[PATCH 4/6] tools: Add preload_check_sign to authenticate images with a pre-load
Paul HENRYS
paul.henrys_ext at softathome.com
Wed Feb 12 10:31:24 CET 2025
preload_check_sign is added so that it can be used to authenticate images
signed with the pre-load signature supported by binman and U-Boot.
It could also be used to test the signature in binman tests signing
images with the pre-load.
Signed-off-by: Paul HENRYS <paul.henrys_ext at softathome.com>
---
tools/.gitignore | 1 +
tools/Kconfig | 5 ++
tools/Makefile | 5 ++
tools/preload_check_sign.c | 161 +++++++++++++++++++++++++++++++++++++
4 files changed, 172 insertions(+)
create mode 100644 tools/preload_check_sign.c
diff --git a/tools/.gitignore b/tools/.gitignore
index 0108c567309..6a5c613f772 100644
--- a/tools/.gitignore
+++ b/tools/.gitignore
@@ -29,6 +29,7 @@
/mxsboot
/ncb
/prelink-riscv
+/preload_check_sign
/printinitialenv
/proftool
/relocate-rela
diff --git a/tools/Kconfig b/tools/Kconfig
index 01ff0fcf748..8e272ee99a8 100644
--- a/tools/Kconfig
+++ b/tools/Kconfig
@@ -9,6 +9,11 @@ config MKIMAGE_DTC_PATH
some cases the system dtc may not support all required features
and the path to a different version should be given here.
+config TOOLS_IMAGE_PRE_LOAD
+ def_bool y
+ help
+ Enable pre-load signature support in the tools builds.
+
config TOOLS_CRC16
def_bool y
help
diff --git a/tools/Makefile b/tools/Makefile
index 237fa900a24..e5f5eea47c7 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -66,6 +66,7 @@ mkenvimage-objs := mkenvimage.o os_support.o generated/lib/crc32.o
hostprogs-y += dumpimage mkimage
hostprogs-$(CONFIG_TOOLS_LIBCRYPTO) += fit_info fit_check_sign
hostprogs-$(CONFIG_TOOLS_LIBCRYPTO) += fdt_add_pubkey
+hostprogs-$(CONFIG_TOOLS_LIBCRYPTO) += preload_check_sign
ifneq ($(CONFIG_CMD_BOOTEFI_SELFTEST)$(CONFIG_FWU_MDATA_GPT_BLK),)
hostprogs-y += file2include
@@ -89,6 +90,8 @@ ECDSA_OBJS-$(CONFIG_TOOLS_LIBCRYPTO) := $(addprefix generated/lib/ecdsa/, ecdsa-
AES_OBJS-$(CONFIG_TOOLS_LIBCRYPTO) := $(addprefix generated/lib/aes/, \
aes-encrypt.o aes-decrypt.o)
+PRELOAD_OBJS-$(CONFIG_TOOLS_LIBCRYPTO) := generated/boot/image-pre-load.o
+
# Cryptographic helpers and image types that depend on openssl/libcrypto
LIBCRYPTO_OBJS-$(CONFIG_TOOLS_LIBCRYPTO) := \
generated/lib/fdt-libcrypto.o \
@@ -158,6 +161,7 @@ fit_info-objs := $(dumpimage-mkimage-objs) fit_info.o
fit_check_sign-objs := $(dumpimage-mkimage-objs) fit_check_sign.o
fdt_add_pubkey-objs := $(dumpimage-mkimage-objs) fdt_add_pubkey.o
file2include-objs := file2include.o
+preload_check_sign-objs := $(dumpimage-mkimage-objs) $(PRELOAD_OBJS-y) preload_check_sign.o
ifneq ($(CONFIG_MX23)$(CONFIG_MX28)$(CONFIG_TOOLS_LIBCRYPTO),)
# Add CFG_MXS into host CFLAGS, so we can check whether or not register
@@ -195,6 +199,7 @@ HOSTLDLIBS_dumpimage := $(HOSTLDLIBS_mkimage)
HOSTLDLIBS_fit_info := $(HOSTLDLIBS_mkimage)
HOSTLDLIBS_fit_check_sign := $(HOSTLDLIBS_mkimage)
HOSTLDLIBS_fdt_add_pubkey := $(HOSTLDLIBS_mkimage)
+HOSTLDLIBS_preload_check_sign := $(HOSTLDLIBS_mkimage)
hostprogs-$(CONFIG_EXYNOS5250) += mkexynosspl
hostprogs-$(CONFIG_EXYNOS5420) += mkexynosspl
diff --git a/tools/preload_check_sign.c b/tools/preload_check_sign.c
new file mode 100644
index 00000000000..63a778203f0
--- /dev/null
+++ b/tools/preload_check_sign.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Check a file including a preload header including a signature
+ *
+ * Copyright (c) 2025 Paul HENRYS <paul.henrys_ext at softathome.com>
+ *
+ * Binman makes it possible to generate a preload header signing part or the
+ * complete file. The tool preload_check_sign allows to verify and authenticate
