sniffer-agent/session-dealer/mysql/util.go

131 lines
3.5 KiB
Go

package mysql
import (
"bytes"
"encoding/binary"
)
// parseHandshakeResponseHeader parses the common header of SSLRequest and HandshakeResponse41.
func parseHandshakeResponseHeader(packet *handshakeResponse41, data []byte) (parsedBytes int, err error) {
// Ensure there are enough data to read:
// http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::SSLRequest
if len(data) < 4+4+1+23 {
return 0, ErrMalformPacket
}
offset := 0
// capability
capability := binary.LittleEndian.Uint32(data[:4])
packet.Capability = capability
offset += 4
// skip max packet size
offset += 4
// charset, skip, if you want to use another charset, use set names
packet.Collation = data[offset]
offset++
// skip reserved 23[00]
offset += 23
return offset, nil
}
// parseHandshakeResponseBody parse the HandshakeResponse (except the common header part).
func parseHandshakeResponseBody(packet *handshakeResponse41, data []byte, offset int) (err error) {
defer func() {
// Check malformat packet cause out of range is disgusting, but don't panic!
if r := recover(); r != nil {
err = ErrMalformPacket
}
}()
// user name
packet.User = string(data[offset : offset+bytes.IndexByte(data[offset:], 0)])
offset += len(packet.User) + 1
if packet.Capability&ClientPluginAuthLenencClientData > 0 {
// MySQL client sets the wrong capability, it will set this bit even server doesn't
// support ClientPluginAuthLenencClientData.
// https://github.com/mysql/mysql-server/blob/5.7/sql-common/client.c#L3478
num, null, off := parseLengthEncodedInt(data[offset:])
offset += off
if !null {
packet.Auth = data[offset : offset+int(num)]
offset += int(num)
}
} else if packet.Capability&ClientSecureConnection > 0 {
// auth length and auth
authLen := int(data[offset])
offset++
packet.Auth = data[offset : offset+authLen]
offset += authLen
} else {
packet.Auth = data[offset : offset+bytes.IndexByte(data[offset:], 0)]
offset += len(packet.Auth) + 1
}
if packet.Capability&ClientConnectWithDB > 0 {
if len(data[offset:]) > 0 {
idx := bytes.IndexByte(data[offset:], 0)
packet.DBName = string(data[offset : offset+idx])
offset = offset + idx + 1
}
}
if packet.Capability&ClientPluginAuth > 0 {
// TODO: Support mysql.ClientPluginAuth, skip it now
idx := bytes.IndexByte(data[offset:], 0)
offset = offset + idx + 1
}
if packet.Capability&ClientConnectAtts > 0 {
if len(data[offset:]) == 0 {
// Defend some ill-formated packet, connection attribute is not important and can be ignored.
return nil
}
}
return nil
}
func parseLengthEncodedInt(b []byte) (num uint64, isNull bool, n int) {
switch b[0] {
// 251: NULL
case 0xfb:
n = 1
isNull = true
return
// 252: value of following 2
case 0xfc:
num = uint64(b[1]) | uint64(b[2])<<8
n = 3
return
// 253: value of following 3
case 0xfd:
num = uint64(b[1]) | uint64(b[2])<<8 | uint64(b[3])<<16
n = 4
return
// 254: value of following 8
case 0xfe:
num = uint64(b[1]) | uint64(b[2])<<8 | uint64(b[3])<<16 |
uint64(b[4])<<24 | uint64(b[5])<<32 | uint64(b[6])<<40 |
uint64(b[7])<<48 | uint64(b[8])<<56
n = 9
return
}
// 0-250: value of first byte
num = uint64(b[0])
n = 1
return
}
func extractMysqlPayloadSize(payload []byte) int {
header := payload[:4]
return int(uint32(header[0]) | uint32(header[1])<<8 | uint32(header[2])<<16)
}
func bytesToInt(contents []byte) int {
return int(uint32(contents[0]) | uint32(contents[1])<<8 | uint32(contents[2])<<16 | uint32(contents[3])<<24)
}