Calling Read before Write ignores the fingerprint #75
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What's wrong with calling Handshake?
This is an unusual use-case with client connecting, and waiting for server
to send data.
…On Thu, Apr 1, 2021, 01:56 Hirbod Behnam ***@***.***> wrote:
Hello
If you call Read before Handshake or Write, the default go ciphers will
be used. This is because the Write method is implemented for UConn and
the handshake in it will call the utls handshake. But the Read method is
implemented by Conn and executing it will cause the Read to call the tls
handshake instead of utls one.
Is this intended? And if so, is there anyway (except Handshake) to
establish the connection with fingerprints by calling Read at first?
Thanks
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Hello |
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We met the same problem while we tried to integrate utls into golang net/http package. |
I was just bitten by this problem as well, in the same situation: a pair of read/write goroutines started immediately after calling Calling
Here is a running example of the network communication pattern I was using. I do not think it is anything too unusual. You can run, for example, demo.go// Demo for https://github.com/refraction-networking/utls/issues/75
// go run demo.go -- example.com:443
package main
import (
"flag"
"fmt"
"io"
"net"
"os"
"sync"
"github.com/refraction-networking/utls"
)
func utlsDial(network, addr string, config *tls.Config) (*tls.UConn, error) {
conn, err := net.Dial(network, addr)
if err != nil {
return nil, err
}
uconn := tls.UClient(conn, config, tls.HelloChrome_83)
// err = uconn.Handshake()
// if err != nil {
// uconn.Close()
// return nil, err
// }
return uconn, nil
}
func demo(addr string) error {
serverName, _, err := net.SplitHostPort(addr)
if err != nil {
return err
}
tlsConfig := tls.Config{ServerName: serverName}
uconn, err := utlsDial("tcp", addr, &tlsConfig)
if err != nil {
return err
}
defer uconn.Close()
var wg sync.WaitGroup
wg.Add(2)
go func() {
defer wg.Done()
_, err := io.Copy(os.Stdout, uconn)
if err != nil {
fmt.Fprintf(os.Stderr, "stdout←uconn: %v\n", err)
}
}()
go func() {
defer wg.Done()
_, err := io.Copy(uconn, os.Stdin)
if err != nil {
fmt.Fprintf(os.Stderr, "uconn←stdin: %v\n", err)
}
}()
wg.Wait()
return nil
}
func main() {
flag.Parse()
if flag.NArg() != 1 {
fmt.Fprintf(os.Stderr, "%s: need a target host:port\n", os.Args[0])
os.Exit(1)
}
err := demo(flag.Arg(0))
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
}
Wireshark dissection of ClientHelloTransport Layer Security
TLSv1.3 Record Layer: Handshake Protocol: Client Hello
Content Type: Handshake (22)
Version: TLS 1.0 (0x0301)
Length: 255
Handshake Protocol: Client Hello
Handshake Type: Client Hello (1)
Length: 251
Version: TLS 1.2 (0x0303)
Random: RANDOM
Session ID Length: 32
Session ID: ID
Cipher Suites Length: 38
Cipher Suites (19 suites)
Cipher Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (0xc02f)
Cipher Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (0xc030)
Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (0xc02b)
Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (0xc02c)
Cipher Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 (0xcca8)
Cipher Suite: TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 (0xcca9)
Cipher Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (0xc013)
Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA (0xc009)
Cipher Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (0xc014)
Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (0xc00a)
Cipher Suite: TLS_RSA_WITH_AES_128_GCM_SHA256 (0x009c)
Cipher Suite: TLS_RSA_WITH_AES_256_GCM_SHA384 (0x009d)
Cipher Suite: TLS_RSA_WITH_AES_128_CBC_SHA (0x002f)
Cipher Suite: TLS_RSA_WITH_AES_256_CBC_SHA (0x0035)
Cipher Suite: TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA (0xc012)
Cipher Suite: TLS_RSA_WITH_3DES_EDE_CBC_SHA (0x000a)
Cipher Suite: TLS_AES_128_GCM_SHA256 (0x1301)
Cipher Suite: TLS_CHACHA20_POLY1305_SHA256 (0x1303)
Cipher Suite: TLS_AES_256_GCM_SHA384 (0x1302)
Compression Methods Length: 1
Compression Methods (1 method)
Compression Method: null (0)
