Re: [U-Boot] [PATCH] RFC: Secure boot to U-Boot proper from SPL

On Sun, May 1, 2016 at 11:12 AM, Teddy Reed teddy.reed@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@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@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@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