[PATCH 2/3] Revert "efi_loader: Move public cert for capsules to .rodata"

Simon Glass sjg at chromium.org
Sat May 24 14:09:02 CEST 2025


The dtb part of this patch was rejected a few years ago[1][2]

It seems to have crept in under another name.

With signatures in U-Boot itself it is difficult to insert signatures
after U-Boot itself is built. The devicetree approach is more flexible,
since it can be updates by Binman or other build processes.

This reverts commit 261b422aed7d265c21a8d205f8af9bd31259f5d3.

[1] https://patchwork.ozlabs.org/project/uboot/patch/20210802014621.2280899-1-sjg@chromium.org/
[2] https://lore.kernel.org/u-boot/CAPnjgZ1UiJVHxe2qD3GrYO2LBrXWazXsqP_HYUabOXjKRiPZDA@mail.gmail.com/

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 include/asm-generic/sections.h     |  2 --
 lib/efi_loader/Makefile            | 18 ---------------
 lib/efi_loader/capsule_esl.dtsi.in | 11 +++++++++
 lib/efi_loader/efi_capsule.c       | 37 ++++++++++++++++++++++--------
 lib/efi_loader/efi_capsule_key.S   | 17 --------------
 scripts/Makefile.lib               | 27 ++++++++++++++++++++++
 6 files changed, 66 insertions(+), 46 deletions(-)
 create mode 100644 lib/efi_loader/capsule_esl.dtsi.in
 delete mode 100644 lib/efi_loader/efi_capsule_key.S

diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index d59787948fd..024b1adde27 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -28,8 +28,6 @@ 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/Makefile b/lib/efi_loader/Makefile
index d8864e87052..702d3e79fae 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -29,7 +29,6 @@ obj-y += efi_boottime.o
 obj-y += efi_helper.o
 obj-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += efi_capsule.o
 obj-$(CONFIG_EFI_CAPSULE_FIRMWARE) += efi_firmware.o
-obj-$(CONFIG_EFI_CAPSULE_AUTHENTICATE) += efi_capsule_key.o
 obj-y += efi_console.o
 obj-y += efi_device_path.o
 obj-$(CONFIG_EFI_DEVICE_PATH_TO_TEXT) += efi_device_path_to_text.o
@@ -74,23 +73,6 @@ obj-$(CONFIG_EFI_ECPT) += efi_conformance.o
 EFI_VAR_SEED_FILE := $(subst $\",,$(CONFIG_EFI_VAR_SEED_FILE))
 $(obj)/efi_var_seed.o: $(srctree)/$(EFI_VAR_SEED_FILE)
 
-ifeq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE),y)
-capsule_crt_path=($(subst $(quote),,$(CONFIG_EFI_CAPSULE_CRT_FILE)))
-capsule_crt_full=$(srctree)/$(subst $(quote),,$(CONFIG_EFI_CAPSULE_CRT_FILE))
-quiet_cmd_capsule_esl_gen = CAPSULE_ESL_GEN $@
-cmd_capsule_esl_gen = cert-to-efi-sig-list $(capsule_crt_full) $@
-$(srctree)/capsule_esl_file: FORCE
-	@if [ ! -e "$(capsule_crt_full)" ]; then \
-		echo "ERROR: path $(capsule_crt_full) is invalid." >&2; \
-		echo "EFI CONFIG_EFI_CAPSULE_CRT_FILE must be specified when CONFIG_EFI_CAPSULE_AUTHENTICATE is enabled." >&2; \
-		exit 1; \
-	fi
-	$(call cmd,capsule_esl_gen)
-
-$(obj)/efi_capsule.o: $(srctree)/capsule_esl_file FORCE
-asflags-y += -DCAPSULE_ESL_PATH=\"$(srctree)/capsule_esl_file\"
-endif
-
 # Set the C flags to add and remove for each app
 $(foreach f,$(apps-y),\
 	$(eval CFLAGS_$(f).o := $(CFLAGS_EFI) -Os -ffreestanding)\
diff --git a/lib/efi_loader/capsule_esl.dtsi.in b/lib/efi_loader/capsule_esl.dtsi.in
new file mode 100644
index 00000000000..bc7db836faa
--- /dev/null
+++ b/lib/efi_loader/capsule_esl.dtsi.in
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Devicetree file with the public key EFI Signature List(ESL)
+ * node. This file is used to generate the dtsi file to be
+ * included into the DTB.
+ */
+/ {
+	signature {
+		capsule-key = /incbin/("ESL_BIN_FILE");
+	};
+};
diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
index 1aa52ac7bb6..f8a4a7c6ef4 100644
--- a/lib/efi_loader/efi_capsule.c
+++ b/lib/efi_loader/efi_capsule.c
@@ -22,7 +22,6 @@
 #include <asm/global_data.h>
 #include <u-boot/uuid.h>
 
