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 AUTHORS DISCLAIM ALL WARRANTIES
9// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS 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}
97