This command allows us to add a certificate (or public key) to dtb blob: { signature { capsule-key = "..."; }; }
The value is actually a signature list in terms of UEFI specificaion, and used in verifying UEFI capsules.
The code was originally developed by Sughosh and derived from mkeficapsule.c.
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- Makefile | 2 +- tools/Makefile | 2 + tools/fdtsig.c | 274 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 277 insertions(+), 1 deletion(-) create mode 100644 tools/fdtsig.c
diff --git a/Makefile b/Makefile index 9806464357e0..8b40987234a0 100644 --- a/Makefile +++ b/Makefile @@ -1016,7 +1016,7 @@ quiet_cmd_lzma = LZMA $@ cmd_lzma = lzma -c -z -k -9 $< > $@
quiet_cmd_fdtsig = FDTSIG $@ -cmd_fdtsig = $(srctree)/tools/fdtsig.sh $(CONFIG_EFI_PKEY_FILE) $@ +cmd_fdtsig = $(objtree)/tools/fdtsig -K $(CONFIG_EFI_PKEY_FILE) -D $@
cfg: u-boot.cfg
diff --git a/tools/Makefile b/tools/Makefile index 71a52719620c..e6fd1dbade19 100644 --- a/tools/Makefile +++ b/tools/Makefile @@ -234,6 +234,8 @@ HOSTCFLAGS_asn1_compiler.o = -idirafter $(srctree)/include ifneq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE),) HOSTLDLIBS_mkeficapsule += \ $(shell pkg-config --libs libssl libcrypto 2> /dev/null || echo "-lssl -lcrypto") + fdtsig-objs := fdtsig.o $(LIBFDT_OBJS) + hostprogs-y += fdtsig endif hostprogs-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += mkeficapsule
diff --git a/tools/fdtsig.c b/tools/fdtsig.c new file mode 100644 index 000000000000..daa1e63c3b33 --- /dev/null +++ b/tools/fdtsig.c @@ -0,0 +1,274 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2021 Linaro Limited + * The code in this file was extracted from mkeficapsule.c + */ + +#include <errno.h> +#include <fcntl.h> +#include <getopt.h> +#include <malloc.h> +#include <stdbool.h> +#include <stdio.h> +#include <unistd.h> + +#include <sys/mman.h> +#include <sys/stat.h> + +#include <linux/libfdt.h> + +#define SIGNATURE_NODENAME "signature" +#define OVERLAY_NODENAME "__overlay__" + +static const char *tool_name = "fdtsig"; + +static const char *opts_short = "D:K:Oh"; + +static struct option options[] = { + {"dtb", required_argument, NULL, 'D'}, + {"public key", required_argument, NULL, 'K'}, + {"overlay", no_argument, NULL, 'O'}, + {"help", no_argument, NULL, 'h'}, + {NULL, 0, NULL, 0}, +}; + +static void print_usage(void) +{ + printf("Usage: %s [options]\n" + "Options:\n" + + "\t-K, --public-key <key file> public key esl file\n" + "\t-D, --dtb <dtb file> dtb file\n" + "\t-O, --overlay the dtb file is an overlay\n" + "\t-h, --help print a help message\n", + tool_name); +} + +static int fdt_add_pub_key_data(void *sptr, void *dptr, size_t key_size, + bool overlay) +{ + int parent; + int ov_node; + int frag_node; + int ret = 0; + + if (overlay) { + /* + * The signature would be stored in the + * first fragment node of the overlay + */ + frag_node = fdt_first_subnode(dptr, 0); + if (frag_node == -FDT_ERR_NOTFOUND) { + fprintf(stderr, + "Couldn't find the fragment node: %s\n", + fdt_strerror(frag_node)); + goto done; + } + + ov_node = fdt_subnode_offset(dptr, frag_node, OVERLAY_NODENAME); + if (ov_node == -FDT_ERR_NOTFOUND) { + fprintf(stderr, + "Couldn't find the __overlay__ node: %s\n", + fdt_strerror(ov_node)); + goto done; + } + } else { + ov_node = 0; + } + + parent = fdt_subnode_offset(dptr, ov_node, SIGNATURE_NODENAME); + if (parent == -FDT_ERR_NOTFOUND) { + parent = fdt_add_subnode(dptr, ov_node, SIGNATURE_NODENAME); + if (parent < 0) { + ret = parent; + if (ret != -FDT_ERR_NOSPACE) { + fprintf(stderr, + "Couldn't create signature node: %s\n", + fdt_strerror(parent)); + } + } + } + if (ret) + goto done; + + /* Write the key to the FDT node */ + ret = fdt_setprop(dptr, parent, "capsule-key", + sptr, key_size); + +done: + if (ret) + ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO; + + return ret; +} + +static int add_public_key(const char *pkey_file, const char *dtb_file, + bool overlay) +{ + int ret; + int srcfd = -1; + int destfd = -1; + void *sptr = NULL; + void *dptr = NULL; + off_t src_size; + struct stat pub_key; + struct stat dtb; + + /* Find out the size of the public key */ + srcfd = open(pkey_file, O_RDONLY); + if (srcfd == -1) { + fprintf(stderr, "%s: Can't open %s: %s\n", + __func__, pkey_file, strerror(errno)); + ret = -1; + goto err; + } + + ret = fstat(srcfd, &pub_key); + if (ret == -1) { + fprintf(stderr, "%s: Can't stat %s: %s\n", + __func__, pkey_file, strerror(errno)); + ret = -1; + goto err; + } + + src_size = pub_key.st_size; + + /* mmap the public key esl file */ + sptr = mmap(0, src_size, PROT_READ, MAP_SHARED, srcfd, 0); + if (sptr == MAP_FAILED) { + fprintf(stderr, "%s: Failed to mmap %s:%s\n", + __func__, pkey_file, strerror(errno)); + ret = -1; + goto err; + } + + /* Open the dest FDT */ + destfd = open(dtb_file, O_RDWR); + if (destfd == -1) { + fprintf(stderr, "%s: Can't open %s: %s\n", + __func__, dtb_file, strerror(errno)); + ret = -1; + goto err; + } + + ret = fstat(destfd, &dtb); + if (ret == -1) { + fprintf(stderr, "%s: Can't stat %s: %s\n", + __func__, dtb_file, strerror(errno)); + goto err; + } + + dtb.st_size += src_size + 0x30; + if (ftruncate(destfd, dtb.st_size)) { + fprintf(stderr, "%s: Can't expand %s: %s\n", + __func__, dtb_file, strerror(errno)); + ret = -1; + goto err; + } + + errno = 0; + /* mmap the dtb file */ + dptr = mmap(0, dtb.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, + destfd, 0); + if (dptr == MAP_FAILED) { + fprintf(stderr, "%s: Failed to mmap %s:%s\n", + __func__, dtb_file, strerror(errno)); + ret = -1; + goto err; + } + + if (fdt_check_header(dptr)) { + fprintf(stderr, "%s: Invalid FDT header\n", __func__); + ret = -1; + goto err; + } + + ret = fdt_open_into(dptr, dptr, dtb.st_size); + if (ret) { + fprintf(stderr, "%s: Cannot expand FDT: %s\n", + __func__, fdt_strerror(ret)); + ret = -1; + goto err; + } + + /* Copy the esl file to the expanded FDT */ + ret = fdt_add_pub_key_data(sptr, dptr, src_size, overlay); + if (ret < 0) { + fprintf(stderr, "%s: Unable to add public key to the FDT\n", + __func__); + ret = -1; + goto err; + } + + ret = 0; + +err: + if (sptr) + munmap(sptr, src_size); + + if (dptr) + munmap(dptr, dtb.st_size); + + if (srcfd != -1) + close(srcfd); + + if (destfd != -1) + close(destfd); + + return ret; +} + +int main(int argc, char **argv) +{ + char *pkey_file; + char *dtb_file; + bool overlay; + int c, idx, ret; + + pkey_file = NULL; + dtb_file = NULL; + overlay = false; + + for (;;) { + c = getopt_long(argc, argv, opts_short, options, &idx); + if (c == -1) + break; + + switch (c) { + case 'K': + if (pkey_file) { + printf("Public Key already specified\n"); + return -1; + } + pkey_file = optarg; + break; + case 'D': + if (dtb_file) { + printf("DTB file already specified\n"); + return -1; + } + dtb_file = optarg; + break; + case 'O': + overlay = true; + break; + case 'h': + print_usage(); + return 0; + } + } + + /* check necessary parameters */ + if (!pkey_file || !dtb_file) { + print_usage(); + exit(EXIT_FAILURE); + } + + ret = add_public_key(pkey_file, dtb_file, overlay); + if (ret == -1) { + printf("Adding public key to the dtb failed\n"); + exit(EXIT_FAILURE); + } + + exit(EXIT_SUCCESS); +}