[PATCH v2 3/3] bootm: add initial FIT support
Sascha Hauer
s.hauer at pengutronix.de
Mon Jan 11 01:19:55 PST 2016
On Wed, Jan 06, 2016 at 06:01:31PM +0100, Marc Kleine-Budde wrote:
> From: Jan Luebbe <jlu at pengutronix.de>
>
> This implementation is inspired by U-Boot's FIT support. Instead of
> using libfdt (which does not exist in barebox), configuration signatures
> are verified by using a simplified DT parser based on barebox's own
> code.
>
> Currently, only signed configurations with hashed images are supported,
> as the other variants are less useful for verified boot. Compatible FIT
> images can be created using U-Boot's mkimage tool.
>
> Signed-off-by: Jan Luebbe <jlu at pengutronix.de>
> Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
> ---
> arch/arm/lib/bootm.c | 73 +++++++
> commands/Kconfig | 10 +
> common/Kconfig | 6 +
> common/Makefile | 1 +
> common/image-fit.c | 585 +++++++++++++++++++++++++++++++++++++++++++++++++++
> include/image-fit.h | 42 ++++
> 6 files changed, 717 insertions(+)
> create mode 100644 common/image-fit.c
> create mode 100644 include/image-fit.h
>
> diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
> index 7bb9b436560c..9a78ee85e9be 100644
> --- a/arch/arm/lib/bootm.c
> +++ b/arch/arm/lib/bootm.c
> @@ -553,6 +553,77 @@ BAREBOX_MAGICVAR(aimage_noverwrite_bootargs, "Disable overwrite of the bootargs
> BAREBOX_MAGICVAR(aimage_noverwrite_tags, "Disable overwrite of the tags addr with the one present in aimage");
> #endif
>
> +#include <image-fit.h>
> +
> +static int do_bootm_arm_fit(struct image_data *data)
> +{
> + struct fit_handle *handle;
> + int ret;
> + unsigned long mem_free;
> + unsigned long mem_start, mem_size;
> +
> + handle = fit_open(data->os_file, data->os_num, data->verbose);
> + if (!handle)
> + return -EINVAL;
> +
> + ret = sdram_start_and_size(&mem_start, &mem_size);
> + if (ret)
> + return ret;
> +
> + /* no support for custom load address */
> + data->os_address = mem_start + PAGE_ALIGN(handle->kernel_size * 4);
> + data->os_res = request_sdram_region("fit-kernel", data->os_address, handle->kernel_size);
> + if (!data->os_res) {
> + pr_err("Cannot request region 0x%08lx - 0x%08lx\n",
> + data->os_address, handle->kernel_size);
> + ret = -ENOMEM;
> + goto err_out;
> + }
> + memcpy((void *)data->os_res->start, handle->kernel, handle->kernel_size);
> +
> + /*
> + * Put oftree/initrd close behind compressed kernel image to avoid
> + * placing it outside of the kernels lowmem.
> + */
> + if (handle->initrd_size) {
> + data->initrd_address = PAGE_ALIGN(data->os_res->end + SZ_1M);
> + data->initrd_res = request_sdram_region("fit-initrd", data->initrd_address, handle->initrd_size);
> + if (!data->initrd_res) {
> + ret = -ENOMEM;
> + goto err_out;
> + }
> + memcpy((void *)data->initrd_res->start, handle->initrd, handle->initrd_size);
> + }
> +
> + data->of_root_node = of_unflatten_dtb(handle->oftree);
> + if (!data->of_root_node) {
> + pr_err("unable to unflatten devicetree\n");
> + ret = -EINVAL;
> + goto err_out;
> + }
> +
> + /*
> + * Put devicetree right after initrd if present or after the kernel
> + * if not.
