SPL currently does not check uImage CRCs when loading U-Boot.
This patch adds checking the uImage CRC when SPL loads U-Boot. It does this by reusing the existing config option SPL_CRC32_SUPPORT to allow leaving out the CRC check on boards where the additional code size or boot time is a problem (adding the CRC check currently adds ~1.4 kByte to flash).
The SPL_CRC32_SUPPORT config option now gets enabled by default if SPL support for legacy images is enabled to check the CRC on all boards that don't actively take countermeasures.
Signed-off-by: Simon Goldschmidt simon.k.r.goldschmidt@gmail.com ---
Changes in v2: - added Kconfig option SPL_LEGACY_IMAGE_CRC_CHECK to enable/disable checking CRC on legacy images
common/spl/Kconfig | 21 +++++++++++++++------ common/spl/spl.c | 30 +++++++++++++++++++++++++++++- include/spl.h | 5 +++++ 3 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/common/spl/Kconfig b/common/spl/Kconfig index d0564621d4..5c6c437ef0 100644 --- a/common/spl/Kconfig +++ b/common/spl/Kconfig @@ -80,6 +80,15 @@ config SPL_LEGACY_IMAGE_SUPPORT is y. If this is not set, SPL will move on to other available boot media to find a suitable image.
+config SPL_LEGACY_IMAGE_CRC_CHECK + bool "Check CRC of Legacy images" + depends on SPL_LEGACY_IMAGE_SUPPORT + default y + select SPL_CRC32_SUPPORT + help + Enable this to check the CRC of Legacy images. While this increases + reliability, it affects both code size and boot duration. + config SPL_SYS_MALLOC_SIMPLE bool prompt "Only use malloc_simple functions in the SPL" @@ -207,13 +216,13 @@ config SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION_TYPE
config SPL_CRC32_SUPPORT bool "Support CRC32" - depends on SPL_FIT + default y if SPL_LEGACY_IMAGE_SUPPORT help - Enable this to support CRC32 in FIT images within SPL. This is a - 32-bit checksum value that can be used to verify images. This is - the least secure type of checksum, suitable for detected - accidental image corruption. For secure applications you should - consider SHA1 or SHA256. + Enable this to support CRC32 in uImages or FIT images within SPL. + This is a 32-bit checksum value that can be used to verify images. + For FIT images, this is the least secure type of checksum, suitable + for detected accidental image corruption. For secure applications you + should consider SHA1 or SHA256.
config SPL_MD5_SUPPORT bool "Support MD5" diff --git a/common/spl/spl.c b/common/spl/spl.c index 12f9359c0a..f2ea87a0ec 100644 --- a/common/spl/spl.c +++ b/common/spl/spl.c @@ -236,6 +236,14 @@ int spl_parse_image_header(struct spl_image_info *spl_image, #ifdef CONFIG_SPL_LEGACY_IMAGE_SUPPORT u32 header_size = sizeof(struct image_header);
+ if (CONFIG_IS_ENABLED(LEGACY_IMAGE_CRC_CHECK)) { + /* check uImage header CRC */ + if (!image_check_hcrc(header)) { + puts("SPL: Image header CRC check failed!\n"); + return -EINVAL; + } + } + if (spl_image->flags & SPL_COPY_PAYLOAD_ONLY) { /* * On some system (e.g. powerpc), the load-address and @@ -253,6 +261,13 @@ int spl_parse_image_header(struct spl_image_info *spl_image, spl_image->size = image_get_data_size(header) + header_size; } +#ifdef CONFIG_SPL_LEGACY_IMAGE_CRC_CHECK + /* store uImage data length and CRC to check later */ + spl_image->dcrc_data = image_get_load(header); + spl_image->dcrc_length = image_get_data_size(header); + spl_image->dcrc = image_get_dcrc(header); +#endif + spl_image->os = image_get_os(header); spl_image->name = image_get_name(header); debug("spl: payload image: %32s load addr: 0x%lx size: %d\n", @@ -424,12 +439,25 @@ static struct spl_image_loader *spl_ll_find_loader(uint boot_device) static int spl_load_image(struct spl_image_info *spl_image, struct spl_image_loader *loader) { + int ret; struct spl_boot_device bootdev;
bootdev.boot_device = loader->boot_device; bootdev.boot_device_name = NULL;
- return loader->load_image(spl_image, &bootdev); + ret = loader->load_image(spl_image, &bootdev); +#ifdef CONFIG_SPL_LEGACY_IMAGE_CRC_CHECK + if (!ret && spl_image->dcrc_length) { + /* check data crc */ + ulong dcrc = crc32_wd(0, (unsigned char *)spl_image->dcrc_data, + spl_image->dcrc_length, CHUNKSZ_CRC32); + if (dcrc != spl_image->dcrc) { + puts("SPL: Image data CRC check failed!\n"); + ret = -EINVAL; + } + } +#endif + return ret; }
/** diff --git a/include/spl.h b/include/spl.h index 9a439f468b..1b1d9ebbfb 100644 --- a/include/spl.h +++ b/include/spl.h @@ -33,6 +33,11 @@ struct spl_image_info { u32 size; u32 flags; void *arg; +#if CONFIG_IS_ENABLED(LEGACY_IMAGE_CRC_CHECK) + ulong dcrc_data; + ulong dcrc_length; + ulong dcrc; +#endif };
/*