vpncloud/src/crypto.rs

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// VpnCloud - Peer-to-Peer VPN
// Copyright (C) 2015-2016 Dennis Schwerdel
// This software is licensed under GPL-3 or newer (see LICENSE.md)
use std::ptr;
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use std::ffi::CStr;
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use std::sync::{Once, ONCE_INIT};
static CRYPTO_INIT: Once = ONCE_INIT;
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use libc::{size_t, c_char, c_ulonglong, c_int};
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use aligned_alloc::{aligned_alloc, aligned_free};
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use super::types::Error;
#[allow(non_upper_case_globals)]
const crypto_aead_chacha20poly1305_ietf_KEYBYTES: usize = 32;
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#[allow(non_upper_case_globals)]
const crypto_aead_chacha20poly1305_ietf_NSECBYTES: usize = 0;
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#[allow(non_upper_case_globals)]
const crypto_aead_chacha20poly1305_ietf_NPUBBYTES: usize = 12;
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#[allow(non_upper_case_globals)]
const crypto_aead_chacha20poly1305_ietf_ABYTES: usize = 16;
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#[allow(non_upper_case_globals)]
const crypto_aead_aes256gcm_KEYBYTES: usize = 32;
#[allow(non_upper_case_globals)]
const crypto_aead_aes256gcm_NSECBYTES: usize = 0;
#[allow(non_upper_case_globals)]
const crypto_aead_aes256gcm_NPUBBYTES: usize = 12;
#[allow(non_upper_case_globals)]
const crypto_aead_aes256gcm_ABYTES: usize = 16;
#[allow(non_upper_case_globals)]
const crypto_aead_aes256gcm_STATEBYTES: usize = 512;
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#[allow(non_upper_case_globals)]
const crypto_pwhash_scryptsalsa208sha256_SALTBYTES: usize = 32;
#[allow(non_upper_case_globals)]
const crypto_pwhash_scryptsalsa208sha256_STRBYTES: usize = 102;
#[allow(non_upper_case_globals)]
const crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE: usize = 524288;
#[allow(non_upper_case_globals)]
const crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE: usize = 16777216;
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pub struct Aes256State(*mut [u8; crypto_aead_aes256gcm_STATEBYTES]);
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impl Aes256State {
fn new() -> Aes256State {
let ptr = aligned_alloc(crypto_aead_aes256gcm_STATEBYTES, 16)
as *mut [u8; crypto_aead_aes256gcm_STATEBYTES];
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Aes256State(ptr)
}
}
impl Drop for Aes256State {
fn drop(&mut self) {
unsafe { aligned_free(self.0 as *mut ()) }
}
}
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#[link(name="sodium", kind="static")]
extern {
pub fn sodium_init() -> c_int;
pub fn randombytes_buf(buf: *mut u8, size: size_t);
pub fn sodium_version_string() -> *const c_char;
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pub fn crypto_aead_aes256gcm_is_available() -> c_int;
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pub fn crypto_pwhash_scryptsalsa208sha256(
out: *mut u8,
outlen: c_ulonglong,
passwd: *const u8,
passwdlen: c_ulonglong,
salt: *const [u8; crypto_pwhash_scryptsalsa208sha256_SALTBYTES],
opslimit: c_ulonglong,
memlimit: size_t) -> c_int;
pub fn crypto_aead_chacha20poly1305_ietf_encrypt(
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c: *mut u8,
clen: *mut c_ulonglong,
m: *const u8,
mlen: c_ulonglong,
ad: *const u8,
adlen: c_ulonglong,
nsec: *const [u8; crypto_aead_chacha20poly1305_ietf_NSECBYTES],
npub: *const [u8; crypto_aead_chacha20poly1305_ietf_NPUBBYTES],
k: *const [u8; crypto_aead_chacha20poly1305_ietf_KEYBYTES]) -> c_int;
pub fn crypto_aead_chacha20poly1305_ietf_decrypt(
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m: *mut u8,
mlen: *mut c_ulonglong,
nsec: *mut [u8; crypto_aead_chacha20poly1305_ietf_NSECBYTES],
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c: *const u8,
clen: c_ulonglong,
ad: *const u8,
adlen: c_ulonglong,
npub: *const [u8; crypto_aead_chacha20poly1305_ietf_NPUBBYTES],
k: *const [u8; crypto_aead_chacha20poly1305_ietf_KEYBYTES]) -> c_int;
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pub fn crypto_aead_aes256gcm_beforenm(
state: *mut [u8; crypto_aead_aes256gcm_STATEBYTES],
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k: *const [u8; crypto_aead_aes256gcm_KEYBYTES]) -> c_int;
pub fn crypto_aead_aes256gcm_encrypt_afternm(
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c: *mut u8,
clen: *mut c_ulonglong,
m: *const u8,
mlen: c_ulonglong,
ad: *const u8,
adlen: c_ulonglong,
nsec: *const [u8; crypto_aead_aes256gcm_NSECBYTES],
