/
clamav.go
134 lines (119 loc) · 2.64 KB
/
clamav.go
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// http://www.clamav.net/doc/latest/clamdoc.pdf
package clamav
import (
"bufio"
"fmt"
"github.com/Polymail/go-falcon/config"
"io"
"net"
"regexp"
"strings"
)
const CHUNK_SIZE = 1024
var (
clamavRe = regexp.MustCompile(`(?i)^stream:([\s+]?)(.*)`)
)
type Clamav struct {
config *config.Config
RawEmail []byte
}
// check email for viruses by clamav
func CheckEmailForViruses(config *config.Config, email []byte) (string, error) {
clamav := &Clamav{
config: config,
RawEmail: email,
}
output, err := clamav.checkEmail()
if err != nil {
return "", err
}
return clamav.parseOutput(output), nil
}
// check email by clamav
func (ss *Clamav) checkEmail() ([]string, error) {
var dataArrays []string
conn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", ss.config.Clamav.Host, ss.config.Clamav.Port))
if err != nil {
return dataArrays, err
}
defer conn.Close()
// check email
if len(ss.RawEmail) <= 0 {
return dataArrays, nil
}
// write headers
_, err = conn.Write([]byte("nINSTREAM\n"))
if err != nil {
return dataArrays, err
}
chunkPos := 0
for {
if chunkPos+CHUNK_SIZE >= len(ss.RawEmail)-1 {
data := ss.RawEmail[chunkPos : len(ss.RawEmail)-1]
err = sendChunkOfData(conn, data)
if err != nil {
return dataArrays, err
}
break
} else {
data := ss.RawEmail[chunkPos : chunkPos+CHUNK_SIZE]
err = sendChunkOfData(conn, data)
if err != nil {
return dataArrays, err
}
chunkPos = chunkPos + CHUNK_SIZE + 1
}
}
// write end
_, err = conn.Write([]byte{0, 0, 0, 0})
if err != nil {
return dataArrays, err
}
// read data
reader := bufio.NewReader(conn)
// reading
for {
line, err := reader.ReadString('\n')
if err == io.EOF {
break
}
if err != nil {
return dataArrays, err
}
line = strings.TrimRight(line, " \t\r\n")
dataArrays = append(dataArrays, line)
}
return dataArrays, nil
}
// send data in chunks
func sendChunkOfData(conn net.Conn, data []byte) error {
lenData := len(data)
var buf [4]byte
buf[0] = byte(lenData >> 24)
buf[1] = byte(lenData >> 16)
buf[2] = byte(lenData >> 8)
buf[3] = byte(lenData >> 0)
dataWrite := []byte{}
dataWrite = append(dataWrite, buf[0], buf[1], buf[2], buf[3])
dataWrite = append(dataWrite, data...)
_, err := conn.Write(dataWrite)
return err
}
// parse clamav output
func (ss *Clamav) parseOutput(output []string) string {
result := strings.Join(output, ", ")
result = strings.Trim(result, " \t\r\n")
if clamavRe.MatchString(result) {
res := clamavRe.FindStringSubmatch(result)
if len(res) >= 2 {
if strings.ToLower(res[2]) == "ok" {
return ""
} else {
return res[2]
}
} else {
return ""
}
}
return ""
}