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Extensive refactor, trying to keep the main request handling function relatively simple.

pull/12/head
Solderpunk 1 year ago
parent
commit
68398ef0be
  1. 63
      certificate.go
  2. 115
      dirlist.go
  3. 16
      dynamic.go
  4. 247
      handler.go

63
certificate.go

@ -0,0 +1,63 @@
package main
import (
"crypto/sha256"
"crypto/x509"
"encoding/hex"
"net"
"net/url"
"regexp"
"time"
)
func enforceCertificateValidity(clientCerts []*x509.Certificate, conn net.Conn, log *LogEntry) {
// This will fail if any of multiple certs are invalid
// Maybe we should just require one valid?
now := time.Now()
for _, cert := range clientCerts {
if now.Before(cert.NotBefore) {
conn.Write([]byte("64 Client certificate not yet valid!\r\n"))
log.Status = 64
return
} else if now.After(cert.NotAfter) {
conn.Write([]byte("65 Client certificate has expired!\r\n"))
log.Status = 65
return
}
}
}
func handleCertificateZones(URL *url.URL, clientCerts []*x509.Certificate, config Config, conn net.Conn, log *LogEntry) {
authorised := true
for zone, allowedFingerprints := range config.CertificateZones {
matched, err := regexp.Match(zone, []byte(URL.Path))
if !matched || err != nil {
continue
}
authorised = false
for _, clientCert := range clientCerts {
for _, allowedFingerprint := range allowedFingerprints {
if getCertFingerprint(clientCert) == allowedFingerprint {
authorised = true
break
}
}
}
}
if !authorised {
if len(clientCerts) > 0 {
conn.Write([]byte("61 Provided certificate not authorised for this resource\r\n"))
log.Status = 61
} else {
conn.Write([]byte("60 A pre-authorised certificate is required to access this resource\r\n"))
log.Status = 60
}
return
}
}
func getCertFingerprint(cert *x509.Certificate) string {
hash := sha256.Sum256(cert.Raw)
fingerprint := hex.EncodeToString(hash[:])
return fingerprint
}

115
dirlist.go

@ -0,0 +1,115 @@
package main
import (
"bufio"
"fmt"
"io/ioutil"
"log"
"net/url"
"os"
"path/filepath"
"sort"
"strings"
)
func generateDirectoryListing(URL *url.URL, path string, config Config) string {
var listing string
files, err := ioutil.ReadDir(path)
if err != nil {
log.Fatal(err)
}
listing = "# Directory listing\n\n"
// Override with .mollyhead file
header_path := filepath.Join(path, ".mollyhead")
_, err = os.Stat(header_path)
if err == nil {
header, err := ioutil.ReadFile(header_path)
if err == nil {
listing = string(header)
}
}
// Do "up" link first
if URL.Path != "/" {
if strings.HasSuffix(URL.Path, "/") {
URL.Path = URL.Path[:len(URL.Path)-1]
}
up := filepath.Dir(URL.Path)
listing += fmt.Sprintf("=> %s %s\n", up, "..")
}
// Sort files
sort.SliceStable(files, func(i, j int) bool {
if config.DirectoryReverse {
i, j = j, i
}
if config.DirectorySort == "Name" {
return files[i].Name() < files[j].Name()
} else if config.DirectorySort == "Size" {
return files[i].Size() < files[j].Size()
} else if config.DirectorySort == "Time" {
return files[i].ModTime().Before(files[j].ModTime())
}
return false // Should not happen
})
// Format lines
for _, file := range files {
// Skip dotfiles
if strings.HasPrefix(file.Name(), ".") {
continue
}
// Only list world readable files
if uint64(file.Mode().Perm())&0444 != 0444 {
continue
}
listing += fmt.Sprintf("=> %s %s\n", url.PathEscape(file.Name()), generatePrettyFileLabel(file, path, config))
}
return listing
}
func generatePrettyFileLabel(info os.FileInfo, path string, config Config) string {
var size string
if info.IsDir() {
size = " "
} else if info.Size() < 1024 {
size = fmt.Sprintf("%4d B", info.Size())
} else if info.Size() < (1024 << 10) {
size = fmt.Sprintf("%4d KiB", info.Size()>>10)
} else if info.Size() < 1024<<20 {
size = fmt.Sprintf("%4d MiB", info.Size()>>20)
} else if info.Size() < 1024<<30 {
size = fmt.Sprintf("%4d GiB", info.Size()>>30)
} else if info.Size() < 1024<<40 {
size = fmt.Sprintf("%4d TiB", info.Size()>>40)
} else {
size = "GIGANTIC"
}
name := info.Name()
if config.DirectoryTitles && filepath.Ext(name) == "."+config.GeminiExt {
name = readHeading(path, info)
}
if len(name) > 40 {
name = info.Name()[:36] + "..."
}
if info.IsDir() {
name += "/"
}
return fmt.Sprintf("%-40s %s %v", name, size, info.ModTime().Format("Jan _2 2006"))
}
func readHeading(path string, info os.FileInfo) string {
filePath := filepath.Join(path, info.Name())
file, err := os.Open(filePath)
if err != nil {
return info.Name()
}
defer file.Close()
scanner := bufio.NewScanner(file)
for scanner.Scan() {
line := scanner.Text()
if strings.HasPrefix(line, "# ") {
return strings.TrimSpace(line[1:])
}
}
return info.Name()
}