-#include <asm/sections.h>
 #include <crypto/pkcs7.h>
 #include <crypto/pkcs7_parser.h>
 #include <linux/err.h>
@@ -285,12 +284,33 @@ out:
 }
 
 #if defined(CONFIG_EFI_CAPSULE_AUTHENTICATE)
-static int efi_get_public_key_data(const void **pkey, efi_uintn_t *pkey_len)
+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;
+	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) {
+		log_err("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) {
+		log_err("Unable to get capsule-key value\n");
+		*pkey = NULL;
+		*pkey_len = 0;
+
+		return -FDT_ERR_NOTFOUND;
+	}
 
-	*pkey = blob;
+	*pkey = (void *)blob;
 	*pkey_len = len;
 
 	return 0;
@@ -301,8 +321,7 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
 {
 	u8 *buf;
 	int ret;
-	void *pkey;
-	const void *stored_pkey;
+	void *fdt_pkey, *pkey;
 	efi_uintn_t pkey_len;
 	uint64_t monotonic_count;
 	struct efi_signature_store *truststore;
@@ -354,7 +373,7 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
 		goto out;
 	}
 
-	ret = efi_get_public_key_data(&stored_pkey, &pkey_len);
+	ret = efi_get_public_key_data(&fdt_pkey, &pkey_len);
 	if (ret < 0)
 		goto out;
 
@@ -362,7 +381,7 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
 	if (!pkey)
 		goto out;
 
-	memcpy(pkey, stored_pkey, pkey_len);
+	memcpy(pkey, fdt_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
deleted file mode 100644
index 80cefbe16ae..00000000000
--- a/lib/efi_loader/efi_capsule_key.S
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0+ */
-/*
- * .esl cert for capsule authentication
- *
- * Copyright (c) 2021, Ilias Apalodimas <ilias.apalodimas at linaro.org>
- */
-
-#include <config.h>
-
-.section .rodata.capsule_key.init,"a"
-.balign 16
-.global __efi_capsule_sig_begin
-__efi_capsule_sig_begin:
-.incbin CAPSULE_ESL_PATH
-__efi_capsule_sig_end:
-.global __efi_capsule_sig_end
-.balign 16
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index e89a4a51b74..371f3922e99 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -377,8 +377,35 @@ cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \
 		; \
 	sed "s:$(pre-tmp):$(<):" $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
 
+capsule_esl_input_file=$(srctree)/lib/efi_loader/capsule_esl.dtsi.in
+capsule_crt_file=$(subst $(quote),,$(CONFIG_EFI_CAPSULE_CRT_FILE))
+capsule_esl_dtsi=.capsule_esl.dtsi
+
+quiet_cmd_capsule_esl_gen = CAPSULE_ESL_GEN $@
+cmd_capsule_esl_gen = cert-to-efi-sig-list $< $@
+
+$(obj)/capsule_esl_file: $(capsule_crt_file) FORCE
+ifeq ($(CONFIG_EFI_CAPSULE_CRT_FILE),"")
+	$(error "CONFIG_EFI_CAPSULE_CRT_FILE is empty, EFI capsule authentication \
+	public key must be specified when CONFIG_EFI_CAPSULE_AUTHENTICATE is enabled")
+else
+	$(call cmd,capsule_esl_gen)
+endif
+
+quiet_cmd_capsule_dtsi_gen = CAPSULE_DTSI_GEN $@
+cmd_capsule_dtsi_gen = \
+	$(shell sed "s:ESL_BIN_FILE:$(abspath $<):" $(capsule_esl_input_file) > $@)
+
+$(obj)/$(capsule_esl_dtsi): $(obj)/capsule_esl_file FORCE
+	$(call cmd,capsule_dtsi_gen)
+
 dtsi_include_list_deps := $(addprefix $(u_boot_dtsi_loc),$(subst $(quote),,$(dtsi_include_list)))
 
+ifdef CONFIG_EFI_CAPSULE_AUTHENTICATE
+dtsi_include_list += $(capsule_esl_dtsi)
+dtsi_include_list_deps += $(obj)/$(capsule_esl_dtsi)
+endif
+
 ifneq ($(CHECK_DTBS),)
 DT_CHECKER ?= dt-validate
 DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),-l $(DT_SCHEMA_FILES),-m)
-- 
2.34.1



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