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12 Commits

Author SHA1 Message Date
AJ ONeal 8ba42a09a4 silence more output, fix minor output bugs 2021-06-21 23:22:34 -06:00
AJ ONeal 66f2d41c6b -q => -s (to be curl-like), make staticcheck happy 2021-06-21 23:05:27 -06:00
Kevin Chung ca84ed48de Add -quiet and -q flags 2021-06-17 15:27:21 -04:00
AJ ONeal 455db50928 ignore builds 2020-12-02 15:05:10 -07:00
AJ ONeal 5b0374f2e9 add version 2020-12-02 15:04:58 -07:00
AJ ONeal af639f0b2e update build / install instructions 2020-12-02 14:23:07 -07:00
AJ ONeal 828344802b add .goreleaser.yml 2020-12-02 14:05:25 -07:00
AJ ONeal 5334a377a4 doc updates 2019-05-21 19:25:06 -06:00
AJ ONeal 959268bf31 doc updates 2019-05-21 19:15:43 -06:00
AJ ONeal 79c2ac5f3d update to be more go-ish 2019-05-21 18:54:02 -06:00
AJ ONeal 1e9f579043 use go1.11 modules 2019-01-07 22:27:10 -07:00
AJ ONeal 8042bcf41c update -servername => --servername 2018-09-03 16:05:50 -06:00
9 changed files with 284 additions and 162 deletions

3
.gitignore vendored
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@ -1 +1,4 @@
/sclient
/cmd/sclient/sclient
dist

37
.goreleaser.yml Normal file
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@ -0,0 +1,37 @@
before:
hooks:
- go mod download
- go generate ./...
builds:
- main: ./cmd/sclient/main.go
env:
- CGO_ENABLED=0
goos:
- linux
- windows
- darwin
goarch:
- 386
- amd64
- arm
- arm64
goarm:
- 6
- 7
archives:
- replacements:
386: i386
amd64: x86_64
format_overrides:
- goos: windows
format: zip
checksum:
name_template: 'checksums.txt'
snapshot:
name_template: "{{ .Tag }}-next"
changelog:
sort: asc
filters:
exclude:
- '^docs:'
- '^test:'

