[PATCH 1/3] efi_capsule: Move signature from DTB to .rodata
Takahiro Akashi
takahiro.akashi at linaro.org
Fri Jul 16 15:39:03 CEST 2021
Just a few minor comments:
On Fri, Jul 16, 2021 at 02:57:00PM +0900, Masami Hiramatsu wrote:
> 2021年7月16日(金) 2:00 Ilias Apalodimas <ilias.apalodimas at linaro.org>:
> >
> > The capsule signature is now part of our DTB. This is problematic when a
> > user is allowed to change/fixup that DTB from U-Boots command line since he
> > can overwrite the signature as well.
> > So Instead of adding the key on the DTB, embed it in the u-boot binary it
> > self as part of it's .rodata. This assumes that the U-Boot binary we load
> > is authenticated by a previous boot stage loader.
> >
>
> I have tested this patch on DeveloperBox.
> Without signing the capsule,
>
> ----
> ** Unrecognized filesystem type **
> Capsule authentication check failed. Aborting update
> Firmware update failed: <NULL>
> Applying capsule UBOOT1024.Cap failed
> PlatformLang:
> ----
>
> With signing the capsule (by Takahiro's patch*)
> (*) https://lists.denx.de/pipermail/u-boot/2021-May/449878.html
> ----
> ** Unrecognized filesystem type **
> ####################################################################################################
> ###########################################################################PlatformLang:
> ----
>
> Reviewed-by: Masami Hiramatsu <masami.hiramatsu at linaro.org>
> Tested-by: Masami Hiramatsu <masami.hiramatsu at linaro.org>
>
> IMHO, we should have a command to show that the current U-Boot
> has what certification from the console for debugging.
> (also, need to import Takahiro's patch)
>
> Thank you,
>
> > Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > ---
> > board/emulation/common/Makefile | 1 -
> > board/emulation/common/qemu_capsule.c | 43 ---------------------------
> > include/asm-generic/sections.h | 2 ++
> > lib/efi_loader/Kconfig | 6 ++++
> > lib/efi_loader/Makefile | 8 +++++
> > lib/efi_loader/efi_capsule.c | 18 +++++++++--
> > lib/efi_loader/efi_capsule_key.S | 8 +++++
> > 7 files changed, 39 insertions(+), 47 deletions(-)
> > delete mode 100644 board/emulation/common/qemu_capsule.c
> > create mode 100644 lib/efi_loader/efi_capsule_key.S
> >
> > diff --git a/board/emulation/common/Makefile b/board/emulation/common/Makefile
> > index 7ed447a69dce..c5b452e7e341 100644
> > --- a/board/emulation/common/Makefile
> > +++ b/board/emulation/common/Makefile
> > @@ -2,4 +2,3 @@
> >
> > obj-$(CONFIG_SYS_MTDPARTS_RUNTIME) += qemu_mtdparts.o
> > obj-$(CONFIG_SET_DFU_ALT_INFO) += qemu_dfu.o
> > -obj-$(CONFIG_EFI_CAPSULE_FIRMWARE_MANAGEMENT) += qemu_capsule.o
> > diff --git a/board/emulation/common/qemu_capsule.c b/board/emulation/common/qemu_capsule.c
> > deleted file mode 100644
> > index 6b8a87022a4c..000000000000
> > --- a/board/emulation/common/qemu_capsule.c
> > +++ /dev/null
> > @@ -1,43 +0,0 @@
> > -// SPDX-License-Identifier: GPL-2.0+
> > -/*
> > - * Copyright (c) 2020 Linaro Limited
> > - */
> > -
> > -#include <common.h>
> > -#include <efi_api.h>
> > -#include <efi_loader.h>
> > -#include <env.h>
> > -#include <fdtdec.h>
> > -#include <asm/global_data.h>
> > -
> > -DECLARE_GLOBAL_DATA_PTR;
> > -
> > -int efi_get_public_key_data(void **pkey, efi_uintn_t *pkey_len)
> > -{
> > - const void *fdt_blob = gd->fdt_blob;
> > - const void *blob;
> > - const char *cnode_name = "capsule-key";
> > - const char *snode_name = "signature";
> > - int sig_node;
> > - int len;
> > -
> > - sig_node = fdt_subnode_offset(fdt_blob, 0, snode_name);
> > - if (sig_node < 0) {
> > - EFI_PRINT("Unable to get signature node offset\n");
> > - return -FDT_ERR_NOTFOUND;
> > - }
> > -
> > - blob = fdt_getprop(fdt_blob, sig_node, cnode_name, &len);
> > -
> > - if (!blob || len < 0) {
> > - EFI_PRINT("Unable to get capsule-key value\n");
> > - *pkey = NULL;
> > - *pkey_len = 0;
> > - return -FDT_ERR_NOTFOUND;
> > - }
> > -
> > - *pkey = (void *)blob;
> > - *pkey_len = len;
> > -
> > - return 0;
> > -}
> > diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
> > index 267f1db73f23..ec992b0c2e3f 100644
> > --- a/include/asm-generic/sections.h
> > +++ b/include/asm-generic/sections.h
> > @@ -27,6 +27,8 @@ extern char __efi_helloworld_begin[];
> > extern char __efi_helloworld_end[];
> > extern char __efi_var_file_begin[];
> > extern char __efi_var_file_end[];
> > +extern char __efi_capsule_sig_begin[];
> > +extern char __efi_capsule_sig_end[];
> >
> > /* Private data used by of-platdata devices/uclasses */
> > extern char __priv_data_start[], __priv_data_end[];
> > diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> > index 156b39152112..42f1292fa04b 100644
> > --- a/lib/efi_loader/Kconfig
> > +++ b/lib/efi_loader/Kconfig
> > @@ -213,6 +213,12 @@ config EFI_CAPSULE_AUTHENTICATE
> > Select this option if you want to enable capsule
> > authentication
> >
> > +config EFI_CAPSULE_KEY_PATH
> > + string "Path to .esl file for capsule authentication"
> > + depends on EFI_CAPSULE_AUTHENTICATE
> > + help
> > + Provide the .esl file used for capsule authentication
We might be friendly if we add what "esl" means here.
