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SaiTLS
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socket: add alert close_notify

This commit is contained in:
occheung 2020-12-03 12:43:31 +08:00
parent 18c307ec1a
commit fe6418df36
2 changed files with 165 additions and 12 deletions
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17
src/session.rs
View File

@ -83,6 +83,8 @@ pub(crate) struct Session<'a> {
// Client must cent Certificate extension iff server requested it
need_send_client_cert: bool,
client_cert_verify_sig_alg: Option<crate::tls_packet::SignatureScheme>,
// Flag for the need of sending alert to terminate TLS session
need_send_alert: Option<AlertType>
}
impl<'a> Session<'a> {
@ -122,7 +124,8 @@ impl<'a> Session<'a> {
cert_public_key: None,
cert_private_key: certificate_with_key,
need_send_client_cert: false,
client_cert_verify_sig_alg: None
client_cert_verify_sig_alg: None,
need_send_alert: None
}
}
@ -150,7 +153,13 @@ impl<'a> Session<'a> {
received_slice: &[u8]
) {
self.hash.update(received_slice);
self.state = TlsState::NEED_RESET(alert);
self.need_send_alert = Some(alert);
}
pub(crate) fn reset_state(&mut self) {
// Clear alert
self.need_send_alert = None;
self.state = TlsState::DEFAULT;
}
// State transition from START to WAIT_SH
@ -1405,6 +1414,10 @@ impl<'a> Session<'a> {
self.remote_endpoint
}
pub(crate) fn get_need_send_alert(&self) -> Option<AlertType> {
self.need_send_alert
}
pub(crate) fn has_completed_handshake(&self) -> bool {
self.state == TlsState::CLIENT_CONNECTED
}