> + */
> + if (data->initrd_res)
> + mem_free = PAGE_ALIGN(data->initrd_res->end);
> + else
> + mem_free = PAGE_ALIGN(data->os_res->end + SZ_1M);
> +
> + return __do_bootm_linux(data, mem_free, 0);
> +
> +err_out:
> + fit_close(handle);
> + return ret;
> +}
> +
> +static struct image_handler arm_fit_handler = {
> + .name = "FIT image",
> + .bootm = do_bootm_arm_fit,
> + .filetype = filetype_oftree,
> +};
> +
> static struct binfmt_hook binfmt_aimage_hook = {
> .type = filetype_aimage,
> .exec = "bootm",
> @@ -578,6 +649,8 @@ static int armlinux_register_image_handler(void)
> register_image_handler(&aimage_handler);
> binfmt_register(&binfmt_aimage_hook);
> }
> + if (IS_BUILTIN(CONFIG_CMD_BOOTM_FITIMAGE))
> + register_image_handler(&arm_fit_handler);
> binfmt_register(&binfmt_arm_zimage_hook);
> binfmt_register(&binfmt_barebox_hook);
>
> diff --git a/commands/Kconfig b/commands/Kconfig
> index 1743670ed33c..3e4a32a416c7 100644
> --- a/commands/Kconfig
> +++ b/commands/Kconfig
> @@ -418,6 +418,16 @@ config CMD_BOOTM_AIMAGE
> help
> Support using Android Images.
>
> +config CMD_BOOTM_FITIMAGE
> + bool
> + prompt "FIT image support"
> + select FITIMAGE
> + depends on CMD_BOOTM && ARM
> + help
> + Support using FIT Images. Have a look at the u-boot source
> + tree in the "doc/uImage.FIT" folder for more information:
> + http://git.denx.de/?p=u-boot.git;a=tree;f=doc/uImage.FIT
> +
> config CMD_BOOTU
> tristate
> default y
> diff --git a/common/Kconfig b/common/Kconfig
> index 8e7950968c3e..d824b5e35f04 100644
> --- a/common/Kconfig
> +++ b/common/Kconfig
> @@ -66,6 +66,12 @@ config UIMAGE
> select CRC32
> bool
>
> +config FITIMAGE
> + bool
> + select OFTREE
> + select DIGEST
> + select CRYPTO_RSA
> +
> config LOGBUF
> bool
>
> diff --git a/common/Makefile b/common/Makefile
> index 56e6becec078..ffaf8e7b42eb 100644
> --- a/common/Makefile
> +++ b/common/Makefile
> @@ -46,6 +46,7 @@ obj-$(CONFIG_SHELL_HUSH) += hush.o
> obj-$(CONFIG_SHELL_SIMPLE) += parser.o
> obj-$(CONFIG_STATE) += state.o
> obj-$(CONFIG_UIMAGE) += image.o uimage.o
> +obj-$(CONFIG_FITIMAGE) += image-fit.o
> obj-$(CONFIG_MENUTREE) += menutree.o
> obj-$(CONFIG_EFI_GUID) += efi-guid.o
> obj-$(CONFIG_EFI_DEVICEPATH) += efi-devicepath.o
> diff --git a/common/image-fit.c b/common/image-fit.c
> new file mode 100644
> index 000000000000..296285b0b44d
> --- /dev/null
> +++ b/common/image-fit.c
> @@ -0,0 +1,585 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, see <http://www.gnu.org/licenses/>.
> + *
> + * Copyright (C) Jan Lübbe, 2014
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <boot.h>
> +#include <libfile.h>
> +#include <fdt.h>
> +#include <digest.h>
> +#include <of.h>
> +#include <fs.h>
> +#include <malloc.h>
> +#include <linux/ctype.h>
> +#include <asm/byteorder.h>
> +#include <errno.h>
> +#include <linux/err.h>
> +#include <stringlist.h>
> +#include <rsa.h>
> +#include <image-fit.h>
> +
> +#define FDT_MAX_DEPTH 32
> +#define FDT_MAX_PATH_LEN 200
> +
> +#define CHECK_LEVEL_NONE 0
> +#define CHECK_LEVEL_HASH 1
> +#define CHECK_LEVEL_SIG 2
> +#define CHECK_LEVEL_MAX 3
> +
> +static uint32_t dt_struct_advance(struct fdt_header *f, uint32_t dt, int size)
> +{
> + dt += size;
> + dt = ALIGN(dt, 4);
> +
> + if (dt > f->off_dt_struct + f->size_dt_struct)
> + return 0;
> +
> + return dt;
> +}
> +
> +static char *dt_string(struct fdt_header *f, char *strstart, uint32_t ofs)
> +{
> + if (ofs > f->size_dt_strings)
> + return NULL;
> + else
> + return strstart + ofs;
> +}
We already have these elsewhere, also as static functions. We should
create global functions for them.
