[U-Boot] [PATCH] verified-boot: Minimal support for booting U-Boot proper from SPL
Teddy Reed
teddy.reed at gmail.com
Sun Jun 5 23:27:38 CEST 2016
On Wed, Jun 1, 2016 at 9:40 PM, Sumit Garg <sumit.garg at nxp.com> wrote:
>> -----Original Message-----
>> From: Teddy Reed [mailto:teddy.reed at gmail.com]
>> Sent: Tuesday, May 31, 2016 2:23 AM
>> To: Sumit Garg <sumit.garg at nxp.com>
>> Cc: sjg at chromium.org; dannenberg at ti.com; u-boot at lists.denx.de; Ruchika
>> Gupta <ruchika.gupta at nxp.com>; Aneesh Bansal <aneesh.bansal at nxp.com>
>> Subject: Re: [PATCH] verified-boot: Minimal support for booting U-Boot proper
>> from SPL
>>
>> Hi Sumit!
>>
>> On Sun, May 29, 2016 at 10:32 PM, Sumit Garg <sumit.garg at 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.
>
> Yeah you are correct this patch is not meant for refactoring. So rather I will define
> only CONFIG_SPL_CRYPTO_SUPPORT, CONFIG_SPL_RSA & CONFIG_SPL_HASH_SUPPORT
> for our platform and skip CONFIG_SPL_FIT_SIGNATURE.
>
Ok, sounds like a plan. :)
>>
>> [1] http://lists.denx.de/pipermail/u-boot/2016-May/256133.html
>>
>> >> -----Original Message-----
>> >> From: Teddy Reed [mailto:teddy.reed at gmail.com]
>> >> Sent: Sunday, May 29, 2016 7:28 AM
>> >> To: u-boot at lists.denx.de
>> >> Cc: sjg at chromium.org; dannenberg at ti.com; Sumit Garg
>> >> <sumit.garg at 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 at gmail.com>
>> >> Cc: Simon Glass <sjg at chromium.org>
>> >> Cc: Andreas Dannenberg <dannenberg at 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
>
> Sorry for late response. I will try to rebase my patches using this patch. Also let me
> know should I send those patches in parallel with this patch or wait for acceptance of
> this patch?
Either way, I think a rebase will not have any dependencies (ideally),
but you also wont have any verified boot in SPL until [1] lands. :)
I have not seen any changes/clarifications requested. And I think
Simon usually pulls in verified boot changes into his custodian -fdt
tree. But I am very new to U-Boot development.
[1] https://patchwork.ozlabs.org/patch/627664/
--
Teddy Reed V
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