114
README.md
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@ -1,5 +1,4 @@
sclient.go
==========
# sclient
Secure Client for exposing TLS (aka SSL) secured services as plain-text connections locally.
@ -8,77 +7,75 @@ Also ideal for multiplexing a single port with multiple protocols using SNI.
Unwrap a TLS connection:
```bash
$ sclient whatever.com:443 localhost:3000
sclient whatever.com:443 localhost:3000
> [listening] whatever.com:443 <= localhost:3000
```
Connect via Telnet
```bash
$ telnet localhost 3000
telnet localhost 3000
```
Connect via netcat (nc)
```bash
$ nc localhost 3000
nc localhost 3000
```
cURL
```bash
$ curl http://localhost:3000 -H 'Host: whatever.com'
curl http://localhost:3000 -H 'Host: whatever.com'
```
A poor man's (or Windows user's) makeshift replacement for `openssl s_client`, `stunnel`, or `socat`.
Install
=======
# Table of Contents
- [Install](#install)
- [Usage](#usage)
- [Examples](#examples)
- [Build from Source](#build-from-source)
# Install
### Mac, Linux
```bash
curl -sS https://webinstall.dev/sclient | bash
```
```bash
curl.exe -A MS https://webinstall.dev/sclient | powershell
```
### Downloads
* [Windows 10](https://telebit.cloud/sclient/dist/windows/amd64/sclient.exe)
* [Mac OS X](https://telebit.cloud/sclient/dist/darwin/amd64/sclient)
* [Linux (x64)](https://telebit.cloud/sclient/dist/linux/amd64/sclient)
* [Raspberry Pi (armv7)](https://telebit.cloud/sclient/dist/linux/armv7/sclient)
* more downloads <https://telebit.cloud/sclient/>
Check the [Github Releases](https://github.com/therootcompany/sclient/releases) for
### Build from source
- macOS (x64) Apple Silicon [coming soon](https://github.com/golang/go/issues/39782)
- Linux (x64, i386, arm64, arm6, arm7)
- Windows 10 (x64, i386)
For the moment you'll have to install go and compile `sclient` yourself:
* <https://golang.org/doc/install#install>
```bash
git clone https://git.coolaj86.com/coolaj86/sclient.go.git
pushd sclient.go
go build -o dist/sclient cmd/sclient/main.go
rsync -av dist/sclient /usr/local/bin/sclient
```
```bash
go run cmd/sclient/main.go example.com:443 localhost:3000
```
Usage
=====
# Usage
```bash
sclient [flags] <remote> <local>
```
* flags
* -k, --insecure ignore invalid TLS (SSL/HTTPS) certificates
* --servername <string> spoof SNI (to disable use IP as &lt;remote&gt; and do not use this option)
* remote
* must have servername (i.e. example.com)
* port is optional (default is 443)
* local
* address is optional (default is localhost)
* must have port (i.e. 3000)
- flags
- -k, --insecure ignore invalid TLS (SSL/HTTPS) certificates
- --servername <string> spoof SNI (to disable use IP as &lt;remote&gt; and do not use this option)
- remote
- must have servername (i.e. example.com)
- port is optional (default is 443)
- local
- address is optional (default is localhost)
- must have port (i.e. 3000)
Examples
========
# Examples
Bridge between `telebit.cloud` and local port `3000`.
@ -117,9 +114,38 @@ printf "GET / HTTP/1.1\r\nHost: telebit.cloud\r\n\r\n" | sclient telebit.cloud:4
Testing for security vulnerabilities on the remote:
```bash
sclient -servername "Robert'); DROP TABLE Students;" example.com localhost:3000
sclient --servername "Robert'); DROP TABLE Students;" -k example.com localhost:3000
```
```bash
sclient -servername "../../../.hidden/private.txt" example.com localhost:3000
sclient --servername "../../../.hidden/private.txt" -k example.com localhost:3000
```
# Build from source
You'll need to install [Go](https://golang.org).
See [webinstall.dev/golang](https://webinstall.dev/golang) for install instructions.
```bash
curl -sS https://webinstall.dev/golang | bash
```
Then you can install and run as per usual.
```bash
git clone https://git.rootprojects.org/root/sclient.go.git
pushd sclient.go
go build -o dist/sclient cmd/sclient/main.go
sudo rsync -av dist/sclient /usr/local/bin/sclient
popd
sclient example.com:443 localhost:3000
```
## Install or Run with Go
```bash
go get git.rootprojects.org/root/sclient.go/cmd/sclient
go run git.rootprojects.org/root/sclient.go/cmd/sclient example.com:443 localhost:3000
```

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@ -1,33 +0,0 @@
#GOOS=windows GOARCH=amd64 go install
go tool dist list
gocmd=cmd/sclient/main.go
golib=""
echo ""
echo ""
echo "Windows amd64"
GOOS=windows GOARCH=amd64 go build -o dist/windows/amd64/sclient.exe $gocmd $golib
echo "Windows 386"
GOOS=windows GOARCH=386 go build -o dist/windows/386/sclient.exe $gocmd $golib
echo ""
echo "Darwin (macOS) amd64"
GOOS=darwin GOARCH=amd64 go build -o dist/darwin/amd64/sclient $gocmd $golib
echo ""
echo "Linux amd64"
GOOS=linux GOARCH=amd64 go build -o dist/linux/amd64/sclient $gocmd $golib
echo "Linux 386"
echo ""
GOOS=linux GOARCH=386 go build -o dist/linux/386/sclient $gocmd $golib
echo "RPi 3 B+ ARMv7"
GOOS=linux GOARCH=arm GOARM=7 go build -o dist/linux/armv7/sclient $gocmd $golib
echo "RPi Zero ARMv5"
GOOS=linux GOARCH=arm GOARM=5 go build -o dist/linux/armv5/sclient $gocmd $golib
echo ""
echo ""
rsync -av ./dist/ root@telebit.cloud:/opt/telebit-relay/lib/extensions/admin/sclient/dist/

