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stm32/mboot: Verify CRC32 of fsload DFU files before writing.

This commit is contained in:
Andrew Leech 2021-06-17 12:55:18 +10:00 committed by Damien George
parent bc856a1e29
commit bb0ca00b77
2 changed files with 13 additions and 1 deletions
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13
ports/stm32/mboot/fsload.c
View File

@ -27,6 +27,7 @@
#include <string.h>
#include "py/mphal.h"
#include "lib/uzlib/tinf.h"
#include "mboot.h"
#include "pack.h"
#include "vfs.h"
@ -74,6 +75,7 @@ static inline int input_stream_read(size_t len, uint8_t *buf) {
static int fsload_program_file(bool write_to_flash) {
// Parse DFU
uint32_t crc = 0xffffffff;
uint8_t buf[512];
size_t file_offset;
@ -83,6 +85,7 @@ static int fsload_program_file(bool write_to_flash) {
return -MBOOT_ERRNO_DFU_READ_ERROR;
}
file_offset = 11;
crc = uzlib_crc32(buf, 11, crc);
// Validate header, version 1
if (memcmp(buf, "DfuSe\x01", 6) != 0) {
@ -103,6 +106,7 @@ static int fsload_program_file(bool write_to_flash) {
return -MBOOT_ERRNO_DFU_READ_ERROR;
}
file_offset += 274;
crc = uzlib_crc32(buf, 274, crc);
// Validate target header, with alt being 0
if (memcmp(buf, "Target\x00", 7) != 0) {
@ -123,6 +127,7 @@ static int fsload_program_file(bool write_to_flash) {
return -MBOOT_ERRNO_DFU_READ_ERROR;
}
file_offset += 8;
crc = uzlib_crc32(buf, 8, crc);
// Get element destination address and size
uint32_t elem_addr = get_le32(buf);
@ -151,6 +156,7 @@ static int fsload_program_file(bool write_to_flash) {
if (res != l) {
return -MBOOT_ERRNO_DFU_READ_ERROR;
}
crc = uzlib_crc32(buf, l, crc);
res = do_write(elem_addr, buf, l, !write_to_flash);
if (res != 0) {
return res;
@ -176,7 +182,12 @@ static int fsload_program_file(bool write_to_flash) {
return -MBOOT_ERRNO_DFU_READ_ERROR;
}
// TODO validate CRC32
// The final 4 bytes of the file are the expected CRC32, so including these
// bytes in the CRC calculation should yield a final CRC32 of 0.
crc = uzlib_crc32(buf, 16, crc);
if (crc != 0) {
return -MBOOT_ERRNO_DFU_INVALID_CRC;
}
return 0;
}

1
ports/stm32/mboot/mboot.h
View File

@ -56,6 +56,7 @@ enum {
MBOOT_ERRNO_DFU_INVALID_SIZE,
MBOOT_ERRNO_DFU_TOO_MANY_TARGETS,
MBOOT_ERRNO_DFU_READ_ERROR,
MBOOT_ERRNO_DFU_INVALID_CRC,
MBOOT_ERRNO_FSLOAD_NO_FSLOAD = 220,
MBOOT_ERRNO_FSLOAD_NO_MOUNT,