More importantly, we are able to contain more than one signatures
if we want.
> > +
> > config EFI_DEVICE_PATH_TO_TEXT
> > bool "Device path to text protocol"
> > default y
> > diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
> > index fd344cea29b0..9b369430e258 100644
> > --- a/lib/efi_loader/Makefile
> > +++ b/lib/efi_loader/Makefile
> > @@ -20,11 +20,19 @@ always += helloworld.efi
> > targets += helloworld.o
> > endif
> >
> > +ifeq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE),y)
> > +EFI_CAPSULE_KEY_PATH := $(subst $\",,$(CONFIG_EFI_CAPSULE_KEY_PATH))
> > +ifeq ("$(wildcard $(EFI_CAPSULE_KEY_PATH))","")
> > +$(error .esl cerificate not found. Configure your CONFIG_EFI_CAPSULE_KEY_PATH)
> > +endif
> > +endif
> > +
> > obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
> > obj-$(CONFIG_CMD_BOOTEFI_BOOTMGR) += efi_bootmgr.o
> > obj-y += efi_boottime.o
> > obj-y += efi_helper.o
> > obj-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += efi_capsule.o
> > +obj-$(CONFIG_EFI_CAPSULE_AUTHENTICATE) += efi_capsule_key.o
We should give users another choice here to allow them to add their
own solution for key storage.
Or only enable this line if "CONFIG_EFI_CAPSULE_KEY_PATH" != null?
> > obj-$(CONFIG_EFI_CAPSULE_FIRMWARE) += efi_firmware.o
> > obj-y += efi_console.o
> > obj-y += efi_device_path.o
> > diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
> > index b878e71438b8..50e93cad4ee5 100644
> > --- a/lib/efi_loader/efi_capsule.c
> > +++ b/lib/efi_loader/efi_capsule.c
> > @@ -16,6 +16,7 @@
> > #include <mapmem.h>
> > #include <sort.h>
> >
> > +#include <asm/sections.h>
> > #include <crypto/pkcs7.h>
> > #include <crypto/pkcs7_parser.h>
> > #include <linux/err.h>
> > @@ -222,12 +223,23 @@ skip:
> > const efi_guid_t efi_guid_capsule_root_cert_guid =
> > EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID;
> >
> > +int efi_get_public_key_data(void **pkey, efi_uintn_t *pkey_len)
static?
> > +{
> > + const void *blob = __efi_capsule_sig_begin;
> > + const int len = __efi_capsule_sig_end - __efi_capsule_sig_begin;
It seems that the length can be calculated at compile time.
> > + *pkey = (void *)blob;
> > + *pkey_len = len;
> > +
> > + return 0;
> > +}
> > +
> > efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_size,
> > void **image, efi_uintn_t *image_size)
> > {
> > u8 *buf;
> > int ret;
> > - void *fdt_pkey, *pkey;
> > + void *stored_pkey, *pkey;
> > efi_uintn_t pkey_len;
> > uint64_t monotonic_count;
> > struct efi_signature_store *truststore;
> > @@ -286,7 +298,7 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
> > goto out;
> > }
> >
> > - ret = efi_get_public_key_data(&fdt_pkey, &pkey_len);
> > + ret = efi_get_public_key_data(&stored_pkey, &pkey_len);
> > if (ret < 0)
> > goto out;
> >
> > @@ -294,7 +306,7 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
> > if (!pkey)
> > goto out;
> >
> > - memcpy(pkey, fdt_pkey, pkey_len);
> > + memcpy(pkey, stored_pkey, pkey_len);
> > truststore = efi_build_signature_store(pkey, pkey_len);
> > if (!truststore)
> > goto out;
> > diff --git a/lib/efi_loader/efi_capsule_key.S b/lib/efi_loader/efi_capsule_key.S
> > new file mode 100644
> > index 000000000000..f7047a42e39d
> > --- /dev/null
> > +++ b/lib/efi_loader/efi_capsule_key.S
> > @@ -0,0 +1,8 @@
Should we have "#include <config.h>" here?
Otherwise it looks good.
-Takahiro Akashi
> > +.section .rodata.capsule_key.init,"a"
> > +.balign 16
> > +.global __efi_capsule_sig_begin
> > +__efi_capsule_sig_begin:
> > +.incbin CONFIG_EFI_CAPSULE_KEY_PATH
> > +__efi_capsule_sig_end:
> > +.global __efi_capsule_sig_end
> > +.balign 16
> > --
> > 2.32.0.rc0
> >
>
>
> --
> Masami Hiramatsu
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