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CBC and ECB AES modes functional.

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This commit is contained in:
Caleb Garrett 2024-02-14 22:11:38 -05:00
parent a0a8a4ec86
commit 72e4cacd91
1 changed files with 21 additions and 18 deletions
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39
embassy-stm32/src/cryp/mod.rs
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@ -3,7 +3,7 @@ use embassy_hal_internal::{into_ref, PeripheralRef};
use crate::pac;
use crate::peripherals::CRYP;
use crate::rcc::sealed::RccPeripheral;
use crate::{interrupt, Peripheral};
use crate::{interrupt, peripherals, Peripheral};
const DES_BLOCK_SIZE: usize = 8; // 64 bits
const AES_BLOCK_SIZE: usize = 16; // 128 bits
@ -49,7 +49,7 @@ pub struct Cryp<'d, T: Instance> {
_peripheral: PeripheralRef<'d, T>,
}
type InitVector<'v> = Option<&'v [u8]>;
pub type InitVector<'v> = Option<&'v [u8]>;
impl<'d, T: Instance> Cryp<'d, T> {
/// Create a new CRYP driver.
@ -88,9 +88,9 @@ impl<'d, T: Instance> Cryp<'d, T> {
ivlen = 0;
}
match keylen {
128 => T::regs().cr().write(|w| w.set_keysize(0)),
192 => T::regs().cr().write(|w| w.set_keysize(1)),
256 => T::regs().cr().write(|w| w.set_keysize(2)),
128 => T::regs().cr().modify(|w| w.set_keysize(0)),
192 => T::regs().cr().modify(|w| w.set_keysize(1)),
256 => T::regs().cr().modify(|w| w.set_keysize(2)),
_ => panic!("Key length must be 128, 192, or 256 bits."),
}
@ -155,13 +155,13 @@ impl<'d, T: Instance> Cryp<'d, T> {
T::regs().init(0).ivlr().write_value(u32::from_be_bytes(iv_word));
iv_word.copy_from_slice(&iv[iv_idx..iv_idx + 4]);
iv_idx += 4;
if iv.len() >= 12 {
T::regs().init(0).ivrr().write_value(u32::from_be_bytes(iv_word));
if iv.len() >= 12 {
iv_word.copy_from_slice(&iv[iv_idx..iv_idx + 4]);
iv_idx += 4;
T::regs().init(1).ivlr().write_value(u32::from_be_bytes(iv_word));
}
if iv.len() >= 16 {
T::regs().init(1).ivlr().write_value(u32::from_be_bytes(iv_word));
iv_word.copy_from_slice(&iv[iv_idx..iv_idx + 4]);
T::regs().init(1).ivrr().write_value(u32::from_be_bytes(iv_word));
}
@ -206,9 +206,6 @@ impl<'d, T: Instance> Cryp<'d, T> {
self.load_context(ctx);
ctx.aad_complete = true;
if last_block {
ctx.last_block_processed = true;
}
let block_size;
if ctx.algo == Algorithm::DES {
@ -231,15 +228,19 @@ impl<'d, T: Instance> Cryp<'d, T> {
}
if !last_block {
if last_block_remainder != 0 {
panic!("Input length must be a multiple of {block_size} bytes.");
panic!("Input length must be a multiple of {} bytes.", block_size);
}
}
if (ctx.mode == Mode::ECB) || (ctx.mode == Mode::CBC) {
if last_block_remainder != 0 {
panic!("Input must be a multiple of {block_size} bytes in ECB and CBC modes. Consider padding or ciphertext stealing.");
panic!("Input must be a multiple of {} bytes in ECB and CBC modes. Consider padding or ciphertext stealing.", block_size);
}
}
if last_block {
ctx.last_block_processed = true;
}
// Load data into core, block by block.
let num_full_blocks = input.len() / block_size;
for block in 0..num_full_blocks {
@ -277,7 +278,7 @@ impl<'d, T: Instance> Cryp<'d, T> {
let mut intermediate_data: [u8; 16] = [0; 16];
let mut last_block: [u8; 16] = [0; 16];
last_block.copy_from_slice(&input[input.len() - last_block_remainder..input.len()]);
last_block[..last_block_remainder].copy_from_slice(&input[input.len() - last_block_remainder..input.len()]);
let mut index = 0;
let end_index = block_size;
// Write block in
@ -299,7 +300,8 @@ impl<'d, T: Instance> Cryp<'d, T> {
}
// Handle the last block depending on mode.
output[output.len() - last_block_remainder..output.len()]
let output_len = output.len();
output[output_len - last_block_remainder..output_len]
.copy_from_slice(&intermediate_data[0..last_block_remainder]);
if ctx.mode == Mode::GCM && ctx.dir == Direction::Encrypt {
@ -325,7 +327,7 @@ impl<'d, T: Instance> Cryp<'d, T> {
}
fn prepare_key(&self, ctx: &Context) {
if ctx.algo == Algorithm::AES {
if ctx.algo == Algorithm::AES && ctx.dir == Direction::Decrypt {
if (ctx.mode == Mode::ECB) || (ctx.mode == Mode::CBC) {
T::regs().cr().modify(|w| w.set_algomode0(7));
T::regs().cr().modify(|w| w.set_crypen(true));
@ -406,6 +408,7 @@ impl<'d, T: Instance> Cryp<'d, T> {
// Prepare key if applicable.
self.prepare_key(ctx);
T::regs().cr().write(|w| w.0 = ctx.cr);
// Enable crypto processor.
T::regs().cr().modify(|w| w.set_crypen(true));
@ -420,14 +423,14 @@ pub(crate) mod sealed {
}
}
/// RNG instance trait.
/// CRYP instance trait.
pub trait Instance: sealed::Instance + Peripheral<P = Self> + crate::rcc::RccPeripheral + 'static + Send {
/// Interrupt for this RNG instance.
/// Interrupt for this CRYP instance.
type Interrupt: interrupt::typelevel::Interrupt;
}
foreach_interrupt!(
($inst:ident, rng, CRYP, GLOBAL, $irq:ident) => {
($inst:ident, cryp, CRYP, GLOBAL, $irq:ident) => {
impl Instance for peripherals::$inst {
type Interrupt = crate::interrupt::typelevel::$irq;
}