160
src/tls.rs
View File

@ -57,9 +57,7 @@ pub(crate) enum TlsState {
SERVER_WAIT_CERT,
SERVER_WAIT_CV,
SERVER_WAIT_FINISHED,
SERVER_CONNECTED,
// `Derailed` state should any exceptions occur
NEED_RESET(AlertType)
SERVER_CONNECTED
}
pub struct TlsSocket<'a, 'b, 'c>
@ -150,10 +148,20 @@ impl<'a, 'b, 'c> TlsSocket<'a, 'b, 'c> {
self.session.borrow().get_tls_state()
};
let need_send_alert = {
self.session.borrow().get_need_send_alert()
};
// Check TCP socket/ TLS session
{
let tcp_state = self.sockets.get::<TcpSocket>(self.tcp_handle).state();
//Close TCP socket if necessary
if tcp_state == TcpState::Established && tls_state == TlsState::DEFAULT {
self.sockets.get::<TcpSocket>(self.tcp_handle).close();
return Ok(false);
}
// Skip handshake processing if it is already completed
// However, redo TCP handshake if TLS socket is trying to connect and
// TCP socket is not connected
@ -173,6 +181,117 @@ impl<'a, 'b, 'c> TlsSocket<'a, 'b, 'c> {
return Ok(false);
}
}
// Send alert to start terminating TLS session if necessary
if let Some(alert) = need_send_alert {
match tls_state {
// Client side socket:
// States that expects plaintext payload
TlsState::WAIT_SH | TlsState::SERVER_START => {
// Send the cooresponding alert in plaintext
let mut tcp_socket = self.sockets.get::<TcpSocket>(self.tcp_handle);
tcp_socket.send(
|data| {
// Set up a TLS buffer on the internal buffer of TCP socket
let mut buffer = TlsBuffer::new(data);
// Instantiate a TLS bytes-representation with pre-determined alert
let tls_repr = TlsRepr::new().alert(alert);
if buffer.enqueue_tls_repr(tls_repr).is_err() {
return (0, ())
}
let slice: &[u8] = buffer.into();
(slice.len(), ())
}
)?;
},
// States that expects enrypted payload using handshake secret
TlsState::WAIT_EE |
TlsState::WAIT_CERT_CR |
TlsState::CLIENT_WAIT_CERT |
TlsState::CLIENT_WAIT_CV |
TlsState::CLIENT_WAIT_FINISHED |
TlsState::SERVER_COMPLETED |
TlsState::NEGOTIATED |
TlsState::WAIT_FLIGHT |
TlsState::SERVER_WAIT_CERT |
TlsState::SERVER_WAIT_CV => {
// Send the corresponding alert in ciphertext using handshake secret
let severity: u8 = match alert {
AlertType::CloseNotify | AlertType::UserCanceled => {
1
},
_ => 2
};
let mut alert_array: [u8; 3] = [
severity,
u8::try_from(alert).unwrap(),
21 // Alert content type
];
self.send_application_slice(&mut alert_array)?;
},
// States that expects enrypted payload using application data secret
TlsState::CLIENT_CONNECTED |
TlsState::SERVER_WAIT_FINISHED |
TlsState::SERVER_CONNECTED => {
// Send the corresponding alert in ciphertext using application data secret
// Sending order:
// 1. Associated data/ TLS Record layer
// 2. Encrypted { Alert }
// 3. Authentication tag (16 bytes for all supported AEADs)
let mut associated_data: [u8; 5] = [
0x17, // Application data
0x03, 0x03, // TLS 1.3 record disguised as TLS 1.2
0x00, 0x00 // Length of encrypted data, yet to be determined conveniently
];
NetworkEndian::write_u16(&mut associated_data[3..5],
2 // Payload length
+ 1 // Content type length
+ 16 // Auth tag length
);
// Alert: Warning (1) , Close notify (0)
let severity: u8 = match alert {
AlertType::CloseNotify | AlertType::UserCanceled => {
1
},
_ => 2
};
let mut alert_array: [u8; 3] = [
severity,
u8::try_from(alert).unwrap(),
21 // Alert content type
];
let mut session = self.session.borrow_mut();
let tag = session.encrypt_application_data_in_place_detached(
&associated_data,
&mut alert_array
).unwrap();
session.increment_local_sequence_number();
let mut tcp_socket = self.sockets.get::<TcpSocket>(self.tcp_handle);
if !tcp_socket.can_send() {
return Err(Error::Illegal);
}
tcp_socket.send_slice(&associated_data)?;
tcp_socket.send_slice(&alert_array)?;
tcp_socket.send_slice(&tag)?;
},
// Other states, such as client_start and default should never send alert
// These stages are too early to raise exceptions
_ => unreachable!()
}
// Finally, revert the FSM to DEFAULT to signal an invokation of
// `close()` to the TCP socket
self.session.borrow_mut().reset_state();
return Ok(false);
}
// Handle TLS handshake through TLS states
match tls_state {
// Do nothing on the default state
@ -654,13 +773,6 @@ impl<'a, 'b, 'c> TlsSocket<'a, 'b, 'c> {
return Ok(true);
}
// Terminate TLS connection with an alert
// Terminate TCP session by issuing `close()`
// Reset the socket
TlsState::NEED_RESET(alert) => {
todo!()
}
// Other states
_ => {}
}
@ -1716,6 +1828,34 @@ impl<'a, 'b, 'c> TlsSocket<'a, 'b, 'c> {
Ok(())
}
// Send `Close notify` alert to remote side
// Set state to `CLOSED`
// Leave TCP termination to polling method
pub fn close(&mut self) -> Result<()> {
let mut session = self.session.borrow_mut();
match session.get_tls_state() {
// Send a `close notify` if handshake is established
TlsState::CLIENT_CONNECTED | TlsState::SERVER_CONNECTED => {
session.invalidate_session(
AlertType::CloseNotify,
&[]
);
},
// Do nothing if handshake hasn't even started
TlsState::DEFAULT => {},
// Send `user cancaled` to cancel the handshake negotiation
// if it is currently in the middle of one
_ => {
session.invalidate_session(
AlertType::UserCanceled,
&[]
);
}
}
Ok(())
}
}
use core::fmt;