16
dynamic.go

@ -3,13 +3,11 @@ package main
import (
"bufio"
"context"
"crypto/sha256"
"crypto/tls"
"crypto/x509"
"encoding/hex"
"io"
"net"
"net/url"
"os"
"os/exec"
"strconv"
"strings"
@ -17,6 +15,12 @@ import (
)
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)
@ -156,9 +160,3 @@ func prepareGatewayVariables(config Config, URL *url.URL, conn net.Conn) map[str
}
return vars
}
func getCertFingerprint(cert *x509.Certificate) string {
hash := sha256.Sum256(cert.Raw)
fingerprint := hex.EncodeToString(hash[:])
return fingerprint
}

247
handler.go

@ -7,14 +7,12 @@ import (
"fmt"
"github.com/BurntSushi/toml"
"io/ioutil"
"log"
"mime"
"net"
"net/url"
"os"
"path/filepath"
"regexp"
"sort"
"strconv"
"strings"
"time"
@ -36,21 +34,11 @@ func handleGeminiRequest(conn net.Conn, config Config, accessLogEntries chan Log
return
}
// Enforce client certificate validity
clientCerts := tlsConn.ConnectionState().PeerCertificates
// Check validity
// This will fail if any of multiple certs are invalid
// Maybe we should just require one valid?
now := time.Now()
for _, cert := range clientCerts {
if now.Before(cert.NotBefore) {
conn.Write([]byte("64 Client certificate not yet valid!\r\n"))
log.Status = 64
return
} else if now.After(cert.NotAfter) {
conn.Write([]byte("65 Client certificate has expired!\r\n"))
log.Status = 65
return
}
enforceCertificateValidity(clientCerts, conn, &log)
if log.Status != 0 {
return
}
// Reject non-gemini schemes
@ -77,69 +65,39 @@ func handleGeminiRequest(conn net.Conn, config Config, accessLogEntries chan Log
// Resolve URI path to actual filesystem path
path := resolvePath(URL.Path, config)
// Paranoid security measures:
// Fail ASAP if the URL has mapped to a sensitive file
if path == config.CertPath || path == config.KeyPath || path == config.AccessLog || path == config.ErrorLog {
conn.Write([]byte("51 Not found!\r\n"))
log.Status = 51
return
}
// Read Molly files
if config.ReadMollyFiles {
parseMollyFiles(path, &config, errorLogEntries)
}
// Check for redirects
for src, dst := range config.TempRedirects {
if URL.Path == src {
URL.Path = dst
conn.Write([]byte("30 " + URL.String() + "\r\n"))
log.Status = 30
return
}
}
for src, dst := range config.PermRedirects {
if URL.Path == src {
URL.Path = dst
conn.Write([]byte("31 " + URL.String() + "\r\n"))
log.Status = 31
return
}
handleRedirects(URL, config, conn, &log)
if log.Status != 0 {
return
}
// Check whether this URL is in a certificate zone
authorised := true
for zone, allowedFingerprints := range config.CertificateZones {
matched, err := regexp.Match(zone, []byte(URL.Path))
if !matched || err != nil {
continue
}
authorised = false
for _, clientCert := range clientCerts {
for _, allowedFingerprint := range allowedFingerprints {
if getCertFingerprint(clientCert) == allowedFingerprint {
authorised = true
break
}
}
}
}
if !authorised {
if len(clientCerts) > 0 {
conn.Write([]byte("61 Provided certificate not authorised for this resource\r\n"))
log.Status = 61
} else {
conn.Write([]byte("60 A pre-authorised certificate is required to access this resource\r\n"))
