Git-Mirrors/tillitis-key
1
0
Fork 0
mirror of https://github.com/tillitis/tillitis-key1.git synced 2024-12-20 13:24:24 -05:00
Code Issues Packages Projects Releases Wiki Activity

fw: enable addr & data scrambling; fill RAM with random data

Browse Source 
Use a rnd_word() func

Signed-off-by: Daniel Lublin <daniel@lublin.se>
This commit is contained in:
Daniel Lublin 2023-03-09 08:47:53 +01:00
parent 4afdc1cd1f
commit 957df5e6b4
No known key found for this signature in database
GPG Key ID: 75BD0FEB8D3E7830
1 changed files with 28 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
hw/application_fpga/fw/tk1/main.c
View File

@ -28,6 +28,8 @@ static volatile uint32_t *timer = (volatile uint32_t *)TK1_MMIO_TIMER_
static volatile uint32_t *timer_prescaler = (volatile uint32_t *)TK1_MMIO_TIMER_PRESCALER;
static volatile uint32_t *timer_status = (volatile uint32_t *)TK1_MMIO_TIMER_STATUS;
static volatile uint32_t *timer_ctrl = (volatile uint32_t *)TK1_MMIO_TIMER_CTRL;
static volatile uint32_t *ram_aslr = (volatile uint32_t *)TK1_MMIO_TK1_RAM_ASLR;
static volatile uint32_t *ram_scramble = (volatile uint32_t *)TK1_MMIO_TK1_RAM_SCRAMBLE;
// clang-format on
struct namever {
@ -90,6 +92,13 @@ static void print_digest(uint8_t *md)
htif_lf();
}
uint32_t rnd_word()
{
while ((*trng_status & (1 << TK1_MMIO_TRNG_STATUS_READY_BIT)) == 0) {
}
return *trng_entropy;
}
// CDI = blake2s(uds, blake2s(app), uss)
static void compute_cdi(uint8_t digest[32], uint8_t use_uss, uint8_t uss[32])
{
@ -98,9 +107,7 @@ static void compute_cdi(uint8_t digest[32], uint8_t use_uss, uint8_t uss[32])
// Prepare to sleep a random number of cycles before reading out UDS
*timer_prescaler = 1;
while ((*trng_status & (1 << TK1_MMIO_TRNG_STATUS_READY_BIT)) == 0) {
}
uint32_t rnd = *trng_entropy;
uint32_t rnd = rnd_word();
// Up to 65536 cycles
rnd &= 0xffff;
*timer = (rnd == 0 ? 1 : rnd);
@ -143,6 +150,24 @@ enum state {
int main()
{
// Set RAM address and data scrambling values
*ram_aslr = rnd_word();
*ram_scramble = rnd_word();
// Fill RAM with random data (FW does not use RAM, has its stack in
// FW_RAM)
uint32_t *loadaddrw = (uint32_t *)(TK1_RAM_BASE);
uint32_t rnd = rnd_word();
uint32_t rnd_incr = rnd_word();
for (uint32_t w = 0; w < TK1_RAM_SIZE / 4; w++) {
loadaddrw[w] = rnd;
rnd += rnd_incr;
}
// Set new scrambling values, for all use of RAM by app
*ram_aslr = rnd_word();
*ram_scramble = rnd_word();
struct namever namever = get_hw_version(*name0, *name1, *ver);
struct frame_header hdr; // Used in both directions
uint8_t cmd[CMDLEN_MAXBYTES];