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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::{
fmt,
ops::{Deref, DerefMut},
os::raw::{c_char, c_uint},
ptr::null_mut,
};
use crate::{
constants::{Cipher, Version},
err::Res,
experimental_api,
p11::{PK11SymKey, SymKey},
scoped_ptr,
ssl::{self, PRUint16, PRUint64, PRUint8, SSLAeadContext},
};
experimental_api!(SSL_MakeAead(
version: PRUint16,
cipher: PRUint16,
secret: *mut PK11SymKey,
label_prefix: *const c_char,
label_prefix_len: c_uint,
ctx: *mut *mut SSLAeadContext,
));
experimental_api!(SSL_AeadEncrypt(
ctx: *const SSLAeadContext,
counter: PRUint64,
aad: *const PRUint8,
aad_len: c_uint,
input: *const PRUint8,
input_len: c_uint,
output: *const PRUint8,
output_len: *mut c_uint,
max_output: c_uint
));
experimental_api!(SSL_AeadDecrypt(
ctx: *const SSLAeadContext,
counter: PRUint64,
aad: *const PRUint8,
aad_len: c_uint,
input: *const PRUint8,
input_len: c_uint,
output: *const PRUint8,
output_len: *mut c_uint,
max_output: c_uint
));
experimental_api!(SSL_DestroyAead(ctx: *mut SSLAeadContext));
scoped_ptr!(AeadContext, SSLAeadContext, SSL_DestroyAead);
pub struct RealAead {
ctx: AeadContext,
}
impl RealAead {
/// Create a new AEAD based on the indicated TLS version and cipher suite.
///
/// # Errors
///
/// Returns `Error` when the supporting NSS functions fail.
pub fn new(version: Version, cipher: Cipher, secret: &SymKey, prefix: &str) -> Res<Self> {
let s: *mut PK11SymKey = **secret;
unsafe { Self::from_raw(version, cipher, s, prefix) }
}
#[must_use]
#[allow(clippy::unused_self)]
pub fn expansion(&self) -> usize {
16
}
unsafe fn from_raw(
version: Version,
cipher: Cipher,
secret: *mut PK11SymKey,
prefix: &str,
) -> Res<Self> {
let p = prefix.as_bytes();
let mut ctx: *mut ssl::SSLAeadContext = null_mut();
SSL_MakeAead(
version,
cipher,
secret,
p.as_ptr().cast(),
c_uint::try_from(p.len())?,
&mut ctx,
)?;
Ok(Self {
ctx: AeadContext::from_ptr(ctx)?,
})
}
/// Encrypt a plaintext.
///
/// The space provided in `output` needs to be larger than `input` by
/// the value provided in `Aead::expansion`.
///
/// # Errors
///
/// If the input can't be protected or any input is too large for NSS.
pub fn encrypt<'a>(
&self,
count: u64,
aad: &[u8],
input: &[u8],
output: &'a mut [u8],
) -> Res<&'a [u8]> {
let mut l: c_uint = 0;
unsafe {
SSL_AeadEncrypt(
*self.ctx,
count,
aad.as_ptr(),
c_uint::try_from(aad.len())?,
input.as_ptr(),
c_uint::try_from(input.len())?,
output.as_mut_ptr(),
&mut l,
c_uint::try_from(output.len())?,
)
}?;
Ok(&output[0..(l.try_into()?)])
}
/// Decrypt a ciphertext.
///
/// Note that NSS insists upon having extra space available for decryption, so
/// the buffer for `output` should be the same length as `input`, even though
/// the final result will be shorter.
///
/// # Errors
///
/// If the input isn't authenticated or any input is too large for NSS.
pub fn decrypt<'a>(
&self,
count: u64,
aad: &[u8],
input: &[u8],
output: &'a mut [u8],
) -> Res<&'a [u8]> {
let mut l: c_uint = 0;
unsafe {
SSL_AeadDecrypt(
*self.ctx,
count,
aad.as_ptr(),
c_uint::try_from(aad.len())?,
input.as_ptr(),
c_uint::try_from(input.len())?,
output.as_mut_ptr(),
&mut l,
c_uint::try_from(output.len())?,
)
}?;
Ok(&output[0..(l.try_into()?)])
}
}
impl fmt::Debug for RealAead {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "[AEAD Context]")
}
}