u-boot/boot/image-pre-load.c
Steven Lawrance 05b0f241f2 boot: image-pre-load: Check environment for location of signature info
Setting an alternative signature info node in "pre_load_sig_info_path"
allows verification of an image using the bootm pre-load mechanism with
a different key, e.g.: setenv pre_load_sig_info_path "/alt/sig" ; bootm
preload [addr]

Signed-off-by: Steven Lawrance <steven.lawrance@softathome.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2022-10-11 15:40:48 -04:00

373 lines
8 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2021 Philippe Reynes <philippe.reynes@softathome.com>
*/
#include <common.h>
#include <asm/global_data.h>
DECLARE_GLOBAL_DATA_PTR;
#include <image.h>
#include <mapmem.h>
#include <u-boot/sha256.h>
/*
* Offset of the image
*
* This value is used to skip the header before really launching the image
*/
ulong image_load_offset;
/*
* This function gathers information about the signature check
* that could be done before launching the image.
*
* return:
* < 0 => an error has occurred
* 0 => OK
* 1 => no setup
*/
static int image_pre_load_sig_setup(struct image_sig_info *info)
{
const void *algo_name, *padding_name, *key, *mandatory;
const u32 *sig_size;
int key_len;
int node, ret = 0;
char *sig_info_path = NULL;
if (!info) {
log_err("ERROR: info is NULL for image pre-load sig check\n");
ret = -EINVAL;
goto out;
}
memset(info, 0, sizeof(*info));
sig_info_path = env_get("pre_load_sig_info_path");
if (!sig_info_path)
sig_info_path = IMAGE_PRE_LOAD_PATH;
node = fdt_path_offset(gd_fdt_blob(), sig_info_path);
if (node < 0) {
log_info("INFO: no info for image pre-load sig check\n");
ret = 1;
goto out;
}
algo_name = fdt_getprop(gd_fdt_blob(), node,
IMAGE_PRE_LOAD_PROP_ALGO_NAME, NULL);
if (!algo_name) {
printf("ERROR: no algo_name for image pre-load sig check\n");
ret = -EINVAL;
goto out;
}
padding_name = fdt_getprop(gd_fdt_blob(), node,
IMAGE_PRE_LOAD_PROP_PADDING_NAME, NULL);
if (!padding_name) {
log_info("INFO: no padding_name provided, so using pkcs-1.5\n");
padding_name = "pkcs-1.5";
}
sig_size = fdt_getprop(gd_fdt_blob(), node,
IMAGE_PRE_LOAD_PROP_SIG_SIZE, NULL);
if (!sig_size) {
log_err("ERROR: no signature-size for image pre-load sig check\n");
ret = -EINVAL;
goto out;
}
key = fdt_getprop(gd_fdt_blob(), node,
IMAGE_PRE_LOAD_PROP_PUBLIC_KEY, &key_len);
if (!key) {
log_err("ERROR: no key for image pre-load sig check\n");
ret = -EINVAL;
goto out;
}
info->algo_name = (char *)algo_name;
info->padding_name = (char *)padding_name;
info->key = (uint8_t *)key;
info->key_len = key_len;
info->sig_size = fdt32_to_cpu(*sig_size);
mandatory = fdt_getprop(gd_fdt_blob(), node,
IMAGE_PRE_LOAD_PROP_MANDATORY, NULL);
if (mandatory && !strcmp((char *)mandatory, "yes"))
info->mandatory = 1;
/* Compute signature information */
info->sig_info.name = info->algo_name;
info->sig_info.padding = image_get_padding_algo(info->padding_name);
info->sig_info.checksum = image_get_checksum_algo(info->sig_info.name);
info->sig_info.crypto = image_get_crypto_algo(info->sig_info.name);
info->sig_info.key = info->key;
info->sig_info.keylen = info->key_len;
out:
return ret;
}
static int image_pre_load_sig_get_magic(ulong addr, u32 *magic)
{
struct sig_header_s *sig_header;
int ret = 0;
sig_header = (struct sig_header_s *)map_sysmem(addr, SIG_HEADER_LEN);
if (!sig_header) {
log_err("ERROR: can't map first header\n");
ret = -EFAULT;
goto out;
}
*magic = fdt32_to_cpu(sig_header->magic);
unmap_sysmem(sig_header);
out:
return ret;
}
static int image_pre_load_sig_get_header_size(ulong addr, u32 *header_size)
{
struct sig_header_s *sig_header;
int ret = 0;
sig_header = (struct sig_header_s *)map_sysmem(addr, SIG_HEADER_LEN);
if (!sig_header) {
log_err("ERROR: can't map first header\n");
ret = -EFAULT;
goto out;
}
*header_size = fdt32_to_cpu(sig_header->header_size);
unmap_sysmem(sig_header);
out:
return ret;
}
/*
* return:
* < 0 => no magic and magic mandatory (or error when reading magic)
* 0 => magic found
* 1 => magic NOT found
*/
static int image_pre_load_sig_check_magic(struct image_sig_info *info, ulong addr)
{
u32 magic;
int ret = 1;
