molly-brown/dynamic.go

163 lines
4.3 KiB
Go

package main
import (
"bufio"
"context"
"crypto/tls"
"io"
"net"
"net/url"
"os"
"os/exec"
"strconv"
"strings"
"time"
)
func handleCGI(config Config, path string, URL *url.URL, log *LogEntry, errorLog chan string, conn net.Conn) {
// Make sure file is executable
info, err := os.Stat(path)
if info.Mode().Perm()&0111 != 0111 {
return
}
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
cmd := exec.CommandContext(ctx, path)
// Set environment variables
vars := prepareCGIVariables(config, URL, conn, path)
cmd.Env = []string{}
for key, value := range vars {
cmd.Env = append(cmd.Env, key+"="+value)
}
response, err := cmd.Output()
if ctx.Err() == context.DeadlineExceeded {
errorLog <- "Terminating CGI process " + path + " due to exceeding 10 second runtime limit."
conn.Write([]byte("42 CGI process timed out!\r\n"))
log.Status = 42
return
}
if err != nil {
errorLog <- "Error starting CGI executable " + path + ": " + err.Error()
conn.Write([]byte("42 CGI error!\r\n"))
log.Status = 42
return
}
// Extract response header
header, _, err := bufio.NewReader(strings.NewReader(string(response))).ReadLine()
status, err2 := strconv.Atoi(strings.Fields(string(header))[0])
if err != nil || err2 != nil {
errorLog <- "Unable to parse first line of output from CGI process " + path + " as valid Gemini response header."
conn.Write([]byte("42 CGI error!\r\n"))
log.Status = 42
return
}
log.Status = status
// Write response
conn.Write(response)
}
func handleSCGI(socket_path string, config Config, URL *url.URL, log *LogEntry, conn net.Conn) {
// Connect to socket
socket, err := net.Dial("unix", socket_path)
if err != nil {
conn.Write([]byte("42 Error connecting to SCGI service!\r\n"))
log.Status = 42
return
}
defer socket.Close()
// Send variables
vars := prepareSCGIVariables(config, URL, conn)
length := 0
for key, value := range vars {
length += len(key)
length += len(value)
length += 2
}
socket.Write([]byte(strconv.Itoa(length) + ":"))
for key, value := range vars {
socket.Write([]byte(key + "\x00"))
socket.Write([]byte(value + "\x00"))
}
socket.Write([]byte(","))
// Read and relay response
buffer := make([]byte, 1027)
first := true
for {
n, err := socket.Read(buffer)
if err != nil {
if err == io.EOF {
break
} else if !first {
// Err
conn.Write([]byte("42 Error reading from SCGI service!\r\n"))
log.Status = 42
return
} else {
break
}
}
// Extract status code from first line
if first {
first = false
lines := strings.SplitN(string(buffer), "\r\n", 2)
status, err := strconv.Atoi(strings.Fields(lines[0])[0])
if err != nil {
conn.Write([]byte("42 CGI error!\r\n"))
log.Status = 42
return
}
log.Status = status
}
// Send to client
conn.Write(buffer[:n])
}
}
func prepareCGIVariables(config Config, URL *url.URL, conn net.Conn, path string) map[string]string {
vars := prepareGatewayVariables(config, URL, conn)
vars["GATEWAY_INTERFACE"] = "CGI/1.1"
vars["SCRIPT_PATH"] = path
return vars
}
func prepareSCGIVariables(config Config, URL *url.URL, conn net.Conn) map[string]string {
vars := prepareGatewayVariables(config, URL, conn)
vars["SCGI"] = "1"
vars["CONTENT_LENGTH"] = "0"
return vars
}
func prepareGatewayVariables(config Config, URL *url.URL, conn net.Conn) map[string]string {
vars := make(map[string]string)
vars["PATH_INFO"] = "/"
vars["QUERY_STRING"] = URL.RawQuery
vars["REMOTE_ADDR"] = conn.RemoteAddr().String()
vars["REQUEST_METHOD"] = ""
vars["SERVER_NAME"] = config.Hostname
vars["SERVER_PORT"] = strconv.Itoa(config.Port)
vars["SERVER_PROTOCOL"] = "GEMINI"
vars["SERVER_SOFTWARE"] = "MOLLY_BROWN"
// Add TLS variables
var tlsConn (*tls.Conn) = conn.(*tls.Conn)
connState := tlsConn.ConnectionState()
// vars["TLS_CIPHER"] = CipherSuiteName(connState.CipherSuite)
// Add client cert variables
clientCerts := connState.PeerCertificates
if len(clientCerts) > 0 {
cert := clientCerts[0]
vars["TLS_CLIENT_HASH"] = getCertFingerprint(cert)
vars["TLS_CLIENT_ISSUER"] = cert.Issuer.String()
vars["TLS_CLIENT_ISSUER_CN"] = cert.Issuer.CommonName
vars["TLS_CLIENT_SUBJECT"] = cert.Subject.String()
vars["TLS_CLIENT_SUBJECT_CN"] = cert.Subject.CommonName
}
return vars
}