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@ -7,26 +7,52 @@ import (
"strconv"
"strings"
sclient "git.coolaj86.com/sclient.go"
sclient "git.rootprojects.org/root/sclient.go"
)
var (
// commit refers to the abbreviated commit hash
commit = "0000000"
// version refers to the most recent tag, plus any commits made since then
version = "v0.0.0-pre0+0000000"
// GitTimestamp refers to the timestamp of the most recent commit
date = "0000-00-00T00:00:00+0000"
)
func ver() string {
return fmt.Sprintf("sclient %s (%s) %s", version, commit[:7], date)
}
func usage() {
fmt.Fprintf(os.Stderr, "\nusage: sclient <remote> <local>\n"+
fmt.Fprintf(os.Stderr, "\n%s\n"+
"\nusage: sclient <remote> <local>\n"+
"\n"+
" ex: sclient example.com 3000\n"+
" (sclient example.com:443 localhost:3000)\n"+
"\n"+
" ex: sclient example.com:8443 0.0.0.0:4080\n"+
"\n")
"\n"+
" ex: sclient example.com:443 -\n"+
"\n", ver())
flag.PrintDefaults()
fmt.Println()
}
func main() {
if len(os.Args) >= 2 {
if "version" == strings.TrimLeft(os.Args[1], "-") {
fmt.Printf("%s\n", ver())
os.Exit(0)
return
}
}
flag.Usage = usage
insecure := flag.Bool("k", false, "ignore bad TLS/SSL/HTTPS certificates")
insecure := flag.Bool("k", false, "alias for --insecure")
silent := flag.Bool("s", false, "alias of --silent")
servername := flag.String("servername", "", "specify a servername different from <remote> (to disable SNI use an IP as <remote> and do use this option)")
flag.BoolVar(insecure, "insecure", false, "ignore bad TLS/SSL/HTTPS certificates")
flag.BoolVar(silent, "silent", false, "less verbose output")
flag.Parse()
remotestr := flag.Arg(0)
localstr := flag.Arg(1)
@ -42,11 +68,12 @@ func main() {
}
}
opts := &sclient.PipeOpts{
sclient := &sclient.Tunnel{
RemotePort: 443,
LocalAddress: "localhost",
InsecureSkipVerify: *insecure,
ServerName: *servername,
Silent: *silent,
}
remote := strings.Split(remotestr, ":")
@ -57,17 +84,17 @@ func main() {
usage()
os.Exit(0)
}
opts.RemotePort = rport
sclient.RemotePort = rport
} else if 1 != len(remote) {
usage()
os.Exit(0)
}
opts.RemoteAddress = remote[0]
sclient.RemoteAddress = remote[0]
if "-" == localstr || "|" == localstr {
// User may specify stdin/stdout instead of net
opts.LocalAddress = localstr
opts.LocalPort = -1
sclient.LocalAddress = localstr
sclient.LocalPort = -1
} else {
// Test that argument is a local address
local := strings.Split(localstr, ":")
@ -78,20 +105,19 @@ func main() {
usage()
os.Exit(0)
}
opts.LocalPort = lport
sclient.LocalPort = lport
} else {
lport, err := strconv.Atoi(local[1])
if nil != err {
usage()
os.Exit(0)
}
opts.LocalAddress = local[0]
opts.LocalPort = lport
sclient.LocalAddress = local[0]
sclient.LocalPort = lport
}
}
sclient := &sclient.Tun{}
err := sclient.DialAndListen(opts)
err := sclient.DialAndListen()
if nil != err {
fmt.Fprintf(os.Stderr, "%s\n", err)
//usage()

