crypto_ops/
lib.rs

1#![no_std]
2extern crate libc;
3
4#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
5extern {
6    pub fn rust_crypto_util_supports_aesni() -> u32;
7}
8
9#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
10pub fn supports_aesni() -> bool {
11    unsafe {
12        rust_crypto_util_supports_aesni() != 0
13    }
14}
15
16extern {
17    pub fn rust_crypto_util_fixed_time_eq_asm(
18            lhsp: *const u8,
19            rhsp: *const u8,
20            count: libc::size_t) -> u32;
21    pub fn rust_crypto_util_secure_memset(
22            dst: *mut u8,
23            val: libc::uint8_t,
24            count: libc::size_t);
25}
26
27pub fn secure_memset(dst: &mut [u8], val: u8) {
28    unsafe {
29        rust_crypto_util_secure_memset(
30            dst.as_mut_ptr(),
31            val,
32            dst.len() as libc::size_t);
33    }
34}
35
36/// Compare two vectors using a fixed number of operations. If the two vectors
37/// are not of equal length, the function returns false immediately.
38pub fn fixed_time_eq(lhs: &[u8], rhs: &[u8]) -> bool {
39    if lhs.len() != rhs.len() {
40        false
41    } else {
42        let count = lhs.len() as libc::size_t;
43
44        unsafe {
45            let lhsp = lhs.get_unchecked(0);
46            let rhsp = rhs.get_unchecked(0);
47            rust_crypto_util_fixed_time_eq_asm(lhsp, rhsp, count) == 0
48        }
49    }
50}
51
52#[cfg(test)]
53mod test {
54    use super::fixed_time_eq;
55
56    #[test]
57    pub fn test_fixed_time_eq() {
58        let a = [0, 1, 2];
59        let b = [0, 1, 2];
60        let c = [0, 1, 9];
61        let d = [9, 1, 2];
62        let e = [2, 1, 0];
63        let f = [2, 2, 2];
64        let g = [0, 0, 0];
65
66        assert!(fixed_time_eq(&a, &a));
67        assert!(fixed_time_eq(&a, &b));
68
69        assert!(!fixed_time_eq(&a, &c));
70        assert!(!fixed_time_eq(&a, &d));
71        assert!(!fixed_time_eq(&a, &e));
72        assert!(!fixed_time_eq(&a, &f));
73        assert!(!fixed_time_eq(&a, &g));
74    }
75}
crypto_ops/lib.rs

crypto_ops/
lib.rs