> +
> +static int of_read_string_list(struct device_node *np, const char *name, struct string_list *sl)
> +{
> + struct property *prop;
> + const char *s;
> +
> + of_property_for_each_string(np, name, prop, s) {
> + string_list_add(sl, s);
> + }
> +
> + return prop ? 0 : -EINVAL;
> +}
> +
> +static int fit_digest(void *fit, struct digest *digest,
> + struct string_list *inc_nodes, struct string_list *exc_props,
> + uint32_t hashed_strings_start, uint32_t hashed_strings_size)
> +{
> + struct fdt_header *fdt = fit;
> + uint32_t dt_struct;
> + void *dt_strings;
> + struct fdt_header f;
You do not initialize all fields, it's probably safer to zero it explicitly
here.
> + int stack[FDT_MAX_DEPTH];
> + char path[FDT_MAX_PATH_LEN];
> + char *end;
> + uint32_t tag;
> + int start = -1;
> + int depth = -1;
> + int want = 0;
> +
> + f.totalsize = fdt32_to_cpu(fdt->totalsize);
> + f.off_dt_struct = fdt32_to_cpu(fdt->off_dt_struct);
> + f.size_dt_struct = fdt32_to_cpu(fdt->size_dt_struct);
> + f.off_dt_strings = fdt32_to_cpu(fdt->off_dt_strings);
> + f.size_dt_strings = fdt32_to_cpu(fdt->size_dt_strings);
> +
> + if (hashed_strings_start > f.size_dt_strings ||
> + hashed_strings_size > f.size_dt_strings ||
> + hashed_strings_start + hashed_strings_size > f.size_dt_strings) {
> + pr_err("%s: hashed-strings too large\n", __func__);
> + return -EINVAL;
> + }
> +
> + dt_struct = f.off_dt_struct;
> + dt_strings = (void *)fdt + f.off_dt_strings;
> +
> + end = path;
> + *end = '\0';
> +
> + do {
> + const struct fdt_property *fdt_prop;
> + const struct fdt_node_header *fnh;
> + const char *name;
> + int include = 0;
> + int stop_at = 0;
> + int offset = dt_struct;
> + int maxlen, len;
> +
> + tag = be32_to_cpu(*(uint32_t *)(fit + dt_struct));
> +
> + switch (tag) {
> + case FDT_BEGIN_NODE:
> + fnh = fit + dt_struct;
> + name = fnh->name;
> + maxlen = (unsigned long)fdt + f.off_dt_struct +
> + f.size_dt_struct - (unsigned long)name;
> +
> + len = strnlen(name, maxlen + 1);
> + if (len > maxlen)
> + return -ESPIPE;
> +
> + dt_struct = dt_struct_advance(&f, dt_struct,
> + sizeof(struct fdt_node_header) + len + 1);
> +
> + depth++;
> + if (depth == FDT_MAX_DEPTH)
> + return -ESPIPE;
> + if (end - path + 2 + len >= FDT_MAX_PATH_LEN)
> + return -ESPIPE;
> + if (end != path + 1)
> + *end++ = '/';
> + strcpy(end, name);
> + end += len;
> + stack[depth] = want;
> + if (want == 1)
> + stop_at = offset;
> + if (string_list_contains(inc_nodes, path))
> + want = 2;
> + else if (want)
> + want--;
> + else
> + stop_at = offset;
> + include = want;
> +
> + break;
> +
> + case FDT_END_NODE:
> + dt_struct = dt_struct_advance(&f, dt_struct, FDT_TAGSIZE);
> +
> + include = want;
> + want = stack[depth--];
> + while (end > path && *--end != '/')
> + ;
> + *end = '\0';
> +
> + break;
> +
> + case FDT_PROP:
> + fdt_prop = fit + dt_struct;
> + len = fdt32_to_cpu(fdt_prop->len);
> +
> + name = dt_string(&f, dt_strings, fdt32_to_cpu(fdt_prop->nameoff));
> + if (!name)
