On 08.11.21 16:28, Roman Kopytin wrote:
Having to use the -K option to mkimage to populate U-Boot's .dtb with the public key while signing the kernel FIT image is often a little awkward. In particular, when using a meta-build system such as bitbake/Yocto, having the tasks of the kernel and U-Boot recipes intertwined, modifying deployed artifacts and rebuilding U-Boot with an updated .dtb is quite cumbersome. Also, in some scenarios one may wish to build U-Boot complete with the public key(s) embedded in the .dtb without the corresponding private keys being present on the same build host.
So this adds a simple tool that allows one to disentangle the kernel and U-Boot builds, by simply copy-pasting just enough of the mkimage code to allow one to add a public key to a .dtb. When using mkimage, some of the information is taken from the .its used to build the kernel (algorithm and key name), so that of course needs to be supplied on the command line.
Signed-off-by: Roman Kopytin Roman.Kopytin@kaspersky.com Cc: Rasmus Villemoes rasmus.villemoes@prevas.dk
tools/.gitignore | 1 + tools/Makefile | 3 ++ tools/fdt_add_pubkey.c | 97 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 101 insertions(+) create mode 100755 tools/fdt_add_pubkey.c
diff --git a/tools/.gitignore b/tools/.gitignore index a88453f64d..f312b760e4 100644 --- a/tools/.gitignore +++ b/tools/.gitignore @@ -6,6 +6,7 @@ /dumpimage /easylogo/easylogo /envcrc +/fdt_add_pubkey /fdtgrep /file2include /fit_check_sign diff --git a/tools/Makefile b/tools/Makefile index 4a86321f64..44f25dda18 100644 --- a/tools/Makefile +++ b/tools/Makefile @@ -73,6 +73,7 @@ mkenvimage-objs := mkenvimage.o os_support.o 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_CMD_BOOTEFI_SELFTEST) += file2include
@@ -153,6 +154,7 @@ dumpimage-objs := $(dumpimage-mkimage-objs) dumpimage.o mkimage-objs := $(dumpimage-mkimage-objs) mkimage.o fit_info-objs := $(dumpimage-mkimage-objs) fit_info.o fit_check_sign-objs := $(dumpimage-mkimage-objs) fit_check_sign.o +fdt_add_pubkey-objs := $(dumpimage-mkimage-objs) fdt_add_pubkey.o file2include-objs := file2include.o
ifneq ($(CONFIG_MX23)$(CONFIG_MX28)$(CONFIG_TOOLS_LIBCRYPTO),) @@ -190,6 +192,7 @@ HOSTCFLAGS_fit_image.o += -DMKIMAGE_DTC="$(CONFIG_MKIMAGE_DTC_PATH)" HOSTLDLIBS_dumpimage := $(HOSTLDLIBS_mkimage) HOSTLDLIBS_fit_info := $(HOSTLDLIBS_mkimage) HOSTLDLIBS_fit_check_sign := $(HOSTLDLIBS_mkimage) +HOSTLDLIBS_fdt_add_pubkey := $(HOSTLDLIBS_mkimage)
hostprogs-$(CONFIG_EXYNOS5250) += mkexynosspl hostprogs-$(CONFIG_EXYNOS5420) += mkexynosspl diff --git a/tools/fdt_add_pubkey.c b/tools/fdt_add_pubkey.c new file mode 100755 index 0000000000..9306ecedd1 --- /dev/null +++ b/tools/fdt_add_pubkey.c @@ -0,0 +1,97 @@ +#include <image.h> +#include "fit_common.h"
+static const char *cmdname;
+static const char *algo_name = "sha1,rsa2048"; /* -a <algo> */ +static const char *keydir = "."; /* -k <keydir> */ +static const char *keyname = "key"; /* -n <keyname> */ +static const char *require_keys; /* -r <conf|image> */ +static const char *keydest; /* argv[n] */
+static void usage(const char *msg) +{
- fprintf(stderr, "Error: %s\n", msg);
- fprintf(stderr, "Usage: %s [-a <algo>] [-k <keydir>] [-n <keyname>] [-r <conf|image>] <fdt blob>\n",
cmdname);
The tool should support --help and document the default of these optional parameters that way.
Is there an easy way to derive algo from the key?
Jan