log.Status = 60
}
handleCertificateZones(URL, clientCerts, config, conn, &log)
if log.Status != 0 {
return
}
// Check whether this URL is in a configured CGI path
for _, cgiPath := range config.CGIPaths {
inCGIPath, err := regexp.Match(cgiPath, []byte(path))
if err != nil || !inCGIPath {
continue
}
info, err := os.Stat(path)
if err != nil {
continue
}
if info.Mode().Perm()&0111 == 0111 {
if err == nil && inCGIPath {
handleCGI(config, path, URL, &log, errorLogEntries, conn)
return
if log.Status != 0 {
return
}
}
}
@ -168,48 +126,19 @@ func handleGeminiRequest(conn net.Conn, config Config, accessLogEntries chan Log
return
}
// Paranoid security measure:
// Fail if the URL has mapped to our TLS files or the log
if path == config.CertPath || path == config.KeyPath || path == config.AccessLog || path == config.ErrorLog {
conn.Write([]byte("51 Not found!\r\n"))
log.Status = 51
return
}
// Don't serve Molly files
if !info.IsDir() && filepath.Base(path) == ".molly" {
if filepath.Base(path) == ".molly" {
conn.Write([]byte("51 Not found!\r\n"))
log.Status = 51
return
}
// Handle directories
// Finally, serve the file or directory
if info.IsDir() {
// Redirect to add trailing slash if missing
// (otherwise relative links don't work properly)
if !strings.HasSuffix(URL.Path, "/") {
conn.Write([]byte(fmt.Sprintf("31 %s\r\n", URL.String()+"/")))
log.Status = 31
return
}
// Check for index.gmi if path is a directory
index_path := filepath.Join(path, "index."+config.GeminiExt)
index_info, err := os.Stat(index_path)
if err == nil && uint64(index_info.Mode().Perm())&0444 == 0444 {
serveFile(index_path, &log, conn, config, errorLogEntries)
// Serve a generated listing
} else {
conn.Write([]byte("20 text/gemini\r\n"))
log.Status = 20
conn.Write([]byte(generateDirectoryListing(URL, path, config)))
}
return
serveDirectory(URL, path, &log, conn, config, errorLogEntries)
} else {
serveFile(path, &log, conn, config, errorLogEntries)
}
// Otherwise, serve the file contents
serveFile(path, &log, conn, config, errorLogEntries)
return
}
func readRequest(conn net.Conn, log *LogEntry, errorLog chan string) (*url.URL, error) {
@ -318,106 +247,44 @@ func parseMollyFiles(path string, config *Config, errorLogEntries chan string) {
}
}
func generateDirectoryListing(URL *url.URL, path string, config Config) string {
var listing string
files, err := ioutil.ReadDir(path)
if err != nil {
log.Fatal(err)
}
listing = "# Directory listing\n\n"
// Override with .mollyhead file
header_path := filepath.Join(path, ".mollyhead")
_, err = os.Stat(header_path)
if err == nil {
header, err := ioutil.ReadFile(header_path)
if err == nil {
listing = string(header)
}
}
// Do "up" link first
if URL.Path != "/" {
if strings.HasSuffix(URL.Path, "/") {
URL.Path = URL.Path[:len(URL.Path)-1]
func handleRedirects(URL *url.URL, config Config, conn net.Conn, log *LogEntry) {
for src, dst := range config.TempRedirects {
if URL.Path == src {
URL.Path = dst
conn.Write([]byte("30 " + URL.String() + "\r\n"))
log.Status = 30
return
}
up := filepath.Dir(URL.Path)
