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// Copyright 2018-2024 Brian Smith.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#![cfg(all(target_arch = "arm", target_endian = "little"))]
use super::{Counter, Overlapping, AES_KEY};
/// SAFETY:
/// * The caller must ensure that if blocks > 0 then either `input` and
/// `output` do not overlap at all, or input == output.add(n) for some
/// (nonnegative) n.
/// * if blocks > 0, The caller must ensure `input` points to `blocks` blocks
/// and that `output` points to writable space for `blocks` blocks.
/// * The caller must ensure that `vpaes_key` was initialized with
/// `vpaes_set_encrypt_key`.
/// * Upon returning, `blocks` blocks will have been read from `input` and
/// written to `output`.
pub(super) unsafe fn ctr32_encrypt_blocks_with_vpaes_key(
in_out: Overlapping<'_>,
vpaes_key: &AES_KEY,
ctr: &mut Counter,
) {
prefixed_extern! {
// bsaes_ctr32_encrypt_blocks requires transformation of an existing
// VPAES key; there is no `bsaes_set_encrypt_key`.
fn vpaes_encrypt_key_to_bsaes(bsaes_key: *mut AES_KEY, vpaes_key: &AES_KEY);
}
// SAFETY:
// * The caller ensures `vpaes_key` was initialized by
// `vpaes_set_encrypt_key`.
// * `bsaes_key was zeroed above, and `vpaes_encrypt_key_to_bsaes`
// is assumed to initialize `bsaes_key`.
let bsaes_key = unsafe { AES_KEY::derive(vpaes_encrypt_key_to_bsaes, vpaes_key) };
// The code for `vpaes_encrypt_key_to_bsaes` notes "vpaes stores one
// fewer round count than bsaes, but the number of keys is the same,"
// so use this as a sanity check.
debug_assert_eq!(bsaes_key.rounds(), vpaes_key.rounds() + 1);
// SAFETY:
// * `bsaes_key` is in bsaes format after calling
// `vpaes_encrypt_key_to_bsaes`.
// * `bsaes_ctr32_encrypt_blocks` satisfies the contract for
// `ctr32_encrypt_blocks`.
unsafe {
ctr32_encrypt_blocks!(bsaes_ctr32_encrypt_blocks, in_out, &bsaes_key, ctr);
}
}
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