On Wed, Jun 26, 2019 at 06:58:51AM +0200, Rouven Czerwinski wrote:
> Add piggydata verification before the ARM uncompress function.
> This calculates the sha256sum of the compressed barebox binary and only
> continues if the builtin sha256sum matches the calculated sha256sum.
>
> Signed-off-by: Rouven Czerwinski <r.czerwinski@xxxxxxxxxxxxxx>
> ---
> arch/arm/cpu/uncompress.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/cpu/uncompress.c b/arch/arm/cpu/uncompress.c
> index e527165..ce5f2c1 100644
> --- a/arch/arm/cpu/uncompress.c
> +++ b/arch/arm/cpu/uncompress.c
> @@ -42,14 +42,18 @@ unsigned long free_mem_end_ptr;
> extern unsigned char input_data[];
> extern unsigned char input_data_end[];
>
> +extern unsigned char sha_sum[];
> +extern unsigned char sha_sum_end[];
> +
> void __noreturn barebox_multi_pbl_start(unsigned long membase,
> unsigned long memsize, void *boarddata)
> {
> - uint32_t pg_len, uncompressed_len;
> + uint32_t pg_len, uncompressed_len, pbl_hash_len;
> void __noreturn (*barebox)(unsigned long, unsigned long, void *);
> unsigned long endmem = membase + memsize;
> unsigned long barebox_base;
> void *pg_start, *pg_end;
> + void *pbl_hash_start, *pbl_hash_end;
> unsigned long pc = get_pc();
>
> pg_start = input_data + global_variable_offset();
> @@ -92,6 +96,18 @@ void __noreturn barebox_multi_pbl_start(unsigned long membase,
> pr_debug("uncompressing barebox binary at 0x%p (size 0x%08x) to 0x%08lx (uncompressed size: 0x%08x)\n",
> pg_start, pg_len, barebox_base, uncompressed_len);
>
> + if (IS_ENABLED(CONFIG_PBL_VERIFY_PIGGY)) {
> + pbl_hash_start = sha_sum + global_variable_offset();
> + pbl_hash_end = sha_sum_end + global_variable_offset();
> + pbl_hash_len = pbl_hash_end - pbl_hash_start;
> + if (pbl_barebox_verify(pg_start, pg_len, pbl_hash_start,
> + pbl_hash_len) != 0) {
> + putc_ll('!');
> + pr_err("hash mismatch, refusing to decompress");
> + panic("hash mismatch, refusing to decompress");
Isn't printing the string in panic() enough?
Sascha
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