> + return -ESPIPE;
> +
> + dt_struct = dt_struct_advance(&f, dt_struct,
> + sizeof(struct fdt_property) + len);
> +
> + include = want >= 2;
> + stop_at = offset;
> + if (string_list_contains(exc_props, name))
> + include = 0;
> +
> + break;
> +
> + case FDT_NOP:
> + dt_struct = dt_struct_advance(&f, dt_struct, FDT_TAGSIZE);
> +
> + include = want >= 2;
> + stop_at = offset;
> +
> + break;
> +
> + case FDT_END:
> + dt_struct = dt_struct_advance(&f, dt_struct, FDT_TAGSIZE);
> +
> + include = 1;
> +
> + break;
> +
> + default:
> + pr_err("%s: Unknown tag 0x%08X\n", __func__, tag);
> + return -EINVAL;
> + }
> +
> + if (!dt_struct)
> + return -ESPIPE;
> +
> + pr_debug("%s: include %d, want %d, offset 0x%x, len 0x%x\n",
> + path, include, want, offset, dt_struct-offset);
> +
> + if (include && start == -1)
> + start = offset;
> +
> + if (!include && start != -1) {
> + pr_debug("region: 0x%p+0x%x\n", fit+start, offset-start);
> + digest_update(digest, fit+start, offset-start);
> + start = -1;
> + }
> + } while (tag != FDT_END);
> +
> + pr_debug("region: 0x%p+0x%x\n", fit+start, dt_struct-start);
> + digest_update(digest, fit+start, dt_struct-start);
Please add whitespaces around binary operators.
> +
> + pr_debug("strings: 0x%p+0x%x\n", dt_strings+hashed_strings_start, hashed_strings_size);
> + digest_update(digest, dt_strings+hashed_strings_start, hashed_strings_size);
> +
> + return 0;
> +}
> +
> +/*
> + * The consistency of the FTD structure was already checked by of_unflatten_dtb()
> + */
> +static int fit_verify_signature(struct device_node *sig_node, void *fit)
> +{
> + uint32_t hashed_strings_start, hashed_strings_size;
> + struct string_list inc_nodes, exc_props;
> + struct rsa_public_key key = {};
> + struct digest *digest;
> + int sig_len;
> + const char *algo_name, *key_name, *sig_value;
> + char *key_path;
> + struct device_node *key_node;
> + enum hash_algo algo;
> + void *hash;
> + int ret;
> +
> + if (of_property_read_string(sig_node, "algo", &algo_name)) {
> + pr_err("algo not found\n");
> + ret = -EINVAL;
> + goto out;
> + }
> + if (strcmp(algo_name, "sha1,rsa2048") == 0) {
> + algo = HASH_ALGO_SHA1;
> + } else if (strcmp(algo_name, "sha256,rsa4096") == 0) {
> + algo = HASH_ALGO_SHA256;
> + } else {
> + pr_err("unknown algo %s\n", algo_name);
> + ret = -EINVAL;
> + goto out;
> + }
> + digest = digest_alloc_by_algo(algo);
> + if (!digest) {
> + pr_err("unsupported algo %s\n", algo_name);
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + sig_value = of_get_property(sig_node, "value", &sig_len);
> + if (!sig_value) {
> + pr_err("signature value not found\n");
> + ret = -EINVAL;
> + goto out_free_digest;
> + }
> +
> + if (of_property_read_string(sig_node, "key-name-hint", &key_name)) {
> + pr_err("key name not found\n");
> + ret = -EINVAL;
> + goto out_free_digest;
> + }
> + key_path = asprintf("/signature/key-%s", key_name);
> + if (!key_name) {
s/key_name/key_path/
> + ret = -ENOMEM;
> + goto out_free_digest;
