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Remove default max recv size

This commit is contained in:
Matéo Duparc 2021-06-18 19:24:57 +02:00
parent a6f194092c
commit 904e53f6de
Signed by: hardcoresushi
GPG Key ID: 007F84120107191E
2 changed files with 31 additions and 32 deletions
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54
src/lib.rs
View File

@ -60,9 +60,6 @@ const RANDOM_LEN: usize = 64;
const MESSAGE_LEN_LEN: usize = 4;
type MessageLenType = u32;
const DEFAULT_PADDED_MAX_SIZE: usize = 32768000;
const DEFAULT_MAX_RECV_SIZE: usize = MESSAGE_LEN_LEN + DEFAULT_PADDED_MAX_SIZE + AES_TAG_LEN;
/// The length of a PSEC public key, in bytes.
pub const PUBLIC_KEY_LENGTH: usize = ed25519_dalek::PUBLIC_KEY_LENGTH;
@ -187,27 +184,28 @@ async fn encrypt_and_send<T: AsyncWriteExt + Unpin>(writer: &mut T, local_cipher
send(writer, &cipher_text).await
}
async fn receive_and_decrypt<T: AsyncReadExt + Unpin>(reader: &mut T, peer_cipher: &Aes128Gcm, peer_iv: &[u8], peer_counter: &mut usize, max_recv_size: usize) -> Result<Vec<u8>, PsecError> {
async fn receive_and_decrypt<T: AsyncReadExt + Unpin>(reader: &mut T, peer_cipher: &Aes128Gcm, peer_iv: &[u8], peer_counter: &mut usize, max_recv_size: Option<usize>) -> Result<Vec<u8>, PsecError> {
let mut message_len = [0; MESSAGE_LEN_LEN];
receive(reader, &mut message_len).await?;
let recv_len = MessageLenType::from_be_bytes(message_len) as usize + AES_TAG_LEN;
if recv_len <= max_recv_size {
let mut cipher_text = vec![0; recv_len];
let mut read = 0;
while read < recv_len {
read += receive(reader, &mut cipher_text[read..]).await?;
if let Some(max_recv_size) = max_recv_size {
if recv_len > max_recv_size {
return Err(PsecError::BufferTooLarge);
}
let peer_nonce = crypto::iv_to_nonce(peer_iv, peer_counter);
let payload = Payload {
msg: &cipher_text,
aad: &message_len
};
match peer_cipher.decrypt(Nonce::from_slice(&peer_nonce), payload) {
Ok(plain_text) => unpad(plain_text),
Err(_) => Err(PsecError::TransmissionCorrupted)
}
} else {
Err(PsecError::BufferTooLarge)
}
let mut cipher_text = vec![0; recv_len];
let mut read = 0;
while read < recv_len {
read += receive(reader, &mut cipher_text[read..]).await?;
}
let peer_nonce = crypto::iv_to_nonce(peer_iv, peer_counter);
let payload = Payload {
msg: &cipher_text,
aad: &message_len
};
match peer_cipher.decrypt(Nonce::from_slice(&peer_nonce), payload) {
Ok(plain_text) => unpad(plain_text),
Err(_) => Err(PsecError::TransmissionCorrupted)
}
}
@ -231,9 +229,7 @@ pub trait PsecReader {
Any received buffer larger than this value will be discarded and a [`BufferTooLarge`](PsecError::BufferTooLarge) error will be returned. Then, the PSEC session should be closed to prevent any DOS attacks.
If `is_raw_size` is set to `true`, the specified `size` will correspond to the maximum encrypted buffer size, including potential padding. Otherwise, the maximum buffer size will correspond to the length of a message of this size after applying padding and encryption.
The default value is 32 768 020, which allows to receive any messages under 32 768 000 bytes.*/
If `is_raw_size` is set to `true`, the specified `size` will correspond to the maximum encrypted buffer size, including potential padding. Otherwise, the maximum buffer size will correspond to the length of a message of this size after applying padding and encryption.*/
fn set_max_recv_size(&mut self, size: usize, is_raw_size: bool);
/** Read then decrypt from a PSEC session.
@ -282,7 +278,7 @@ pub trait PsecReader {
pub trait PsecWriter {
/** Encrypt then send through a PSEC session.
`use_padding` specifies whether or not the plain text length should be obfuscated with padding. Enabling padding will use more network bandwidth: all messages below 1KB will be padded to 1KB and then the padded length doubles at each step (2KB, 4KB, 8KB...). When sending a buffer of 17MB, it will padded to 32MB.
`use_padding` specifies whether or not the plain text length should be obfuscated with padding. Enabling padding will use more network bandwidth: all messages below 1KB will be padded to 1KB and then the padded length doubles at each step (2KB, 4KB, 8KB...). For example, a buffer of 1.5KB will be padded to 2KB, and a buffer of 3KB will be padded to 4KB.
# Panic
Panics if the PSEC handshake is not finished and successful.
@ -325,7 +321,7 @@ pub struct SessionReadHalf {
peer_cipher: Aes128Gcm,
peer_iv: [u8; crypto::IV_LEN],
peer_counter: usize,
max_recv_size: usize,
max_recv_size: Option<usize>,
}
#[cfg(feature = "split")]
@ -344,7 +340,7 @@ impl Debug for SessionReadHalf {
#[async_trait]
impl PsecReader for SessionReadHalf {
fn set_max_recv_size(&mut self, size: usize, is_raw_size: bool) {
self.max_recv_size = compute_max_recv_size(size, is_raw_size)
self.max_recv_size = Some(compute_max_recv_size(size, is_raw_size));
}
async fn receive_and_decrypt(&mut self) -> Result<Vec<u8>, PsecError> {
receive_and_decrypt(&mut self.read_half, &self.peer_cipher, &self.peer_iv, &mut self.peer_counter, self.max_recv_size).await
@ -397,7 +393,7 @@ pub struct Session {
peer_cipher: Option<Aes128Gcm>,
peer_iv: Option<[u8; crypto::IV_LEN]>,
peer_counter: usize,
max_recv_size: usize,
max_recv_size: Option<usize>,
/** The public key of the remote peer.
It is `None` before the PSEC handshake was performed. After a successful call to [`do_handshake`](Session::do_handshake), the field is `Some`. If the handshake was not successful, the field can be either `Some` or `None` depending on where the handshake failed.
@ -611,7 +607,7 @@ impl PsecWriter for Session {
#[async_trait]
impl PsecReader for Session {
fn set_max_recv_size(&mut self, size: usize, is_raw_size: bool) {
self.max_recv_size = compute_max_recv_size(size, is_raw_size);
self.max_recv_size = Some(compute_max_recv_size(size, is_raw_size));
}
async fn receive_and_decrypt(&mut self) -> Result<Vec<u8>, PsecError> {
receive_and_decrypt(&mut self.stream, &self.peer_cipher.as_ref().unwrap(), &self.peer_iv.unwrap(), &mut self.peer_counter, self.max_recv_size).await
@ -632,7 +628,7 @@ impl From<TcpStream> for Session {
peer_iv: None,
peer_counter: 0,
peer_public_key: None,
max_recv_size: DEFAULT_MAX_RECV_SIZE,
max_recv_size: None,
}
}
}

