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Code Issues Releases Wiki Activity

Check if firmware has privileges. (#369)

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Only drop privileges if firmware is running with privileges.
Don't change the bootloader if running without privileges.
This commit is contained in:
Jochen Hoenicke 2018-06-21 14:28:39 +02:00 committed by Pavol Rusnak
parent 027e64d21a
commit 0ddf443346
3 changed files with 19 additions and 3 deletions
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6
firmware/bl_check.c
View File

@ -53,6 +53,10 @@ void check_bootloader(void)
shutdown();
}
if (is_mode_unprivileged()) {
return;
}
if (r == 32 && 0 == memcmp(hash, bl_hash, 32)) {
// all OK -> done
return;
@ -62,6 +66,8 @@ void check_bootloader(void)
// ATTEMPTING TO OVERWRITE BOOTLOADER WITH UNSIGNED FIRMWARE MAY BRICK
// YOUR DEVICE.
layoutDialog(&bmp_icon_warning, NULL, NULL, NULL, "Overwriting bootloader", NULL, NULL, "DON'T UNPLUG", "YOUR TREZOR", NULL);
// unlock sectors
memory_write_unlock();

3
firmware/trezor.c
View File

@ -96,12 +96,15 @@ int main(void)
__stack_chk_guard = random32(); // this supports compiler provided unpredictable stack protection checks
#endif
if (!is_mode_unprivileged()) {
timer_init();
#ifdef APPVER
// enable MPU (Memory Protection Unit)
mpu_config();
#endif
}
#if DEBUG_LINK
oledSetDebugLink(1);

7
util.h
View File

@ -79,6 +79,13 @@ static inline void set_mode_unprivileged(void)
// http://infocenter.arm.com/help/topic/com.arm.doc.dui0552a/CHDBIBGJ.html
__asm__ volatile("msr control, %0" :: "r" (0x1));
}
static inline bool is_mode_unprivileged(void)
{
uint32_t r0;
__asm__ volatile("mrs %0, control" : "=r" (r0));
return r0 & 1;
}
#endif
#endif