1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::{
cell::RefCell,
fmt::{self, Debug},
os::raw::{c_char, c_int, c_uint},
ptr::{addr_of_mut, null, null_mut},
rc::Rc,
};
use crate::{
constants::{
Cipher, Version, TLS_AES_128_GCM_SHA256, TLS_AES_256_GCM_SHA384,
TLS_CHACHA20_POLY1305_SHA256,
},
err::{secstatus_to_res, Error, Res},
p11::{
Context, Item, PK11SymKey, PK11_CipherOp, PK11_CreateContextBySymKey, PK11_Encrypt,
PK11_GetBlockSize, SymKey, CKA_ENCRYPT, CKM_AES_ECB, CKM_CHACHA20, CK_ATTRIBUTE_TYPE,
CK_CHACHA20_PARAMS, CK_MECHANISM_TYPE,
},
};
experimental_api!(SSL_HkdfExpandLabelWithMech(
version: Version,
cipher: Cipher,
prk: *mut PK11SymKey,
handshake_hash: *const u8,
handshake_hash_len: c_uint,
label: *const c_char,
label_len: c_uint,
mech: CK_MECHANISM_TYPE,
key_size: c_uint,
secret: *mut *mut PK11SymKey,
));
#[derive(Clone)]
pub enum HpKey {
/// An AES encryption context.
/// Note: as we need to clone this object, we clone the pointer and
/// track references using `Rc`. `PK11Context` can't be used with `PK11_CloneContext`
/// as that is not supported for these contexts.
Aes(Rc<RefCell<Context>>),
/// The `ChaCha20` mask has to invoke a new `PK11_Encrypt` every time as it needs to
/// change the counter and nonce on each invocation.
Chacha(SymKey),
}
impl Debug for HpKey {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "HpKey")
}
}
impl HpKey {
const SAMPLE_SIZE: usize = 16;
/// QUIC-specific API for extracting a header-protection key.
///
/// # Errors
///
/// Errors if HKDF fails or if the label is too long to fit in a `c_uint`.
///
/// # Panics
///
/// When `cipher` is not known to this code.
#[allow(clippy::cast_sign_loss)] // Cast for PK11_GetBlockSize is safe.
pub fn extract(version: Version, cipher: Cipher, prk: &SymKey, label: &str) -> Res<Self> {
const ZERO: &[u8] = &[0; 12];
let l = label.as_bytes();
let mut secret: *mut PK11SymKey = null_mut();
let (mech, key_size) = match cipher {
TLS_AES_128_GCM_SHA256 => (CK_MECHANISM_TYPE::from(CKM_AES_ECB), 16),
TLS_AES_256_GCM_SHA384 => (CK_MECHANISM_TYPE::from(CKM_AES_ECB), 32),
TLS_CHACHA20_POLY1305_SHA256 => (CK_MECHANISM_TYPE::from(CKM_CHACHA20), 32),
_ => unreachable!(),
};
// Note that this doesn't allow for passing null() for the handshake hash.
// A zero-length slice produces an identical result.
unsafe {
SSL_HkdfExpandLabelWithMech(
version,
cipher,
**prk,
null(),
0,
l.as_ptr().cast(),
c_uint::try_from(l.len())?,
mech,
key_size,
&mut secret,
)
}?;
let key = SymKey::from_ptr(secret).or(Err(Error::HkdfError))?;
let res = match cipher {
TLS_AES_128_GCM_SHA256 | TLS_AES_256_GCM_SHA384 => {
let context_ptr = unsafe {
PK11_CreateContextBySymKey(
mech,
CK_ATTRIBUTE_TYPE::from(CKA_ENCRYPT),
*key,
&Item::wrap(&ZERO[..0]), // Borrow a zero-length slice of ZERO.
)
};
let context = Context::from_ptr(context_ptr).or(Err(Error::CipherInitFailure))?;
Self::Aes(Rc::new(RefCell::new(context)))
}
TLS_CHACHA20_POLY1305_SHA256 => Self::Chacha(key),
_ => unreachable!(),
};
debug_assert_eq!(
res.block_size(),
usize::try_from(unsafe { PK11_GetBlockSize(mech, null_mut()) }).unwrap()
);
Ok(res)
}
/// Get the sample size, which is also the output size.
#[must_use]
#[allow(clippy::unused_self)] // To maintain an API contract.
pub fn sample_size(&self) -> usize {
Self::SAMPLE_SIZE
}
fn block_size(&self) -> usize {
match self {
Self::Aes(_) => 16,
Self::Chacha(_) => 64,
}
}
/// Generate a header protection mask for QUIC.
///
/// # Errors
///
/// An error is returned if the NSS functions fail; a sample of the
/// wrong size is the obvious cause.
///
/// # Panics
///
/// When the mechanism for our key is not supported.
pub fn mask(&self, sample: &[u8]) -> Res<Vec<u8>> {
let mut output = vec![0_u8; self.block_size()];
match self {
Self::Aes(context) => {
let mut output_len: c_int = 0;
secstatus_to_res(unsafe {
PK11_CipherOp(
**context.borrow_mut(),
output.as_mut_ptr(),
&mut output_len,
c_int::try_from(output.len())?,
sample[..Self::SAMPLE_SIZE].as_ptr().cast(),
c_int::try_from(Self::SAMPLE_SIZE).unwrap(),
)
})?;
assert_eq!(usize::try_from(output_len).unwrap(), output.len());
Ok(output)
}
Self::Chacha(key) => {
let params: CK_CHACHA20_PARAMS = CK_CHACHA20_PARAMS {
pBlockCounter: sample.as_ptr().cast_mut(),
blockCounterBits: 32,
pNonce: sample[4..Self::SAMPLE_SIZE].as_ptr().cast_mut(),
ulNonceBits: 96,
};
let mut output_len: c_uint = 0;
let mut param_item = Item::wrap_struct(¶ms);
secstatus_to_res(unsafe {
PK11_Encrypt(
**key,
CK_MECHANISM_TYPE::from(CKM_CHACHA20),
addr_of_mut!(param_item),
output[..].as_mut_ptr(),
&mut output_len,
c_uint::try_from(output.len())?,
output[..].as_ptr(),
c_uint::try_from(output.len())?,
)
})?;
assert_eq!(usize::try_from(output_len).unwrap(), output.len());
Ok(output)
}
}
}
}
|