43
doc.go Normal file
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@ -0,0 +1,43 @@
/*
sclient unwraps SSL.
It makes secure remote connections (such as HTTPS) available locally as plain-text connections -
similar to `stunnel` or `openssl s_client`.
There are a variety of reasons that you might want to do that,
but we created it specifically to be able to upgrade applications with legacy
security protocols - like SSH, OpenVPN, and Postgres - to take
advantage of the features of modern TLS, such as ALPN and SNI
(which makes them routable through almost every type of firewall).
See https://telebit.cloud/sclient for more info.
Package Basics
In the simplest case you'll just be setting a ServerName and connection info:
servername := "example.com"
sclient := &sclient.Tunnel{
ServerName: servername,
RemoteAddress: servername,
RemotePort: 443,
LocalAddress: "localhost",
LocalPort: 3000,
}
err := sclient.DialAndListen()
Try the CLI
If you'd like to better understand what sclient does, you can try it out with `go run`:
go get git.rootprojects.org/root/sclient.go/cmd/sclient
go run git.rootprojects.org/root/sclient.go/cmd/sclient example.com:443 localhost:3000
curl http://localhost:3000 -H "Host: example.com"
Pre-built versions for various platforms are also available at
https://telebit.cloud/sclient
*/
package sclient

3
go.mod Normal file
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@ -0,0 +1,3 @@
module git.rootprojects.org/root/sclient.go
go 1.12

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@ -10,6 +10,69 @@ import (
"strings"
)
// Tunnel specifies which remote encrypted connection to make available as a plain connection locally.
type Tunnel struct {
RemoteAddress string
RemotePort int
LocalAddress string
LocalPort int
InsecureSkipVerify bool
ServerName string
Silent bool
}
// DialAndListen will create a test TLS connection to the remote address and then
// begin listening locally. Each local connection will result in a separate remote connection.
func (t *Tunnel) DialAndListen() error {
remote := t.RemoteAddress + ":" + strconv.Itoa(t.RemotePort)
conn, err := tls.Dial("tcp", remote,
&tls.Config{
ServerName: t.ServerName,
InsecureSkipVerify: t.InsecureSkipVerify,
})
if err != nil {
fmt.Fprintf(os.Stderr, "[warn] '%s' may not be accepting connections: %s\n", remote, err)
} else {
conn.Close()
}
// use stdin/stdout
if "-" == t.LocalAddress || "|" == t.LocalAddress {
var name string
network := "stdio"
if "|" == t.LocalAddress {
name = "pipe"
} else {
name = "stdin"
}
conn := &stdnet{os.Stdin, os.Stdout, &stdaddr{net.UnixAddr{Name: name, Net: network}}}
t.handleConnection(remote, conn)
return nil
}
// use net.Conn
local := t.LocalAddress + ":" + strconv.Itoa(t.LocalPort)
ln, err := net.Listen("tcp", local)
if err != nil {
return err
}
if !t.Silent {
fmt.Fprintf(os.Stdout, "[listening] %s:%d <= %s:%d\n",
t.RemoteAddress, t.RemotePort, t.LocalAddress, t.LocalPort)
}
for {
conn, err := ln.Accept()
if nil != err {
fmt.Fprintf(os.Stderr, "[error] %s\n", err)
continue
}
go t.handleConnection(remote, conn)
}
}
// I wonder if I can get this to exactly mirror UnixAddr without passing it in
type stdaddr struct {
net.UnixAddr
@ -35,23 +98,12 @@ func (rw *stdnet) RemoteAddr() net.Addr {
}
// not all of net.Conn, just RWC and RemoteAddr()
type Rwc interface {
type netReadWriteCloser interface {
io.ReadWriteCloser
RemoteAddr() net.Addr
}
type PipeOpts struct {
RemoteAddress string
RemotePort int
LocalAddress string
LocalPort int
InsecureSkipVerify bool
