[U-Boot] [PATCH] RFC: Secure boot to U-Boot proper from SPL
Teddy Reed
teddy.reed at gmail.com
Mon May 9 03:13:50 CEST 2016
On Sun, May 1, 2016 at 11:12 AM, Teddy Reed <teddy.reed at gmail.com> wrote:
> I've been using the following patch for my configurations, please excuse the top-posting. I think the only difference is enabling the uclass mod_exp driver to initialize without needing relocation.
>
If no one has any additional notes / requirements for enablement in
SPL I can send my tiny bit of configuration changes as a patch.
I've tested the DM flag change for the RSA mod_exp driver class for
both relocated (u-boot) and non-relocated (SPL) builds and found no
issues. It would be awesome to get another set of eyes on the Makefile
feature reorganization as I don't want this to include unneeded code
into SPLs. :)
> ---
>
> This allows a board to configure verified boot within the SPL using
> a FIT or FIT with external data. It also allows the SPL to perform
> signature verification without needing relocation.
>
> The board configuration will need to add the following feature defines:
> CONFIG_SPL_CRYPTO_SUPPORT
> CONFIG_SPL_HASH_SUPPORT
> CONFIG_SPL_SHA256
>
> In this example, SHA256 is the selected hashing algorithm.
>
> And the following booleans:
> CONFIG_SPL=y
> CONFIG_SPL_DM=y
> CONFIG_SPL_LOAD_FIT=y
> CONFIG_SPL_FIT=y
> CONFIG_SPL_OF_CONTROL=y
> CONFIG_SPL_OF_LIBFDT=y
> CONFIG_SPL_FIT_SIGNATURE=y
>
> Signed-off-by: Teddy Reed <teddy.reed at gmail.com>
> ---
> Kconfig | 11 +++++++++++
> common/Makefile | 1 +
> drivers/Makefile | 1 +
> drivers/crypto/rsa_mod_exp/mod_exp_sw.c | 1 +
> lib/Makefile | 9 +++++----
> lib/rsa/Kconfig | 3 +++
> lib/rsa/Makefile | 2 +-
> 7 files changed, 23 insertions(+), 5 deletions(-)
>
> diff --git a/Kconfig b/Kconfig
> index f53759a..e73ad03 100644
> --- a/Kconfig
> +++ b/Kconfig
> @@ -183,6 +183,11 @@ config FIT
> verified boot (secure boot using RSA). This option enables that
> feature.
>
> +config SPL_FIT
> + bool "Support Flattened Image Tree within SPL"
> + depends on FIT
> + depends on SPL
> +
> config FIT_VERBOSE
> bool "Display verbose messages on FIT boot"
> depends on FIT
> @@ -205,6 +210,12 @@ config FIT_SIGNATURE
> format support in this case, enable it using
> CONFIG_IMAGE_FORMAT_LEGACY.
>
> +config SPL_FIT_SIGNATURE
> + bool "Enable signature verification of FIT firmware within SPL"
> + depends on SPL_FIT
> + depends on SPL_DM
> + select SPL_RSA
> +
> config FIT_BEST_MATCH
> bool "Select the best match for the kernel device tree"
> depends on FIT
> diff --git a/common/Makefile b/common/Makefile
> index b23f312..271f633 100644
> --- a/common/Makefile
> +++ b/common/Makefile
> @@ -91,6 +91,7 @@ obj-$(CONFIG_USB_KEYBOARD) += usb_kbd.o
> endif # !CONFIG_SPL_BUILD
>
> ifdef CONFIG_SPL_BUILD
> +obj-$(CONFIG_SPL_HASH_SUPPORT) += hash.o
> obj-$(CONFIG_ENV_IS_IN_FLASH) += env_flash.o
> obj-$(CONFIG_SPL_YMODEM_SUPPORT) += xyzModem.o
> obj-$(CONFIG_SPL_NET_SUPPORT) += miiphyutil.o
> diff --git a/drivers/Makefile b/drivers/Makefile
> index 6900097..456492f 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_$(SPL_)RAM) += ram/
>
> ifdef CONFIG_SPL_BUILD
>
