/**************************************************************************************************
* @fn aesSignature
*
* @brief Run the AES CRC-MAC calculation over the RC image according to the
* AES Control Block parameters and update the control block accordingly.
*
* input parameters
*
* None.
*
* output parameters
*
* @param pBuf - Pointer to the KEY_BLENGTH-byte buffer to hold the signature calculated.
*
* @return TRUE or FALSE whether the AES signature could be calculated.
*/
static uint8 aesSignature(void *pBuf)
{
aesInitSig();
#if defined AES_TEST_VECS
uint8 testInput[48] = {
0x00, 0x08, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
memcpy(pageBuf+HAL_FLASH_PAGE_SIZE-48, testInput, 48);
uint8 idx = 0;
for (uint8 loop = 0; loop < 2; loop++)
{
ENCCS |= 0x01;
for (uint8 cnt = 0; cnt < KEY_BLENGTH; cnt++)
{
ENCDI = testInput[idx++];
}
while ((ENCCS & BV(3)) == 0);
}
#else
const uint8 lastPg = imgHdr.len / SBL_PAGE_LEN + SBL_PAGE_BEG - 1;
for (uint8 pg = SBL_PAGE_BEG; pg <= lastPg; pg++)
{
HalFlashRead(pg, 0, pageBuf, HAL_FLASH_PAGE_SIZE);
for (uint16 oset = 0; oset < HAL_FLASH_PAGE_SIZE; )
{
if ((pg == SBL_PAGE_BEG) && (oset == sizeof(img_hdr_t)))
{
oset += KEY_BLENGTH; // Must not include the signature bytes in the signature calculation.
}
else if ((pg == lastPg) && (oset == (HAL_FLASH_PAGE_SIZE - KEY_BLENGTH)))
{
break; // Need to change mode to CBC-MAC for the last block.
}
ENCCS |= 0x01;
for (uint8 cnt = 0; cnt < KEY_BLENGTH; cnt++)
{
ENCDI = pageBuf[oset++];
}
while ((ENCCS & BV(3)) == 0);
}
}
#endif
ENCCS = CBC | AES_ENCRYPT | 0x01; // Switch to CBC mode for the last block.
// 'while ((ENCCS & BV(3)) == 0)' was seen to hang without #pragma optimize=none.
// So proactively adding this wait after every 'ENCCS = ' which empirically seems to work.
ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP;
for (uint16 oset = (HAL_FLASH_PAGE_SIZE - KEY_BLENGTH); oset < HAL_FLASH_PAGE_SIZE; oset++)
{
ENCDI = pageBuf[oset];
}
HAL_AES_DELAY(); // Delay required for non-DMA AES as RDY bit only goes hi after read out below.
// CBC-MAC generates output on the last block.
for (uint8 cnt = 0, *pSig = (uint8 *)pBuf; cnt < KEY_BLENGTH; cnt++)
{
*pSig++ = ENCDO;
}
return TRUE;
}
/**************************************************************************************************
* @fn aesSignature
*
* @brief Run the AES CRC-MAC calculation over the image specified according to the
* AES Control Block parameters and update the control block accordingly.
*
* input parameters
*
* @param imgSel - Image select: 0 for Image-A and 1 for Image-B.
* @param aesHdr - Pointer to the aes_hdr_t info to use for the signature calculation.
*
* output parameters
*
* @param aesHdr - Pointer to the aes_hdr_t info with the signature calculated.
*
* @return TRUE or FALSE whether the AES signature calculated matches the one in the header.
*/
static uint8 aesSignature(uint8 imgSel, aes_hdr_t *aesHdr)
{
uint8 sigBuf[KEY_BLENGTH];
aesInitSig(aesHdr);
uint8 pgEnd = ImgPageBeg[imgSel] + aesHdr->spare[3] - 1;
if (imgSel == 0)
{
pgEnd += ImgPageLen[1];
}
for (uint8 pgNum = ImgPageBeg[imgSel]; pgNum <= pgEnd; )
{
BEM_NVM_GET(pgNum, pageBuf, HAL_FLASH_PAGE_SIZE);
for (uint16 oset = 0; oset < HAL_FLASH_PAGE_SIZE; )
{
if ((pgNum == ImgPageBeg[imgSel]) && (oset == sizeof(img_hdr_t)))
{
oset += KEY_BLENGTH; // Must not include the signature bytes in the signature calculation.
}
else if ((pgNum == pgEnd) && (oset == (HAL_FLASH_PAGE_SIZE - KEY_BLENGTH)))
{
break; // Need to change mode to CBC-MAC for the last block.
}
ENCCS |= 0x01;
for (uint8 cnt = 0; cnt < KEY_BLENGTH; cnt++)
{
ENCDI = pageBuf[oset++];
}
while ((ENCCS & BV(3)) == 0);
}
pgNum++;
if ((imgSel == 0) && (pgNum == ImgPageBeg[1]))
{
pgNum += ImgPageLen[1];
}
}
ENCCS = CBC | AES_ENCRYPT | 0x01; // Switch to CBC mode for the last block.
// 'while ((ENCCS & BV(3)) == 0)' was seen to hang without #pragma optimize=none.
// So proactively adding this wait after every 'ENCCS = ' which empirically seems to work.
ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP; ASM_NOP;
for (uint16 oset = (HAL_FLASH_PAGE_SIZE - KEY_BLENGTH); oset < HAL_FLASH_PAGE_SIZE; oset++)
{
ENCDI = pageBuf[oset];
}
HAL_AES_DELAY(); // Delay required for non-DMA AES as RDY bit only goes hi after read out below.
// CBC-MAC generates output on the last block.
for (uint8 cnt = 0; cnt < KEY_BLENGTH; cnt++)
{
sigBuf[cnt] = ENCDO;
}
return ((memcmp(sigBuf, aesHdr->signature, KEY_BLENGTH) == 0) ? TRUE : FALSE);
}
