ring/aead/poly1305/
ffi_fallback.rs

1// Copyright 2015-2025 Brian Smith.
2// Portions Copyright (c) 2014, 2015, Google Inc.
3//
4// Permission to use, copy, modify, and/or distribute this software for any
5// purpose with or without fee is hereby granted, provided that the above
6// copyright notice and this permission notice appear in all copies.
7//
8// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
11// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
13// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
14// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15
16use super::{Key, Tag, KEY_LEN, TAG_LEN};
17use crate::c;
18use core::num::NonZeroUsize;
19
20// XXX/TODO(MSRV): change to `pub(super)`.
21pub(in super::super) struct State {
22    state: poly1305_state_st,
23}
24
25// Keep in sync with `poly1305_state_st` in poly1305.c
26#[repr(C, align(64))]
27struct poly1305_state_st {
28    r0: u32,
29    r1: u32,
30    r2: u32,
31    r3: u32,
32    r4: u32,
33    s1: u32,
34    s2: u32,
35    s3: u32,
36    s4: u32,
37    h0: u32,
38    h1: u32,
39    h2: u32,
40    h3: u32,
41    h4: u32,
42    key: [u8; 16],
43}
44
45impl State {
46    pub(super) fn new_context(Key { key_and_nonce }: Key) -> super::Context {
47        prefixed_extern! {
48            fn CRYPTO_poly1305_init(state: &mut poly1305_state_st, key: &[u8; KEY_LEN]);
49        }
50        let mut r = Self {
51            state: poly1305_state_st {
52                r0: 0,
53                r1: 0,
54                r2: 0,
55                r3: 0,
56                r4: 0,
57                s1: 0,
58                s2: 0,
59                s3: 0,
60                s4: 0,
61                h0: 0,
62                h1: 0,
63                h2: 0,
64                h3: 0,
65                h4: 0,
66                key: [0u8; 16],
67            },
68        };
69        unsafe { CRYPTO_poly1305_init(&mut r.state, &key_and_nonce) }
70        super::Context::Fallback(r)
71    }
72
73    // `input.len % BLOCK_LEN == 0` must be true for every call except the
74    // final one.
75    pub(super) fn update_internal(&mut self, input: &[u8]) {
76        prefixed_extern! {
77            fn CRYPTO_poly1305_update(
78                state: &mut poly1305_state_st,
79                input: *const u8,
80                in_len: c::NonZero_size_t);
81        }
82        if let Some(len) = NonZeroUsize::new(input.len()) {
83            let input = input.as_ptr();
84            unsafe { CRYPTO_poly1305_update(&mut self.state, input, len) }
85        }
86    }
87
88    pub(super) fn finish(mut self) -> Tag {
89        prefixed_extern! {
90            fn CRYPTO_poly1305_finish(statep: &mut poly1305_state_st, mac: &mut [u8; TAG_LEN]);
91        }
92        let mut tag = Tag([0u8; TAG_LEN]);
93        unsafe { CRYPTO_poly1305_finish(&mut self.state, &mut tag.0) }
94        tag
95    }
96}
ring/aead/poly1305/ffi_fallback.rs

ring/aead/poly1305/
ffi_fallback.rs