listing += fmt.Sprintf("=> %s %s\n", up, "..")
}
// Sort files
sort.SliceStable(files, func(i, j int) bool {
if config.DirectoryReverse {
i, j = j, i
}
if config.DirectorySort == "Name" {
return files[i].Name() < files[j].Name()
} else if config.DirectorySort == "Size" {
return files[i].Size() < files[j].Size()
} else if config.DirectorySort == "Time" {
return files[i].ModTime().Before(files[j].ModTime())
}
return false // Should not happen
})
// Format lines
for _, file := range files {
// Skip dotfiles
if strings.HasPrefix(file.Name(), ".") {
continue
}
// Only list world readable files
if uint64(file.Mode().Perm())&0444 != 0444 {
continue
for src, dst := range config.PermRedirects {
if URL.Path == src {
URL.Path = dst
conn.Write([]byte("31 " + URL.String() + "\r\n"))
log.Status = 31
return
}
listing += fmt.Sprintf("=> %s %s\n", url.PathEscape(file.Name()), generatePrettyFileLabel(file, path, config))
}
return listing
}
func generatePrettyFileLabel(info os.FileInfo, path string, config Config) string {
var size string
if info.IsDir() {
size = " "
} else if info.Size() < 1024 {
size = fmt.Sprintf("%4d B", info.Size())
} else if info.Size() < (1024 << 10) {
size = fmt.Sprintf("%4d KiB", info.Size()>>10)
} else if info.Size() < 1024<<20 {
size = fmt.Sprintf("%4d MiB", info.Size()>>20)
} else if info.Size() < 1024<<30 {
size = fmt.Sprintf("%4d GiB", info.Size()>>30)
} else if info.Size() < 1024<<40 {
size = fmt.Sprintf("%4d TiB", info.Size()>>40)
} else {
size = "GIGANTIC"
}
name := info.Name()
if config.DirectoryTitles && filepath.Ext(name) == "."+config.GeminiExt {
name = readHeading(path, info)
}
if len(name) > 40 {
name = info.Name()[:36] + "..."
}
if info.IsDir() {
name += "/"
}
return fmt.Sprintf("%-40s %s %v", name, size, info.ModTime().Format("Jan _2 2006"))
}
func readHeading(path string, info os.FileInfo) string {
filePath := filepath.Join(path, info.Name())
file, err := os.Open(filePath)
if err != nil {
return info.Name()
func serveDirectory(URL *url.URL, path string, log *LogEntry, conn net.Conn, config Config, errorLogEntries chan string) {
// Redirect to add trailing slash if missing
// (otherwise relative links don't work properly)
if !strings.HasSuffix(URL.Path, "/") {
conn.Write([]byte(fmt.Sprintf("31 %s\r\n", URL.String()+"/")))
log.Status = 31
return
}
defer file.Close()
scanner := bufio.NewScanner(file)
for scanner.Scan() {
line := scanner.Text()
if strings.HasPrefix(line, "# ") {
return strings.TrimSpace(line[1:])
}
// Check for index.gmi if path is a directory
index_path := filepath.Join(path, "index."+config.GeminiExt)
index_info, err := os.Stat(index_path)
if err == nil && uint64(index_info.Mode().Perm())&0444 == 0444 {
serveFile(index_path, log, conn, config, errorLogEntries)
// Serve a generated listing
} else {
conn.Write([]byte("20 text/gemini\r\n"))
log.Status = 20
conn.Write([]byte(generateDirectoryListing(URL, path, config)))
}
return info.Name()
}
func serveFile(path string, log *LogEntry, conn net.Conn, config Config, errorLog chan string) {

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