> +obj-$(CONFIG_SPL_CRYPTO_SUPPORT) += crypto/
> obj-$(CONFIG_SPL_I2C_SUPPORT) += i2c/
> obj-$(CONFIG_SPL_GPIO_SUPPORT) += gpio/
> obj-$(CONFIG_SPL_MMC_SUPPORT) += mmc/
> diff --git a/drivers/crypto/rsa_mod_exp/mod_exp_sw.c b/drivers/crypto/rsa_mod_exp/mod_exp_sw.c
> index dc6c064..56d7e89 100644
> --- a/drivers/crypto/rsa_mod_exp/mod_exp_sw.c
> +++ b/drivers/crypto/rsa_mod_exp/mod_exp_sw.c
> @@ -32,6 +32,7 @@ U_BOOT_DRIVER(mod_exp_sw) = {
> .name = "mod_exp_sw",
> .id = UCLASS_MOD_EXP,
> .ops = &mod_exp_ops_sw,
> + .flags = DM_FLAG_PRE_RELOC,
> };
>
> U_BOOT_DEVICE(mod_exp_sw) = {
> diff --git a/lib/Makefile b/lib/Makefile
> index 02dfa29..5c83e32 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -9,7 +9,6 @@ ifndef CONFIG_SPL_BUILD
>
> obj-$(CONFIG_EFI) += efi/
> obj-$(CONFIG_EFI_LOADER) += efi_loader/
> -obj-$(CONFIG_RSA) += rsa/
> obj-$(CONFIG_LZMA) += lzma/
> obj-$(CONFIG_LZO) += lzo/
> obj-$(CONFIG_ZLIB) += zlib/
> @@ -25,8 +24,6 @@ obj-y += crc8.o
> obj-y += crc16.o
> obj-$(CONFIG_ERRNO_STR) += errno_str.o
> obj-$(CONFIG_FIT) += fdtdec_common.o
> -obj-$(CONFIG_$(SPL_)OF_CONTROL) += fdtdec_common.o
> -obj-$(CONFIG_$(SPL_)OF_CONTROL) += fdtdec.o
> obj-$(CONFIG_TEST_FDTDEC) += fdtdec_test.o
> obj-$(CONFIG_GZIP) += gunzip.o
> obj-$(CONFIG_GZIP_COMPRESSED) += gzip.o
> @@ -41,7 +38,6 @@ obj-y += qsort.o
> obj-y += rc4.o
> obj-$(CONFIG_SHA1) += sha1.o
> obj-$(CONFIG_SUPPORT_EMMC_RPMB) += sha256.o
> -obj-$(CONFIG_SHA256) += sha256.o
> obj-y += strmhz.o
> obj-$(CONFIG_TPM) += tpm.o
> obj-$(CONFIG_RBTREE) += rbtree.o
> @@ -49,6 +45,11 @@ obj-$(CONFIG_BITREVERSE) += bitrev.o
> obj-y += list_sort.o
> endif
>
> +obj-$(CONFIG_$(SPL_)OF_CONTROL) += fdtdec_common.o
> +obj-$(CONFIG_$(SPL_)OF_CONTROL) += fdtdec.o
> +obj-$(CONFIG_$(SPL_)RSA) += rsa/
> +obj-$(CONFIG_$(SPL_)SHA256) += sha256.o
> +
> obj-$(CONFIG_$(SPL_)OF_LIBFDT) += libfdt/
> ifdef CONFIG_SPL_OF_CONTROL
> obj-$(CONFIG_OF_LIBFDT) += libfdt/
> diff --git a/lib/rsa/Kconfig b/lib/rsa/Kconfig
> index 86df0a0..ec80e43 100644
> --- a/lib/rsa/Kconfig
> +++ b/lib/rsa/Kconfig
> @@ -13,6 +13,9 @@ config RSA
> option. The software based modular exponentiation is built into
> mkimage irrespective of this option.
>
> +config SPL_RSA
> + bool "Use RSA Library within SPL"
> +
> if RSA
> config RSA_SOFTWARE_EXP
> bool "Enable driver for RSA Modular Exponentiation in software"
> diff --git a/lib/rsa/Makefile b/lib/rsa/Makefile
> index 6867e50..4b2c1ba 100644
> --- a/lib/rsa/Makefile
> +++ b/lib/rsa/Makefile
> @@ -7,5 +7,5 @@
> # SPDX-License-Identifier: GPL-2.0+
> #
>
> -obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o
> +obj-$(CONFIG_$(SPL_)FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o
> obj-$(CONFIG_RSA_SOFTWARE_EXP) += rsa-mod-exp.o
> --
> 1.9.1
>
>
>
> On Sun, 1 May 2016 11:45:22 -0600
> Simon Glass <sjg at chromium.org> wrote:
>
>> For those that have asked me about this, I have dug into the past and cannot
>> find my experiment. In the end I managed to reduce U-Boot proper down to
>> about 100KB of code (by dropping CONFIG_CMD and removing video and USB
>> drivers) and this was small enough to fit in SRAM. So SPL was not needed.
