efi_capsule: Move signature from DTB to .rodata

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.

Reviewed-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Tested-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Tested-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

diff --git a/board/emulation/common/Makefile b/board/emulation/common/Makefile
index 7ed447a..c5b452e 100644 (file)
--- 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 (file)
index 6b8a870..0000000
--- 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 267f1db..ec992b0 100644 (file)
--- 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 7a469f2..dacc3b5 100644 (file)
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -214,6 +214,13 @@ config EFI_CAPSULE_AUTHENTICATE
          Select this option if you want to enable capsule
          authentication
 
+config EFI_CAPSULE_KEY_PATH
+       string "Path to .esl cert for capsule authentication"
+       depends on EFI_CAPSULE_AUTHENTICATE
+       help
+         Provide the EFI signature list (esl) certificate used for capsule
+         authentication
+
 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 fd344ce..9b36943 100644 (file)
--- 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
 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 a09c570..f9b0ef5 100644 (file)
--- 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;
 
+static int efi_get_public_key_data(void **pkey, efi_uintn_t *pkey_len)
+{
+       const void *blob = __efi_capsule_sig_begin;
+       const int len = __efi_capsule_sig_end - __efi_capsule_sig_begin;
+
+       *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 (file)
index 0000000..58f00b8
--- /dev/null
+++ b/lib/efi_loader/efi_capsule_key.S
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * .esl cert for capsule authentication
+ *
+ * Copyright (c) 2021, Ilias Apalodimas <ilias.apalodimas@linaro.org>
+ */
+
+#include <config.h>
+
+.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