngineImpl struct{}
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// NewEngine creates a new fingerprint engine
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func NewEngine() *EngineImpl {
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return &EngineImpl{}
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}
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// FromClientHello generates JA4 (and optionally JA3) fingerprints from a TLS ClientHello
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// Note: JA4 hash portion is extracted for internal use but NOT serialized to LogRecord
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// as the JA4 format already includes its own hash portions (per architecture.yml)
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func (e *EngineImpl) FromClientHello(ch api.TLSClientHello) (*api.Fingerprints, error) {
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if len(ch.Payload) == 0 {
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return nil, fmt.Errorf("empty ClientHello payload from %s:%d -> %s:%d",
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ch.SrcIP, ch.SrcPort, ch.DstIP, ch.DstPort)
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}
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// Parse the ClientHello using tlsfingerprint
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fp, err := tlsfingerprint.ParseClientHello(ch.Payload)
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if err != nil {
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return nil, fmt.Errorf("failed to parse ClientHello from %s:%d -> %s:%d (conn_id=%s, payload_len=%d): %w",
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ch.SrcIP, ch.SrcPort, ch.DstIP, ch.DstPort, ch.ConnID, len(ch.Payload), err)
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}
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// Generate JA4 fingerprint
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// Note: JA4 string format already includes the hash portion
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// e.g., "t13d1516h2_8daaf6152771_02cb136f2775" where the last part is the SHA256 hash
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ja4 := fp.JA4String()
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// Generate JA3 fingerprint and its MD5 hash
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ja3 := fp.JA3String()
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ja3Hash := fp.JA3Hash()
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// Extract JA4 hash portion (last segment after underscore)
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// JA4 format: <tls_ver><ciphers><extensions>_<sni_hash>_<cipher_extension_hash>
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// This is kept for internal use but NOT serialized to LogRecord
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ja4Hash := extractJA4Hash(ja4)
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return &api.Fingerprints{
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JA4: ja4,
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JA4Hash: ja4Hash, // Internal use only - not serialized to LogRecord
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JA3: ja3,
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JA3Hash: ja3Hash,
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}, nil
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}
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// extractJA4Hash extracts the hash portion from a JA4 string
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// JA4 format: <base>_<sni_hash>_<cipher_hash> -> returns "<sni_hash>_<cipher_hash>"
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func extractJA4Hash(ja4 string) string {
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// JA4 string format: t13d1516h2_8daaf6152771_02cb136f2775
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// We extract everything after the first underscore as the "hash" portion
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for i, c := range ja4 {
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if c == '_' {
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return ja4[i+1:]
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}
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}
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return ""
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}
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