>>
>> That said, my experiment drove a lot of the FIT and image refactoring and
>> I think it is actually pretty easy now to enable the full FIT implementation
>> in SPL, if your SoC limitations allow it.
>>
>> In the case of Chrome OS, both U-Boot SPL and U-Boot proper are in read-only
>> memory so there is no need for this. But even then it is useful to be able
>> to have the smallest amount of non-updateable software, so quite a bit of
>> work was done (for pit/pi) to support loading a read-write 'U-Boot proper'
>> from SPL.
>>
>> So I think it would be useful to support loading and verifying FIT images
>> with public key encryption in U-Boot, and fairly straightforward.
>>
>> To help things along, here is a starting point for firefly-rk3288 (Thumb 2).
>> This board already uses device tree in SPL (perhaps bravely given the SoC
>> size limitations) so the additional code would be a few KB larger for
>> platforms that don't.
>>
>> For firefly the code size increases from 26KB to 40 KB. There is a fair bit
>> of opportunity to reduce this if needed, for example by cutting out strings.
>>
>> Please reply on this thread if you plan to pick this up and prepare a series
>> to enable this in U-Boot, to reduce duplicated work.
>> Signed-off-by: Simon Glass <sjg at chromium.org>
>> ---
>>
>> Kconfig | 8 ++++++++
>> common/Makefile | 3 ++-
>> common/image-fit.c | 2 +-
>> common/spl/spl.c | 1 +
>> configs/firefly-rk3288_defconfig | 5 +++++
>> drivers/Makefile | 1 +
>> include/configs/rk3288_common.h | 2 ++
>> lib/Makefile | 3 ++-
>> lib/rsa/rsa-verify.c | 5 ++++-
>> 9 files changed, 26 insertions(+), 4 deletions(-)
>>
>> diff --git a/Kconfig b/Kconfig
>> index f53759a..4ffcc76 100644
>> --- a/Kconfig
>> +++ b/Kconfig
>> @@ -183,6 +183,10 @@ config FIT
>> verified boot (secure boot using RSA). This option enables that
>> feature.
>>
>> +config SPL_FIT
>> + bool "Support Flattened Image Tree in SPL"
>> + depends on FIT
>> +
>> config FIT_VERBOSE
>> bool "Display verbose messages on FIT boot"
>> depends on FIT
>> @@ -205,6 +209,10 @@ config FIT_SIGNATURE
>> format support in this case, enable it using
>> CONFIG_IMAGE_FORMAT_LEGACY.
>>
>> +config SPL_FIT_SIGNATURE
>> + bool "Enable signature verification of FIT uImages in SPL"
>> + depends on FIT_SIGNATURE
>> +
>> config FIT_BEST_MATCH
>> bool "Select the best match for the kernel device tree"
>> depends on FIT
>> diff --git a/common/Makefile b/common/Makefile
>> index b23f312..647a4ed 100644
>> --- a/common/Makefile
>> +++ b/common/Makefile
>> @@ -10,7 +10,6 @@ ifndef CONFIG_SPL_BUILD
>> obj-y += init/
>> obj-y += main.o
>> obj-y += exports.o
>> -obj-y += hash.o
>> ifdef CONFIG_SYS_HUSH_PARSER
>> obj-y += cli_hush.o
>> endif
>> @@ -150,6 +149,8 @@ obj-y += fb_nand.o
>> endif
>> endif
>>
>> +obj-y += hash.o
>> +
>> # We always have this since drivers/ddr/fs/interactive.c needs it
>> obj-$(CONFIG_CMDLINE) += cli_simple.o
>>
>> diff --git a/common/image-fit.c b/common/image-fit.c
>> index 25f8a11..12c94e1 100644
>> --- a/common/image-fit.c
>> +++ b/common/image-fit.c
>> @@ -1502,7 +1502,7 @@ void fit_conf_print(const void *fit, int noffset, const char *p)
>>