npub: *const [u8; crypto_aead_aes256gcm_NPUBBYTES],
state: *const [u8; crypto_aead_aes256gcm_STATEBYTES]) -> c_int;
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pub fn crypto_aead_aes256gcm_decrypt_afternm(
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m: *mut u8,
mlen: *mut c_ulonglong,
nsec: *mut [u8; crypto_aead_aes256gcm_NSECBYTES],
c: *const u8,
clen: c_ulonglong,
ad: *const u8,
adlen: c_ulonglong,
npub: *const [u8; crypto_aead_aes256gcm_NPUBBYTES],
state: *const [u8; crypto_aead_aes256gcm_STATEBYTES]) -> c_int;
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}
#[derive(RustcDecodable, Debug)]
pub enum CryptoMethod {
ChaCha20, AES256
}
pub enum Crypto {
None,
ChaCha20Poly1305{
key: [u8; crypto_aead_chacha20poly1305_ietf_KEYBYTES],
nonce: [u8; crypto_aead_chacha20poly1305_ietf_NPUBBYTES]
},
AES256GCM{
state: Aes256State,
nonce: [u8; crypto_aead_aes256gcm_NPUBBYTES]
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}
}
fn inc_nonce_12(nonce: &mut [u8; 12]) {
for i in 0..12 {
let mut num = nonce[11-i];
num = num.wrapping_add(1);
nonce[11-i] = num;
if num > 0 {
break
}
}
}
impl Crypto {
pub fn init() {
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CRYPTO_INIT.call_once(|| {
if unsafe { sodium_init() } != 0 {
fail!("Failed to initialize crypto library");
}
});
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}
pub fn sodium_version() -> String {
unsafe {
CStr::from_ptr(sodium_version_string()).to_string_lossy().to_string()
}
}
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pub fn aes256_available() -> bool {
unsafe {
crypto_aead_aes256gcm_is_available() == 1
}
}
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pub fn method(&self) -> u8 {
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match *self {
Crypto::None => 0,
Crypto::ChaCha20Poly1305{..} => 1,
Crypto::AES256GCM{..} => 2
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}
}
pub fn nonce_bytes(&self) -> usize {
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match *self {
Crypto::None => 0,
Crypto::ChaCha20Poly1305{ref nonce, ..} => nonce.len(),
Crypto::AES256GCM{ref nonce, ..} => nonce.len()
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}
}
pub fn additional_bytes(&self) -> usize {
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match *self {
Crypto::None => 0,
Crypto::ChaCha20Poly1305{..} => crypto_aead_chacha20poly1305_ietf_ABYTES,
Crypto::AES256GCM{..} => crypto_aead_aes256gcm_ABYTES
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}
}
pub fn from_shared_key(method: CryptoMethod, password: &str) -> Self {
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let salt = b"vpncloudVPNCLOUDvpncl0udVpnCloud";
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assert_eq!(salt.len(), crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
let mut key = [0; crypto_pwhash_scryptsalsa208sha256_STRBYTES];
let res = unsafe { crypto_pwhash_scryptsalsa208sha256(
key.as_mut_ptr(),
key.len() as u64,
password.as_bytes().as_ptr(),
password.as_bytes().len() as u64,
salt.as_ptr() as *const [u8; crypto_pwhash_scryptsalsa208sha256_SALTBYTES],
crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE as u64,
crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE
) };
if res != 0 {
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fail!("Key derivation failed");
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}
match method {
CryptoMethod::ChaCha20 => {
let mut crypto_key = [0; crypto_aead_chacha20poly1305_ietf_KEYBYTES];
crypto_key.clone_from_slice(&key[..crypto_aead_chacha20poly1305_ietf_KEYBYTES]);
let mut nonce = [0u8; crypto_aead_chacha20poly1305_ietf_NPUBBYTES];
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unsafe { randombytes_buf(nonce.as_mut_ptr(), nonce.len()) };
Crypto::ChaCha20Poly1305{key: crypto_key, nonce: nonce}
},
CryptoMethod::AES256 => {
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if ! Crypto::aes256_available() {
fail!("AES256 is not supported by this processor, use ChaCha20 instead");
}
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let mut nonce = [0u8; crypto_aead_aes256gcm_NPUBBYTES];
unsafe { randombytes_buf(nonce.as_mut_ptr(), nonce.len()) };
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let state = Aes256State::new();
let res = unsafe { crypto_aead_aes256gcm_beforenm(
state.0,
key[..crypto_aead_aes256gcm_KEYBYTES].as_ptr() as *const [u8; crypto_aead_aes256gcm_KEYBYTES]
) };
assert_eq!(res, 0);
Crypto::AES256GCM{state: state, nonce: nonce}
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}
}
}
pub fn decrypt(&self, mut buf: &mut [u8], nonce: &[u8], header: &[u8]) -> Result<usize, Error> {