+ * a file starting with a preload header.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <openssl/pem.h>
+#include <openssl/evp.h>
+#include <openssl/core_names.h>
+#include <openssl/err.h>
+#include <image.h>
+
+extern void image_pre_load_sig_set_info(struct image_sig_info *info);
+extern int image_pre_load_sig(ulong addr);
+
+static void usage(char *cmdname)
+{
+ fprintf(stderr, "Usage: %s -f file -k PEM key file\n"
+ " -f ==> set file which should be checked\n"
+ " -k ==> PEM key file\n"
+ " -a ==> algo (default: sha256,rsa2048)\n"
+ " -p ==> padding (default: pkcs-1.5)\n"
+ " -h ==> help\n",
+ cmdname);
+ exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv)
+{
+ int ret = 0;
+ char cmdname[256];
+ char *file = NULL;
+ char *keyfile = NULL;
+ int c;
+ FILE *fp = NULL;
+ FILE *fp_key = NULL;
+ size_t bytes;
+ long filesize;
+ void *buffer = NULL;
+ EVP_PKEY *pkey = NULL;
+ char *algo = "sha256,rsa2048";
+ char *padding = "pkcs-1.5";
+ struct image_sig_info info = {0};
+
+ strncpy(cmdname, *argv, sizeof(cmdname) - 1);
+ cmdname[sizeof(cmdname) - 1] = '\0';
+ while ((c = getopt(argc, argv, "f:k:a:p:h")) != -1)
+ switch (c) {
+ case 'f':
+ file = optarg;
+ break;
+ case 'k':
+ keyfile = optarg;
+ break;
+ case 'a':
+ algo = optarg;
+ break;
+ case 'p':
+ padding = optarg;
+ break;
+ default:
+ usage(cmdname);
+ break;
+ }
+
+ if (!file) {
+ fprintf(stderr, "%s: Missing file\n", *argv);
+ usage(*argv);
+ }
+
+ if (!keyfile) {
+ fprintf(stderr, "%s: Missing key file\n", *argv);
+ usage(*argv);
+ }
+
+ fp = fopen(file, "r");
+ if (!fp) {
+ fprintf(stderr, "Error opening file: %s\n", file);
+ ret = EXIT_FAILURE;
+ goto out;
+ }
+
+ fseek(fp, 0, SEEK_END);
+ filesize = ftell(fp);
+ rewind(fp);
+
+ buffer = malloc(filesize);
+ if (!buffer) {
+ fprintf(stderr, "Memory allocation failed");
+ ret = EXIT_FAILURE;
+ goto out;
+ }
+
+ bytes = fread(buffer, 1, filesize, fp);
+ if (bytes != filesize) {
+ fprintf(stderr, "Error reading file\n");
+ ret = EXIT_FAILURE;
+ goto out;
+ }
+
+ fp_key = fopen(keyfile, "r");
+ if (!fp_key) {
+ fprintf(stderr, "Error opening file: %s\n", keyfile);
+ ret = EXIT_FAILURE;
+ goto out;
+ }
+
+ /* Attempt to read the private key */
+ pkey = PEM_read_PrivateKey(fp_key, NULL, NULL, NULL);
+ if (!pkey) {
+ /* If private key reading fails, try reading as a public key */
+ fseek(fp_key, 0, SEEK_SET);
+ pkey = PEM_read_PUBKEY(fp_key, NULL, NULL, NULL);
+ }
+ if (!pkey) {
+ fprintf(stderr, "Unable to retrieve the public key: %s\n",
+ ERR_error_string(ERR_get_error(), NULL));
+ ret = EXIT_FAILURE;
+ goto out;
+ }
+
+ info.algo_name = algo;
+ info.padding_name = padding;
+ info.key = (uint8_t *)pkey;
+ info.mandatory = 1;
+ info.sig_size = (EVP_PKEY_get_bits(pkey) + 7) / 8;
+ if (info.sig_size < 0) {
+ fprintf(stderr, "Fail to retrieve the signature size: %s\n",
+ ERR_error_string(ERR_get_error(), NULL));
+ ret = EXIT_FAILURE;
+ goto out;
+ }
+
+ /* Compute signature information */
+ info.sig_info.name = info.algo_name;
+ info.sig_info.padding = image_get_padding_algo(info.padding_name);
+ info.sig_info.checksum = image_get_checksum_algo(info.sig_info.name);
+ info.sig_info.crypto = image_get_crypto_algo(info.sig_info.name);
+ info.sig_info.key = info.key;
+ info.sig_info.keylen = info.key_len;
+
+ /* Check the signature */
+ image_pre_load_sig_set_info(&info);
+ ret = image_pre_load_sig((ulong)buffer);
+out:
+ if (fp)
+ fclose(fp);
+ if (fp_key)
+ fclose(fp_key);
+ if (info.key)
+ EVP_PKEY_free(pkey);
+ free(buffer);
+
+ exit(ret);
+}
--
2.43.0
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