> + }
> + key_node = of_find_node_by_path(key_path);
> + free(key_path);
> + if (!key_node) {
> + pr_info("failed to find key node\n");
> + ret = -ENOENT;
> + goto out_free_digest;
> + }
> +
> + ret = rsa_of_read_key(key_node, &key);
> + if (ret) {
> + pr_info("failed to read key\n");
> + ret = -ENOENT;
> + goto out_free_digest;
> + }
> +
> + if (of_property_read_u32_index(sig_node, "hashed-strings", 0, &hashed_strings_start)) {
> + pr_err("%s: hashed-strings start not found\n", __func__);
> + ret = -EINVAL;
> + goto out_free_digest;
> + }
> + if (of_property_read_u32_index(sig_node, "hashed-strings", 1, &hashed_strings_size)) {
> + pr_err("%s: hashed-strings size not found\n", __func__);
> + ret = -EINVAL;
> + goto out_free_digest;
> + }
> +
> + string_list_init(&inc_nodes);
> + string_list_init(&exc_props);
> +
> + if (of_read_string_list(sig_node, "hashed-nodes", &inc_nodes)) {
> + pr_err("%s: hashed-nodes invalid\n", __func__);
Please drop the __func__ and add a suitable pr_fmt.
> + ret = -EINVAL;
> + goto out_sl;
> + }
> +
> + string_list_add(&exc_props, "data");
> +
> + digest_init(digest);
> + ret = fit_digest(fit, digest, &inc_nodes, &exc_props, hashed_strings_start, hashed_strings_size);
> + hash = xzalloc(digest_length(digest));
> + digest_final(digest, hash);
> +
> + ret = rsa_verify(&key, sig_value, sig_len, hash, algo);
> + if (ret) {
> + pr_info("FIT image signature BAD\n");
> + ret = CHECK_LEVEL_NONE;
> + } else {
> + pr_info("FIT image signature OK\n");
> + ret = CHECK_LEVEL_SIG;
> + }
> +
> + free(hash);
> + out_sl:
> + string_list_free(&inc_nodes);
> + string_list_free(&exc_props);
> + out_free_digest:
> + digest_free(digest);
> + out:
> + return ret;
> +}
> +
> +static int fit_verify_hash(struct device_node *hash, const void *data, int data_len)
> +{
> + struct digest *d;
> + const char *algo;
> + const char *value_read;
> + char *value_calc;
> + int hash_len;
> +
> + value_read = of_get_property(hash, "value", &hash_len);
> + if (!value_read) {
> + pr_err("%s: value not found\n", hash->full_name);
> + return -EINVAL;
> + }
> +
> + if (of_property_read_string(hash, "algo", &algo)) {
> + pr_err("%s: algo not found\n", hash->full_name);
> + return -EINVAL;
> + }
> +
> + d = digest_alloc(algo);
> + if (!d) {
> + pr_err("%s: unsupported algo %s\n", hash->full_name, algo);
> + return -EINVAL;
> + }
> +
> + if (hash_len != digest_length(d)) {
> + pr_err("%s: invalid hash length %d\n", hash->full_name, hash_len);
> + digest_free(d);
> + return -EINVAL;
> + }
> +
> + value_calc = xmalloc(hash_len);
> +
> + digest_init(d);
> + digest_update(d, data, data_len);
> + digest_final(d, value_calc);
> +
> + if (memcmp(value_read, value_calc, hash_len)) {
> + pr_info("%s: hash BAD\n", hash->full_name);
> + digest_free(d);
> + return CHECK_LEVEL_NONE;
> + } else {
> + pr_info("%s: hash OK\n", hash->full_name);
> + digest_free(d);
> + return CHECK_LEVEL_HASH;
> + }
You can move the digest_free before the if/else.
