fix(faketls): fix encoding SNI in faketls ClientHello

The offset calculation used in the stack code in the ClientHello creation function was incorrect, resulting in the SNI field not being correctly encoded and therefore not being able to connect to faketls mtproto proxies. Added parenthesis to fix the math. Signed-off-by: Mark Pashmfouroush <[email protected]>
gotd · Jul 3, 2024 · 736dd57 · 736dd57
1 parent 7183696
commit 736dd57
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Showing 2 changed files with 6 additions and 6 deletions.
diff --git a/mtproxy/faketls/client_hello.go b/mtproxy/faketls/client_hello.go
@@ -44,7 +44,7 @@ func createClientHello(b *bin.Buffer, sessionID [32]byte, domain string, key [32
 		s := stack[lastIdx]
 		stack = stack[:lastIdx]
 
-		length := b.Len() - s + 2
+		length := b.Len() - (s + 2)
 		binary.BigEndian.PutUint16(b.Buf[s:], uint16(length))
 	}
 

diff --git a/mtproxy/faketls/faketls_test.go b/mtproxy/faketls/faketls_test.go
@@ -20,15 +20,15 @@ func TestTLS(t *testing.T) {
 	_, err := writeClientHello(b, c, sessionID, "google.com", secret[:])
 	a.NoError(err)
 
-	testVector := []uint8{
-		0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0xd5, 0x20, 0xce, 0xde, 0x64,
-		0x71, 0x9b, 0xa7, 0x3f, 0x51, 0x9d, 0x51, 0x35, 0xd5, 0x64, 0x31, 0x68, 0x2a, 0xe8, 0x07, 0x98,
-		0xf3, 0xca, 0xb3, 0x32, 0xc4, 0xb2, 0xbc, 0x2e, 0xb5, 0x04, 0x4d, 0x20, 0x00, 0x00, 0x00, 0x00,
+	testVector := []byte{
+		0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0xf9, 0x75, 0x5f, 0xdd, 0xb9,
+		0xe3, 0x46, 0x57, 0x5a, 0x26, 0x71, 0xfa, 0x29, 0x7f, 0xab, 0xf0, 0xa1, 0xf3, 0x69, 0x4f, 0x72,
+		0xe0, 0xc3, 0x8f, 0x62, 0x77, 0x5c, 0x8f, 0x5a, 0xf8, 0xa2, 0xa9, 0x20, 0x00, 0x00, 0x00, 0x00,
 		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x13, 0x01,
 		0x13, 0x02, 0x13, 0x03, 0xc0, 0x2b, 0xc0, 0x2f, 0xc0, 0x2c, 0xc0, 0x30, 0xcc, 0xa9, 0xcc, 0xa8,
 		0xc0, 0x13, 0xc0, 0x14, 0x00, 0x9c, 0x00, 0x9d, 0x00, 0x2f, 0x00, 0x35, 0x01, 0x00, 0x01, 0x93,
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x13, 0x00, 0x11, 0x00, 0x00, 0x0e, 0x67, 0x6f, 0x6f, 0x67, 0x6c,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x0f, 0x00, 0x0d, 0x00, 0x00, 0x0a, 0x67, 0x6f, 0x6f, 0x67, 0x6c,
 		0x65, 0x2e, 0x63, 0x6f, 0x6d, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00, 0x00, 0x0a,
 		0x00, 0x0a, 0x00, 0x08, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x18, 0x00, 0x0b, 0x00, 0x02, 0x01, 0x00,
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