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Corrected CCM partial block ops.

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This commit is contained in:
Caleb Garrett 2024-02-20 15:26:31 -05:00
parent 1e21b758f7
commit f64a62149e
1 changed files with 24 additions and 22 deletions

46
embassy-stm32/src/cryp/mod.rs
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@ -327,14 +327,16 @@ impl<'c, const KEY_SIZE: usize> Cipher<'c> for AesGmac<'c, KEY_SIZE> {
dir: Direction,
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;
@ -479,10 +481,10 @@ impl<'c, const KEY_SIZE: usize> Cipher<'c> for AesCcm<'c, KEY_SIZE> {
if dir == Direction::Decrypt {
p.cr().modify(|w| w.set_crypen(false));
let iv1temp = p.init(1).ivrr().read();
temp1[0] = p.csgcmccmr(0).read();
temp1[1] = p.csgcmccmr(1).read();
temp1[2] = p.csgcmccmr(2).read();
temp1[3] = p.csgcmccmr(3).read();
temp1[0] = p.csgcmccmr(0).read().swap_bytes();
temp1[1] = p.csgcmccmr(1).read().swap_bytes();
temp1[2] = p.csgcmccmr(2).read().swap_bytes();
temp1[3] = p.csgcmccmr(3).read().swap_bytes();
p.init(1).ivrr().write_value(iv1temp);
p.cr().modify(|w| w.set_algomode3(false));
p.cr().modify(|w| w.set_algomode0(6));
@ -501,27 +503,27 @@ impl<'c, const KEY_SIZE: usize> Cipher<'c> for AesCcm<'c, KEY_SIZE> {
) {
if dir == Direction::Decrypt {
//Handle special CCM partial block process.
let mut intdata_o: [u32; 4] = [0; 4];
for i in 0..intdata_o.len() {
intdata_o[i] = p.dout().read();
}
let mut temp2 = [0; 4];
temp2[0] = p.csgcmccmr(0).read();
temp2[1] = p.csgcmccmr(1).read();
temp2[2] = p.csgcmccmr(2).read();
temp2[3] = p.csgcmccmr(3).read();
p.cr().write(|w| w.set_algomode3(true));
p.cr().write(|w| w.set_algomode0(1));
temp2[0] = p.csgcmccmr(0).read().swap_bytes();
temp2[1] = p.csgcmccmr(1).read().swap_bytes();
temp2[2] = p.csgcmccmr(2).read().swap_bytes();
temp2[3] = p.csgcmccmr(3).read().swap_bytes();
p.cr().modify(|w| w.set_algomode3(true));
p.cr().modify(|w| w.set_algomode0(1));
p.cr().modify(|w| w.set_gcm_ccmph(3));
// Header phase
p.cr().modify(|w| w.set_gcm_ccmph(1));
for i in 0..AES_BLOCK_SIZE {
int_data[i] = int_data[i] & padding_mask[i];
}
let mut in_data: [u32; 4] = [0; 4];
for i in 0..in_data.len() {
let mut mask_bytes: [u8; 4] = [0; 4];
mask_bytes.copy_from_slice(&padding_mask[(i * 4)..(i * 4) + 4]);
let mask_word = u32::from_le_bytes(mask_bytes);
in_data[i] = intdata_o[i] & mask_word;
let mut int_bytes: [u8; 4] = [0; 4];
int_bytes.copy_from_slice(&int_data[(i * 4)..(i * 4) + 4]);
let int_word = u32::from_le_bytes(int_bytes);
in_data[i] = int_word;
in_data[i] = in_data[i] ^ temp1[i] ^ temp2[i];
p.din().write_value(in_data[i]);
}
}
}