9
tests/psec_test.rs
View File

@ -11,7 +11,7 @@ async fn tokio_main() {
let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
let bind_addr = listener.local_addr().unwrap();
tokio::spawn(async move {
let handle = tokio::spawn(async move {
let (stream, addr) = listener.accept().await.unwrap();
let mut session = Session::from(stream);
@ -23,7 +23,7 @@ async fn tokio_main() {
session.encrypt_and_send(b"Hello I'm Bob", true).await.unwrap();
assert_eq!(session.receive_and_decrypt().await.unwrap(), b"Hello I'm Alice");
session.encrypt_and_send("!".repeat(997).as_bytes(), false).await.unwrap();
session.encrypt_and_send("!".repeat(997).as_bytes(), true).await.unwrap();
assert_eq!(session.receive_and_decrypt().await, Err(PsecError::TransmissionCorrupted));
});
@ -36,13 +36,16 @@ async fn tokio_main() {
session.do_handshake(&client_keypair).await.unwrap();
assert_eq!(session.peer_public_key.unwrap(), server_public_key);
session.set_max_recv_size(996, false);
session.encrypt_and_send(b"Hello I'm Alice", true).await.unwrap();
assert_eq!(session.receive_and_decrypt().await.unwrap(), b"Hello I'm Bob");
session.set_max_recv_size(1, false);
assert_eq!(session.receive_and_decrypt().await, Err(PsecError::BufferTooLarge));
session.send(b"\x00\x00\x00\x00not encrypted data").await.unwrap();
handle.await.unwrap();
}
#[test]