ServerName string
}
type Tun struct{}
func pipe(r Rwc, w Rwc, t string) {
func pipe(r netReadWriteCloser, w netReadWriteCloser, t string) {
buffer := make([]byte, 2048)
for {
done := false
@ -61,7 +113,7 @@ func pipe(r Rwc, w Rwc, t string) {
if nil != err {
//fmt.Fprintf(os.Stdout, "[debug] (%s:%d) error reading %s\n", t, count, err)
if io.EOF != err {
fmt.Fprintf(os.Stderr, "[read error] (%s:%s) %s\n", t, count, err)
fmt.Fprintf(os.Stderr, "[read error] (%s:%d) %s\n", t, count, err)
}
r.Close()
//w.Close()
@ -87,11 +139,11 @@ func pipe(r Rwc, w Rwc, t string) {
}
}
func handleConnection(remote string, conn Rwc, opts *PipeOpts) {
func (t *Tunnel) handleConnection(remote string, conn netReadWriteCloser) {
sclient, err := tls.Dial("tcp", remote,
&tls.Config{
ServerName: opts.ServerName,
InsecureSkipVerify: opts.InsecureSkipVerify,
ServerName: t.ServerName,
InsecureSkipVerify: t.InsecureSkipVerify,
})
if err != nil {
@ -100,62 +152,16 @@ func handleConnection(remote string, conn Rwc, opts *PipeOpts) {
return
}
if "stdio" == conn.RemoteAddr().Network() {
fmt.Fprintf(os.Stdout, "(connected to %s:%d and reading from %s)\n",
opts.RemoteAddress, opts.RemotePort, conn.RemoteAddr().String())
} else {
fmt.Fprintf(os.Stdout, "[connect] %s => %s:%d\n",
strings.Replace(conn.RemoteAddr().String(), "[::1]:", "localhost:", 1), opts.RemoteAddress, opts.RemotePort)
if !t.Silent {
if "stdio" == conn.RemoteAddr().Network() {
fmt.Fprintf(os.Stdout, "(connected to %s:%d and reading from %s)\n",
t.RemoteAddress, t.RemotePort, conn.RemoteAddr().String())
} else {
fmt.Fprintf(os.Stdout, "[connect] %s => %s:%d\n",
strings.Replace(conn.RemoteAddr().String(), "[::1]:", "localhost:", 1), t.RemoteAddress, t.RemotePort)
}
}
go pipe(conn, sclient, "local")
pipe(sclient, conn, "remote")
}
func (*Tun) DialAndListen(opts *PipeOpts) error {
remote := opts.RemoteAddress + ":" + strconv.Itoa(opts.RemotePort)
conn, err := tls.Dial("tcp", remote,
&tls.Config{
ServerName: opts.ServerName,
InsecureSkipVerify: opts.InsecureSkipVerify,
})
if err != nil {
fmt.Fprintf(os.Stderr, "[warn] '%s' may not be accepting connections: %s\n", remote, err)
} else {
conn.Close()
}
// use stdin/stdout
if "-" == opts.LocalAddress || "|" == opts.LocalAddress {
var name string
network := "stdio"
if "|" == opts.LocalAddress {
name = "pipe"
} else {
name = "stdin"
}
conn := &stdnet{os.Stdin, os.Stdout, &stdaddr{net.UnixAddr{name, network}}}
handleConnection(remote, conn, opts)
return nil
}
// use net.Conn
local := opts.LocalAddress + ":" + strconv.Itoa(opts.LocalPort)
ln, err := net.Listen("tcp", local)
if err != nil {
return err
}
fmt.Fprintf(os.Stdout, "[listening] %s:%d <= %s:%d\n",
opts.RemoteAddress, opts.RemotePort, opts.LocalAddress, opts.LocalPort)
for {
conn, err := ln.Accept()
if nil != err {
fmt.Fprintf(os.Stderr, "[error] %s\n", err)
continue
}
go handleConnection(remote, conn, opts)
}
}

11
staticcheck.conf Normal file
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@ -0,0 +1,11 @@
# I like my yoda conditions ST1017
checks = ["all", "-ST1017", "-ST1000", "-ST1003", "-ST1016", "-ST1020", "-ST1021", "-ST1022", "-ST1023"]
initialisms = ["ACL", "API", "ASCII", "CPU", "CSS", "DNS",
"EOF", "GUID", "HTML", "HTTP", "HTTPS", "ID",
"IP", "JSON", "QPS", "RAM", "RPC", "SLA",
"SMTP", "SQL", "SSH", "TCP", "TLS", "TTL",
"UDP", "UI", "GID", "UID", "UUID", "URI",
"URL", "UTF8", "VM", "XML", "XMPP", "XSRF",
"XSS", "SIP", "RTP", "AMQP", "DB", "TS"]
dot_import_whitelist = []
http_status_code_whitelist = ["200", "400", "404", "500"]