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match *self {
Crypto::None => Ok(buf.len()),
Crypto::ChaCha20Poly1305{ref key, ..} => {
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let mut mlen: u64 = buf.len() as u64;
let res = unsafe { crypto_aead_chacha20poly1305_ietf_decrypt(
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buf.as_mut_ptr(), // Base pointer to buffer
&mut mlen, // Mutable size of buffer (will be set to used size)
ptr::null_mut::<[u8; 0]>(), // Mutable base pointer to secret nonce (always NULL)
buf.as_ptr(), // Base pointer to message
buf.len() as u64, // Size of message
header.as_ptr(), // Base pointer to additional data
header.len() as u64, // Size of additional data
nonce.as_ptr() as *const [u8; crypto_aead_chacha20poly1305_ietf_NPUBBYTES], // Base pointer to public nonce
key.as_ptr() as *const [u8; crypto_aead_chacha20poly1305_ietf_KEYBYTES] // Base pointer to key
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) };
match res {
0 => Ok(mlen as usize),
_ => Err(Error::CryptoError("Failed to decrypt"))
}
},
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Crypto::AES256GCM{ref state, ..} => {
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let mut mlen: u64 = buf.len() as u64;
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let res = unsafe { crypto_aead_aes256gcm_decrypt_afternm(
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buf.as_mut_ptr(), // Base pointer to buffer
&mut mlen, // Mutable size of buffer (will be set to used size)
ptr::null_mut::<[u8; 0]>(), // Mutable base pointer to secret nonce (always NULL)
buf.as_ptr(), // Base pointer to message
buf.len() as u64, // Size of message
header.as_ptr(), // Base pointer to additional data
header.len() as u64, // Size of additional data
nonce.as_ptr() as *const [u8; crypto_aead_aes256gcm_NPUBBYTES], // Base pointer to public nonce
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state.0 // Base pointer to state
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) };
match res {
0 => Ok(mlen as usize),
_ => Err(Error::CryptoError("Failed to decrypt"))
}
}
}
}
pub fn encrypt(&mut self, mut buf: &mut [u8], mlen: usize, nonce_bytes: &mut [u8], header: &[u8]) -> usize {
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match *self {
Crypto::None => mlen,
Crypto::ChaCha20Poly1305{ref key, ref mut nonce} => {
inc_nonce_12(nonce);
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let mut clen: u64 = buf.len() as u64;
assert!(nonce_bytes.len() == nonce.len());
assert!(clen as usize >= mlen + crypto_aead_chacha20poly1305_ietf_ABYTES);
let res = unsafe { crypto_aead_chacha20poly1305_ietf_encrypt(
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buf.as_mut_ptr(), // Base pointer to buffer
&mut clen, // Mutable size of buffer (will be set to used size)
buf.as_ptr(), // Base pointer to message
mlen as u64, // Size of message
header.as_ptr(), // Base pointer to additional data
header.len() as u64, // Size of additional data
ptr::null::<[u8; 0]>(), // Base pointer to secret nonce (always NULL)
nonce.as_ptr() as *const [u8; crypto_aead_chacha20poly1305_ietf_NPUBBYTES], // Base pointer to public nonce
key.as_ptr() as *const [u8; crypto_aead_chacha20poly1305_ietf_KEYBYTES] // Base pointer to key
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) };
assert_eq!(res, 0);
unsafe {
ptr::copy_nonoverlapping(nonce.as_ptr(), nonce_bytes.as_mut_ptr(), nonce.len());
}
clen as usize
},
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Crypto::AES256GCM{ref state, ref mut nonce} => {
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inc_nonce_12(nonce);
let mut clen: u64 = buf.len() as u64;
assert!(nonce_bytes.len() == nonce.len());
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assert!(clen as usize >= mlen + crypto_aead_aes256gcm_ABYTES);
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let res = unsafe { crypto_aead_aes256gcm_encrypt_afternm(
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buf.as_mut_ptr(), // Base pointer to buffer
&mut clen, // Mutable size of buffer (will be set to used size)
buf.as_ptr(), // Base pointer to message
mlen as u64, // Size of message
header.as_ptr(), // Base pointer to additional data
header.len() as u64, // Size of additional data
ptr::null::<[u8; 0]>(), // Base pointer to secret nonce (always NULL)
nonce.as_ptr() as *const [u8; crypto_aead_aes256gcm_NPUBBYTES], // Base pointer to public nonce
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state.0 // Base pointer to state
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) };
assert_eq!(res, 0);
unsafe {
ptr::copy_nonoverlapping(nonce.as_ptr(), nonce_bytes.as_mut_ptr(), nonce.len());
}
clen as usize
}
}
}
}