/** * Copyright (c) 2023 Raspberry Pi (Trading) Ltd. * * SPDX-License-Identifier: BSD-3-Clause */ #include <stdio.h> #include <string.h> #include "pico/stdlib.h" #include "boot/picobin.h" #include "hardware/uart.h" #include "pico/bootrom.h" #include "pico/rand.h" #include "hardware/structs/otp.h" #include "hardware/structs/qmi.h" #include "hardware/structs/xip_ctrl.h" #include "config.h" extern void flush_reg(); volatile uint32_t systick_data[18]; // count, R0-R15,RETPSR extern void remap(); extern uint32_t gen_rand(); extern void init_key(uint8_t *rk_s, uint8_t *key); extern void gen_lut_inverse(); extern void gen_lut_sbox(); extern void gen_lut_inv_sbox(); extern int ctr_crypt_s(uint8_t*iv,uint8_t*buf,int nblk); extern uint8_t rkey_s[480]; extern uint8_t lut_a[256]; extern uint8_t lut_b[256]; extern uint32_t lut_a_map; extern uint32_t lut_b_map; extern uint32_t rstate[4]; static void init_lut_map() { int i; for(i=0;i<256;i++) lut_b[i]=gen_rand()&0xff, lut_a[i]^=lut_b[i]; lut_a_map=0; lut_b_map=0; remap(); } static __attribute__((aligned(4))) uint8_t workarea[4 * 1024]; int main() { stdio_init_all(); #if RANDOMIZE get_rand_128((rng_128_t*)rstate); // fill rstate with 128 bits of random data #else rstate[0]=1223352428; rstate[1]=1223352428; rstate[2]=0x41414141; rstate[3]=0x41414141; #endif // reset the RNG reset_block(RESETS_RESET_SHA256_BITS); unreset_block(RESETS_RESET_SHA256_BITS); rstate[0]&=0xffffff00; // bottom byte must be zero printf("Rstate at address %x\n", rstate); printf("Entered bootloader code\n"); int rc; rc = rom_load_partition_table(workarea, sizeof(workarea), false); if (rc) { printf("Partition Table Load failed %d - resetting\n", rc); reset_usb_boot(0, 0); } boot_info_t info; printf("Getting boot info\n"); rc = rom_get_boot_info(&info); uint32_t flash_update_base = 0; printf("Boot Type %x\n", info.boot_type); if (info.boot_type == BOOT_TYPE_FLASH_UPDATE) { flash_update_base = info.reboot_params[0]; printf("Flash Update Base %x\n", flash_update_base); } rc = rom_pick_ab_partition(workarea, sizeof(workarea), 0, flash_update_base); if (rc < 0) { printf("Partition Table A/B choice failed %d - resetting\n", rc); reset_usb_boot(0, 0); } uint8_t boot_partition = rc; printf("Picked A/B Boot partition %x\n", boot_partition); rc = rom_get_partition_table_info((uint32_t*)workarea, 0x8, PT_INFO_PARTITION_LOCATION_AND_FLAGS | PT_INFO_SINGLE_PARTITION | (boot_partition << 24)); uint32_t data_start_addr; uint32_t data_end_addr; if (rc != 3) { printf("No boot partition - assuming bin at start of flash\n"); data_start_addr = 0; data_end_addr = 0x70000; // must fit into 0x20000000 -> 0x20070000 } else { uint16_t first_sector_number = (((uint32_t*)workarea)[1] & PICOBIN_PARTITION_LOCATION_FIRST_SECTOR_BITS) >> PICOBIN_PARTITION_LOCATION_FIRST_SECTOR_LSB; uint16_t last_sector_number = (((uint32_t*)workarea)[1] & PICOBIN_PARTITION_LOCATION_LAST_SECTOR_BITS) >> PICOBIN_PARTITION_LOCATION_LAST_SECTOR_LSB; data_start_addr = first_sector_number * 0x1000; data_end_addr = (last_sector_number + 1) * 0x1000; printf("Partition Start %x, End %x\n", data_start_addr, data_end_addr); } printf("Decrypting the chosen image\n"); uint32_t first_mb_start = 0; uint32_t first_mb_end = 0; uint32_t last_mb_start = 0; for (uint16_t i=0; i <= 0x1000; i += 4) { if (*(uint32_t*)(XIP_BASE + data_start_addr + i) == 0xffffded3) { printf("Found first block start\n"); first_mb_start = i; } if (*(uint32_t*)(XIP_BASE + data_start_addr + i) == 0xab123579) { printf("Found first block end\n"); first_mb_end = i + 4; last_mb_start = *(uint32_t*)(XIP_BASE + data_start_addr + i-4) + first_mb_start; break; } } if (*(uint32_t*)(XIP_BASE + data_start_addr + last_mb_start) == 0xffffded3) { printf("Found last block start where expected\n"); } else { printf("Did not find last block where expected\n"); last_mb_start = 0; } if (first_mb_end == 0 || last_mb_start == 0) { printf("Couldn't find encrypted image %x %x - resetting\n", first_mb_end, last_mb_start); reset_usb_boot(0, 0); } printf("Encrypted from %x to %x\n", first_mb_end, last_mb_start); if (data_start_addr + last_mb_start > data_end_addr) { // todo - harden this check printf("ERROR: Encrypted binary is too big for it's partition - resetting\n"); reset_usb_boot(0, 0); } printf("OTP Valid Keys %x\n", otp_hw->key_valid); printf("Unlocking\n"); for (int i=0; i<4; i++) { uint32_t key_i = ((i*2+1) << 24) | ((i*2+1) << 16) | (i*2 << 8) | i*2; otp_hw->crt_key_w[i] = key_i; } uint8_t iv[16]; data_start_addr += first_mb_end; memcpy(iv, (void*)(XIP_BASE + data_start_addr), sizeof(iv)); data_start_addr += 16; uint32_t data_size = last_mb_start - (first_mb_end + 16); printf("Data start %x, size %x\n", data_start_addr, data_size); if (SRAM_BASE + data_size > 0x20070000) { // todo - harden this check printf("ERROR: Encrypted binary is too big, and will overwrite this bootloader - resetting\n"); reset_usb_boot(0, 0); } memcpy((void*)SRAM_BASE, (void*)(XIP_BASE + data_start_addr), data_size); printf("Pre decryption image begins with\n"); for (int i=0; i < 4; i++) printf("%08x\n", *(uint32_t*)(SRAM_BASE + i*4)); flush_reg(); #if !SBOX_VIA_INV gen_lut_sbox(); #else gen_lut_inverse(); #endif init_lut_map(); // Read key directly from OTP - guarded reads will throw a bus fault if there are any errors uint16_t* otp_data = (uint16_t*)OTP_DATA_GUARDED_BASE; init_key(rkey_s, (uint8_t*)&(otp_data[(OTP_CMD_ROW_BITS & 0x780)])); otp_hw->sw_lock[30] = 0xf; flush_reg(); ctr_crypt_s(iv, (void*)SRAM_BASE, data_size/16); flush_reg(); printf("Post decryption image begins with\n"); for (int i=0; i < 4; i++) printf("%08x\n", *(uint32_t*)(SRAM_BASE + i*4)); printf("Chaining into %x, size %x\n", SRAM_BASE, data_size); stdio_deinit_all(); rc = rom_chain_image( workarea, sizeof(workarea), SRAM_BASE, data_size ); stdio_init_all(); printf("Shouldn't return from ROM call %d\n", rc); reset_usb_boot(0, 0); }

This firmware image was imported from the pico-examples repository. 


Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
   disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
   disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.