>> static int fit_image_select(const void *fit, int rd_noffset, int verify)
>> {
>> - fit_image_print(fit, rd_noffset, " ");
>> +// fit_image_print(fit, rd_noffset, " ");
>>
>> if (verify) {
>> puts(" Verifying Hash Integrity ... ");
>> diff --git a/common/spl/spl.c b/common/spl/spl.c
>> index 82e7f58..017ca82 100644
>> --- a/common/spl/spl.c
>> +++ b/common/spl/spl.c
>> @@ -345,6 +345,7 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
>> int i;
>>
>> debug(">>spl:board_init_r()\n");
>> + fit_image_load(NULL, 0, NULL, NULL, 0, 0, 0, 0, NULL, NULL);
>>
>> #if defined(CONFIG_SYS_SPL_MALLOC_START)
>> mem_malloc_init(CONFIG_SYS_SPL_MALLOC_START,
>> diff --git a/configs/firefly-rk3288_defconfig b/configs/firefly-rk3288_defconfig
>> index 0995f9b..596475c 100644
>> --- a/configs/firefly-rk3288_defconfig
>> +++ b/configs/firefly-rk3288_defconfig
>> @@ -69,3 +69,8 @@ CONFIG_USE_PRIVATE_LIBGCC=y
>> CONFIG_USE_TINY_PRINTF=y
>> CONFIG_CMD_DHRYSTONE=y
>> CONFIG_ERRNO_STR=y
>> +CONFIG_SPL_FIT=y
>> +CONFIG_SPL_OF_LIBFDT
>> +CONFIG_FIT_SIGNATURE=y
>> +CONFIG_SPL_FIT_SIGNATURE=y
>> +CONFIG_FIT=y
>> diff --git a/drivers/Makefile b/drivers/Makefile
>> index 6900097..baf9dee 100644
>> --- a/drivers/Makefile
>> +++ b/drivers/Makefile
>> @@ -36,6 +36,7 @@ obj-$(CONFIG_SPL_WATCHDOG_SUPPORT) += watchdog/
>> obj-$(CONFIG_SPL_USB_HOST_SUPPORT) += usb/host/
>> obj-$(CONFIG_OMAP_USB_PHY) += usb/phy/
>> obj-$(CONFIG_SPL_SATA_SUPPORT) += block/
>> +obj-$(CONFIG_SPL_CRYPTO_SUPPORT) += crypto/
>>
>> else
>>
>> diff --git a/include/configs/rk3288_common.h b/include/configs/rk3288_common.h
>> index 8a81397..39bffcb 100644
>> --- a/include/configs/rk3288_common.h
>> +++ b/include/configs/rk3288_common.h
>> @@ -11,6 +11,8 @@
>>
>> #include <asm/arch/hardware.h>
>>
>> +#define CONFIG_SPL_CRYPTO_SUPPORT
>> +
>> #define CONFIG_SYS_NO_FLASH
>> #define CONFIG_NR_DRAM_BANKS 1
>> #define CONFIG_ENV_SIZE 0x2000
>> diff --git a/lib/Makefile b/lib/Makefile
>> index 02dfa29..b3ea4bd 100644
>> --- a/lib/Makefile
>> +++ b/lib/Makefile
>> @@ -9,7 +9,6 @@ ifndef CONFIG_SPL_BUILD
>>
>> obj-$(CONFIG_EFI) += efi/
>> obj-$(CONFIG_EFI_LOADER) += efi_loader/
>> -obj-$(CONFIG_RSA) += rsa/
>> obj-$(CONFIG_LZMA) += lzma/
>> obj-$(CONFIG_LZO) += lzo/
>> obj-$(CONFIG_ZLIB) += zlib/
>> @@ -49,6 +48,8 @@ obj-$(CONFIG_BITREVERSE) += bitrev.o
>> obj-y += list_sort.o
>> endif
>>
>> +obj-$(CONFIG_RSA) += rsa/
>> +
>> obj-$(CONFIG_$(SPL_)OF_LIBFDT) += libfdt/
>> ifdef CONFIG_SPL_OF_CONTROL
>> obj-$(CONFIG_OF_LIBFDT) += libfdt/
>> diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
>> index 60126d2..341ce2e 100644
>> --- a/lib/rsa/rsa-verify.c
>> +++ b/lib/rsa/rsa-verify.c
>> @@ -200,7 +200,10 @@ int rsa_verify(struct image_sign_info *info,
>> }
>>
>> /* Look for a key that matches our hint */
>> - snprintf(name, sizeof(name), "key-%s", info->keyname);
>> + // FIXME
>> + //snprintf(name, sizeof(name), "key-%s", info->keyname);
>> + strcpy(name, "key-");
>> + strcat(name, info->keyname);
>> node = fdt_subnode_offset(blob, sig_node, name);
>> ret = rsa_verify_with_keynode(info, hash, sig, sig_len, node);
>> if (!ret)
>> --
>> 2.8.0.rc3.226.g39d4020
>>
--
Teddy Reed V
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