ret = image_pre_load_sig_get_magic(addr, &magic);
if (ret < 0)
goto out;
if (magic != IMAGE_PRE_LOAD_SIG_MAGIC) {
if (info->mandatory) {
log_err("ERROR: signature is mandatory\n");
ret = -EINVAL;
goto out;
}
ret = 1;
goto out;
}
ret = 0; /* magic found */
out:
return ret;
}
static int image_pre_load_sig_check_header_sig(struct image_sig_info *info, ulong addr)
{
void *header;
struct image_region reg;
u32 sig_len;
u8 *sig;
int ret = 0;
/* Only map header of the header and its signature */
header = (void *)map_sysmem(addr, SIG_HEADER_LEN + info->sig_size);
if (!header) {
log_err("ERROR: can't map header\n");
ret = -EFAULT;
goto out;
}
reg.data = header;
reg.size = SIG_HEADER_LEN;
sig = (uint8_t *)header + SIG_HEADER_LEN;
sig_len = info->sig_size;
ret = info->sig_info.crypto->verify(&info->sig_info, &reg, 1, sig, sig_len);
if (ret) {
log_err("ERROR: header signature check has failed (err=%d)\n", ret);
ret = -EINVAL;
goto out_unmap;
}
out_unmap:
unmap_sysmem(header);
out:
return ret;
}
static int image_pre_load_sig_check_img_sig_sha256(struct image_sig_info *info, ulong addr)
{
struct sig_header_s *sig_header;
u32 header_size, offset_img_sig;
void *header;
u8 sha256_img_sig[SHA256_SUM_LEN];
int ret = 0;
sig_header = (struct sig_header_s *)map_sysmem(addr, SIG_HEADER_LEN);
if (!sig_header) {
log_err("ERROR: can't map first header\n");
ret = -EFAULT;
goto out;
}
header_size = fdt32_to_cpu(sig_header->header_size);
offset_img_sig = fdt32_to_cpu(sig_header->offset_img_sig);
header = (void *)map_sysmem(addr, header_size);
if (!header) {
log_err("ERROR: can't map header\n");
ret = -EFAULT;
goto out_sig_header;
}
sha256_csum_wd(header + offset_img_sig, info->sig_size,
sha256_img_sig, CHUNKSZ_SHA256);
ret = memcmp(sig_header->sha256_img_sig, sha256_img_sig, SHA256_SUM_LEN);
if (ret) {
log_err("ERROR: sha256 of image signature is invalid\n");
ret = -EFAULT;
goto out_header;
}
out_header:
unmap_sysmem(header);
out_sig_header:
unmap_sysmem(sig_header);
out:
return ret;
}
static int image_pre_load_sig_check_img_sig(struct image_sig_info *info, ulong addr)
{
struct sig_header_s *sig_header;
u32 header_size, image_size, offset_img_sig;
void *image;
struct image_region reg;
u32 sig_len;
u8 *sig;
int ret = 0;
sig_header = (struct sig_header_s *)map_sysmem(addr, SIG_HEADER_LEN);
if (!sig_header) {
log_err("ERROR: can't map first header\n");
ret = -EFAULT;
goto out;
}
header_size = fdt32_to_cpu(sig_header->header_size);
image_size = fdt32_to_cpu(sig_header->image_size);
offset_img_sig = fdt32_to_cpu(sig_header->offset_img_sig);
unmap_sysmem(sig_header);
image = (void *)map_sysmem(addr, header_size + image_size);
if (!image) {
log_err("ERROR: can't map full image\n");
ret = -EFAULT;
goto out;
}
reg.data = image + header_size;
reg.size = image_size;
sig = (uint8_t *)image + offset_img_sig;
sig_len = info->sig_size;
ret = info->sig_info.crypto->verify(&info->sig_info, &reg, 1, sig, sig_len);
if (ret) {
log_err("ERROR: signature check has failed (err=%d)\n", ret);
ret = -EINVAL;
goto out_unmap_image;
}
log_info("INFO: signature check has succeed\n");
out_unmap_image:
unmap_sysmem(image);
out:
return ret;
}
int image_pre_load_sig(ulong addr)
{
struct image_sig_info info;
int ret;
ret = image_pre_load_sig_setup(&info);
if (ret < 0)
goto out;
if (ret > 0) {
ret = 0;
goto out;
}
ret = image_pre_load_sig_check_magic(&info, addr);
if (ret < 0)
goto out;
if (ret > 0) {
ret = 0;
goto out;
}
/* Check the signature of the signature header */
ret = image_pre_load_sig_check_header_sig(&info, addr);
if (ret < 0)
goto out;
/* Check sha256 of the image signature */
ret = image_pre_load_sig_check_img_sig_sha256(&info, addr);
if (ret < 0)
goto out;
/* Check the image signature */
ret = image_pre_load_sig_check_img_sig(&info, addr);
if (!ret) {
u32 header_size;
ret = image_pre_load_sig_get_header_size(addr, &header_size);
if (ret) {
log_err("%s: can't get header size\n", __func__);
ret = -EINVAL;
goto out;
}
image_load_offset += header_size;
}
out:
return ret;
}
int image_pre_load(ulong addr)
{
int ret = 0;
image_load_offset = 0;
if (CONFIG_IS_ENABLED(IMAGE_PRE_LOAD_SIG))
ret = image_pre_load_sig(addr);
return ret;
}