> +}
> +
> +static int fit_open_image(struct fit_handle *handle, const char* unit)
> +{
> + struct device_node *image = NULL, *hash;
> + const char *type = NULL, *desc= "(no description)";
> + const void *data;
> + int data_len;
> + int ret, level;
> +
> + image = of_get_child_by_name(handle->root, "images");
> + if (!image)
> + return -ENOENT;
> +
> + image = of_get_child_by_name(image, unit);
> + if (!image)
> + return -ENOENT;
> +
> + of_property_read_string(image, "description", &desc);
> + pr_info("FIT image '%s': '%s'\n", unit, desc);
> +
> + of_property_read_string(image, "type", &type);
> + if (!type)
> + return -EINVAL;
> +
> + data = of_get_property(image, "data", &data_len);
> + if (!data) {
> + pr_err("data not found\n");
> + return -EINVAL;
> + }
> +
> + level = CHECK_LEVEL_MAX;
> + for_each_child_of_node(image, hash) {
> + if (handle->verbose)
> + of_print_nodes(hash, 0);
> + ret = fit_verify_hash(hash, data, data_len);
> + if (ret < 0)
> + return ret;
> + level = min(level, ret);
> + }
> + if (level == CHECK_LEVEL_MAX)
> + return -EINVAL;
> +
> + if (level == CHECK_LEVEL_HASH) {
> + if (strcmp(type, "kernel") == 0 ||
> + strcmp(type, "kernel_noload") == 0) {
> + handle->kernel = data;
> + handle->kernel_size = data_len;
> + } else if (strcmp(type, "flat_dt") == 0) {
> + handle->oftree = data;
> + handle->oftree_size = data_len;
> + } else if (strcmp(type, "ramdisk") == 0) {
> + handle->initrd = data;
> + handle->initrd_size = data_len;
> + } else {
> + pr_info("unknown image type %s, ignoring\n", type);
> + }
> + }
> +
> + return level;
> +}
> +
> +static int fit_open_configuration(struct fit_handle *handle, int num)
> +{
> + struct device_node *conf_node = NULL, *sig_node;
> + char unit_name[10];
> + const char *unit, *desc;
> + int ret, level;
> +
> + conf_node = of_get_child_by_name(handle->root, "configurations");
> + if (!conf_node)
> + return -ENOENT;
> +
> + if (num) {
> + snprintf(unit_name, sizeof(unit_name), "conf@%d", num);
> + unit = unit_name;
> + } else if (of_property_read_string(conf_node, "default", &unit)) {
> + unit = "conf at 1";
> + }
> +
> + conf_node = of_get_child_by_name(conf_node, unit);
> + if (!conf_node) {
> + pr_err("FIT configuration '%s' not found\n", unit);
> + return -ENOENT;
> + }
> +
> + if (of_property_read_string(conf_node, "description", &desc)) {
> + pr_info("FIT configuration '%s' (no description)\n", unit);
> + } else {
> + pr_info("FIT configuration '%s': '%s'\n", unit, desc);
> + }
in fit_open_image() desc is initialized with "(no description)". You could
do the same here.
> +struct fit_handle *fit_open(const char *filename, int num, bool verbose)
> +{
> + struct fit_handle *handle = NULL;
> + const char *desc;
> +
> + handle = xzalloc(sizeof(struct fit_handle));
> +
> + handle->verbose = verbose;
>
> + pr_err("unable to read %s: %s\n", filename, strerror(errno));
> + goto err;
> + }
> +
> + handle->root = of_unflatten_dtb(handle->fit);
> + if (IS_ERR(handle->root)) {
> + goto err;
> + }
> +
> + if (of_property_read_string(handle->root, "description", &desc)) {
> + pr_info("FIT '%s' (no description)\n", filename);
> + } else {
> + pr_info("FIT '%s': '%s'\n", filename, desc);
> + }
Same as in fit_open_configuration()
Sascha
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