From 1e21b758f795b5cc8a2331aacbc2a9a39bb7a7fb Mon Sep 17 00:00:00 2001
From: Caleb Garrett <47389035+caleb-garrett@users.noreply.github.com>
Date: Tue, 20 Feb 2024 14:27:37 -0500
Subject: [PATCH] Corrected GCM tag generation.
---
embassy-stm32/src/cryp/mod.rs | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/embassy-stm32/src/cryp/mod.rs b/embassy-stm32/src/cryp/mod.rs
index fe248def1..81446e39e 100644
--- a/embassy-stm32/src/cryp/mod.rs
+++ b/embassy-stm32/src/cryp/mod.rs
@@ -45,7 +45,7 @@ pub trait Cipher<'c> {
&self,
_p: &pac::cryp::Cryp,
_dir: Direction,
- _int_data: &[u8; AES_BLOCK_SIZE],
+ _int_data: &mut [u8; AES_BLOCK_SIZE],
_temp1: [u32; 4],
_padding_mask: [u8; 16],
) {
@@ -236,16 +236,18 @@ impl<'c, const KEY_SIZE: usize> Cipher<'c> for AesGcm<'c, KEY_SIZE> {
&self,
p: &pac::cryp::Cryp,
dir: Direction,
- int_data: &[u8; AES_BLOCK_SIZE],
+ int_data: &mut [u8; AES_BLOCK_SIZE],
_temp1: [u32; 4],
- _padding_mask: [u8; 16],
+ padding_mask: [u8; AES_BLOCK_SIZE],
) {
if dir == Direction::Encrypt {
//Handle special GCM partial block process.
p.cr().modify(|w| w.set_crypen(false));
- p.cr().write(|w| w.set_algomode3(true));
- p.cr().write(|w| w.set_algomode0(0));
- p.init(1).ivrr().write_value(2);
+ p.cr().modify(|w| w.set_algomode3(true));
+ p.cr().modify(|w| w.set_algomode0(0));
+ for i in 0..AES_BLOCK_SIZE {
+ int_data[i] = int_data[i] & padding_mask[i];
+ }
p.cr().modify(|w| w.set_crypen(true));
p.cr().modify(|w| w.set_gcm_ccmph(3));
let mut index = 0;
@@ -323,7 +325,7 @@ impl<'c, const KEY_SIZE: usize> Cipher<'c> for AesGmac<'c, KEY_SIZE> {
&self,
p: &pac::cryp::Cryp,
dir: Direction,
- int_data: &[u8; AES_BLOCK_SIZE],
+ int_data: &mut [u8; AES_BLOCK_SIZE],
_temp1: [u32; 4],
_padding_mask: [u8; 16],
) {
@@ -493,7 +495,7 @@ impl<'c, const KEY_SIZE: usize> Cipher<'c> for AesCcm<'c, KEY_SIZE> {
&self,
p: &pac::cryp::Cryp,
dir: Direction,
- int_data: &[u8; AES_BLOCK_SIZE],
+ int_data: &mut [u8; AES_BLOCK_SIZE],
temp1: [u32; 4],
padding_mask: [u8; 16],
) {
@@ -872,7 +874,7 @@ impl<'d, T: Instance> Cryp<'d, T> {
let mut mask: [u8; 16] = [0; 16];
mask[..last_block_remainder].fill(0xFF);
ctx.cipher
- .post_final_block(&T::regs(), ctx.dir, &intermediate_data, temp1, mask);
+ .post_final_block(&T::regs(), ctx.dir, &mut intermediate_data, temp1, mask);
}
ctx.payload_len += input.len() as u64;