Re: [U-Boot] [PATCH] verified-boot: Minimal support for booting U-Boot proper from SPL

30 May 2016

Hi Sumit!
On Sun, May 29, 2016 at 10:32 PM, Sumit Garg sumit.garg@nxp.com wrote:
...
Can you make this support more generic as you have used only CONFIG_SPL_FIT_SIGNATURE for SPL verified boot while our platforms doesn't use fit signature approach for verification?
CONFIG_SPL_FIT_SIGNATURE only adds ./lib/rsa/rsa-{checksum,verify}.c
And the only related change is to mimic the existing
CONFIG_FIT_SIGNATURE option.
This patch only allows an SPL to include the verified boot
implementation from U-Boot proper. I would like to keep it as simple
and concise as possible.
Generalizing the various verified/secure boot methods that exist
within U-Boot would be a much larger effort. :)
...
May be you can use CONFIG_SPL_VERIFIED_BOOT?
In your previous proposed patch [1], I don't see anything modifying
./lib/rsa/rsa-{checksum,verify}.c. The patch does include the
./lib/rsa directory outside of the non-SPL build, but that is not
enough to add the RSA verify and checksum implementationd. I believe
your affected boards will still need CONFIG_FIT_SIGNATURE.
Are you suggesting we should rename CONFIG_FIT_SIGNATURE to
CONFIG_SPL_VERIFIED_BOOT? :)
If that's the case, this patch is NOT the place to perform that
refactor/rename. Since that will also need to update tooling, build
configs, the existing U-Boot proper verified boot documentation, and
several board configurations. It will also render quite a few
guides/walkthroughs obsolete so broader communication may be needed.
[1] http://lists.denx.de/pipermail/u-boot/2016-May/256133.html
...
...
-----Original Message-----
From: Teddy Reed [mailto:teddy.reed@gmail.com]
Sent: Sunday, May 29, 2016 7:28 AM
To: u-boot@lists.denx.de
Cc: sjg@chromium.org; dannenberg@ti.com; Sumit Garg
sumit.garg@nxp.com
Subject: [PATCH] verified-boot: Minimal support for booting U-Boot proper
from SPL
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 only 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
Cc: Simon Glass sjg@chromium.org
Cc: Andreas Dannenberg dannenberg@ti.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                         |  4 ++++
 lib/rsa/Makefile                        |  2 +-
 7 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/Kconfig b/Kconfig
index 4b46216..817f4f0 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 0562d5c..e6b0c22
100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -93,6 +93,7 @@ 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-$(CONFIG_SPL_NET_SUPPORT) += miiphyutil.o diff --git
a/drivers/Makefile b/drivers/Makefile index 99dd07f..772d437 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -10,6 +10,7 @@ obj-$(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..3817fb3 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..0df5395 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-$(CONFIG_GZIP_COMPRESSED) += gzip.o @@ -39,9 +36,7 @@ obj-y +=
net_utils.o
 obj-$(CONFIG_PHYSMEM) += physmem.o
 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-$(CONFIG_RBTREE) += rbtree.o
@@ -49,6 +44,10 @@ obj-$(CONFIG_BITREVERSE) += bitrev.o  obj-y +=
list_sort.o  endif
+obj-$(CONFIG_$(SPL_)RSA) += rsa/
+obj-$(CONFIG_$(SPL_)SHA1) += sha1.o
+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..09ec358 100644
--- a/lib/rsa/Kconfig
+++ b/lib/rsa/Kconfig
@@ -13,6 +13,10 @@ 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"


depends on RSA




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
--
2.7.4
Take care!
-- 
Teddy Reed V

    