Extensions Length: 140
Extension: server_name (len=15)
Type: server_name (0)
Length: 15
Server Name Indication extension
Server Name list length: 13
Server Name Type: host_name (0)
Server Name length: 10
Server Name: dns.google
Extension: status_request (len=5)
Type: status_request (5)
Length: 5
Certificate Status Type: OCSP (1)
Responder ID list Length: 0
Request Extensions Length: 0
Extension: supported_groups (len=10)
Type: supported_groups (10)
Length: 10
Supported Groups List Length: 8
Supported Groups (4 groups)
Supported Group: x25519 (0x001d)
Supported Group: secp256r1 (0x0017)
Supported Group: secp384r1 (0x0018)
Supported Group: secp521r1 (0x0019)
Extension: ec_point_formats (len=2)
Type: ec_point_formats (11)
Length: 2
EC point formats Length: 1
Elliptic curves point formats (1)
EC point format: uncompressed (0)
Extension: signature_algorithms (len=24)
Type: signature_algorithms (13)
Length: 24
Signature Hash Algorithms Length: 22
Signature Hash Algorithms (11 algorithms)
Signature Algorithm: rsa_pss_rsae_sha256 (0x0804)
Signature Hash Algorithm Hash: Unknown (8)
Signature Hash Algorithm Signature: Unknown (4)
Signature Algorithm: rsa_pss_rsae_sha384 (0x0805)
Signature Hash Algorithm Hash: Unknown (8)
Signature Hash Algorithm Signature: Unknown (5)
Signature Algorithm: rsa_pss_rsae_sha512 (0x0806)
Signature Hash Algorithm Hash: Unknown (8)
Signature Hash Algorithm Signature: Unknown (6)
Signature Algorithm: rsa_pkcs1_sha256 (0x0401)
Signature Hash Algorithm Hash: SHA256 (4)
Signature Hash Algorithm Signature: RSA (1)
Signature Algorithm: ecdsa_secp256r1_sha256 (0x0403)
Signature Hash Algorithm Hash: SHA256 (4)
Signature Hash Algorithm Signature: ECDSA (3)
Signature Algorithm: rsa_pkcs1_sha384 (0x0501)
Signature Hash Algorithm Hash: SHA384 (5)
Signature Hash Algorithm Signature: RSA (1)
Signature Algorithm: ecdsa_secp384r1_sha384 (0x0503)
Signature Hash Algorithm Hash: SHA384 (5)
Signature Hash Algorithm Signature: ECDSA (3)
Signature Algorithm: rsa_pkcs1_sha512 (0x0601)
Signature Hash Algorithm Hash: SHA512 (6)
Signature Hash Algorithm Signature: RSA (1)
Signature Algorithm: ecdsa_secp521r1_sha512 (0x0603)
Signature Hash Algorithm Hash: SHA512 (6)
Signature Hash Algorithm Signature: ECDSA (3)
Signature Algorithm: rsa_pkcs1_sha1 (0x0201)
Signature Hash Algorithm Hash: SHA1 (2)
Signature Hash Algorithm Signature: RSA (1)
Signature Algorithm: ecdsa_sha1 (0x0203)
Signature Hash Algorithm Hash: SHA1 (2)
Signature Hash Algorithm Signature: ECDSA (3)
Extension: renegotiation_info (len=1)
Type: renegotiation_info (65281)
Length: 1
Renegotiation Info extension
Renegotiation info extension length: 0
Extension: signed_certificate_timestamp (len=0)
Type: signed_certificate_timestamp (18)
Length: 0
Extension: supported_versions (len=9)
Type: supported_versions (43)
Length: 9
Supported Versions length: 8
Supported Version: TLS 1.3 (0x0304)
Supported Version: TLS 1.2 (0x0303)
Supported Version: TLS 1.1 (0x0302)
Supported Version: TLS 1.0 (0x0301)
Extension: key_share (len=38)
Type: key_share (51)
Length: 38
Key Share extension
Client Key Share Length: 36
Key Share Entry: Group: x25519, Key Exchange length: 32
Group: x25519 (29)
Key Exchange Length: 32
Key Exchange: EXCHANGE
Wireshark dissection of ClientHello, when
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gaukas
added
bug
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I know this fix is kinda late, but let's hope in the future such thing can be patched in a timely manner. |
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#292 is merged, and I think we can close this issue for now. Are we good? |
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Hello
If you call
ReadbeforeHandshakeorWrite, the default go ciphers will be used. This is because theWritemethod is implemented forUConnand the handshake in it will call the utls handshake. But theReadmethod is implemented byConnand executing it will cause theReadto call the tls handshake instead of utls one.Is this intended? And if so, is there anyway (except Handshake) to establish the connection with fingerprints by calling
Readat first?Thanks
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