mirror of
https://github.com/AsahiLinux/u-boot
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0abe3323f5
Just like we exclude data-size, data-position, and data-offset from fit_config_check_sig, we must exclude them while signing as well. While we're at it, use the FIT_DATA_* defines for fit_config_check_sig as welll. Fixes:8edecd3110
("fit: Fix verification of images with external data") Fixes:c522949a29
("rsa: sig: fix config signature check for fit with padding") Signed-off-by: Sean Anderson <sean.anderson@seco.com> Reviewed-by: Simon Glass <sjg@chromium.org>
551 lines
14 KiB
C
551 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2013, Google Inc.
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*/
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#ifdef USE_HOSTCC
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#include "mkimage.h"
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#include <time.h>
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#else
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#include <common.h>
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#include <log.h>
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#include <malloc.h>
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#include <asm/global_data.h>
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DECLARE_GLOBAL_DATA_PTR;
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#endif /* !USE_HOSTCC*/
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#include <fdt_region.h>
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#include <image.h>
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#include <u-boot/rsa.h>
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#include <u-boot/hash-checksum.h>
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#define IMAGE_MAX_HASHED_NODES 100
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/**
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* fit_region_make_list() - Make a list of image regions
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*
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* Given a list of fdt_regions, create a list of image_regions. This is a
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* simple conversion routine since the FDT and image code use different
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* structures.
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*
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* @fit: FIT image
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* @fdt_regions: Pointer to FDT regions
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* @count: Number of FDT regions
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* @region: Pointer to image regions, which must hold @count records. If
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* region is NULL, then (except for an SPL build) the array will be
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* allocated.
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* @return: Pointer to image regions
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*/
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struct image_region *fit_region_make_list(const void *fit,
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struct fdt_region *fdt_regions,
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int count,
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struct image_region *region)
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{
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int i;
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debug("Hash regions:\n");
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debug("%10s %10s\n", "Offset", "Size");
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/*
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* Use malloc() except in SPL (to save code size). In SPL the caller
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* must allocate the array.
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*/
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if (!IS_ENABLED(CONFIG_SPL_BUILD) && !region)
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region = calloc(sizeof(*region), count);
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if (!region)
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return NULL;
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for (i = 0; i < count; i++) {
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debug("%10x %10x\n", fdt_regions[i].offset,
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fdt_regions[i].size);
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region[i].data = fit + fdt_regions[i].offset;
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region[i].size = fdt_regions[i].size;
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}
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return region;
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}
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static int fit_image_setup_verify(struct image_sign_info *info,
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const void *fit, int noffset,
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const void *key_blob, int required_keynode,
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char **err_msgp)
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{
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const char *algo_name;
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const char *padding_name;
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if (fdt_totalsize(fit) > CONFIG_VAL(FIT_SIGNATURE_MAX_SIZE)) {
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*err_msgp = "Total size too large";
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return 1;
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}
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if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
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*err_msgp = "Can't get hash algo property";
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return -1;
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}
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padding_name = fdt_getprop(fit, noffset, "padding", NULL);
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if (!padding_name)
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padding_name = RSA_DEFAULT_PADDING_NAME;
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memset(info, '\0', sizeof(*info));
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info->keyname = fdt_getprop(fit, noffset, FIT_KEY_HINT, NULL);
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info->fit = fit;
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info->node_offset = noffset;
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info->name = algo_name;
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info->checksum = image_get_checksum_algo(algo_name);
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info->crypto = image_get_crypto_algo(algo_name);
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info->padding = image_get_padding_algo(padding_name);
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info->fdt_blob = key_blob;
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info->required_keynode = required_keynode;
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printf("%s:%s", algo_name, info->keyname);
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if (!info->checksum || !info->crypto || !info->padding) {
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*err_msgp = "Unknown signature algorithm";
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return -1;
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}
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return 0;
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}
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int fit_image_check_sig(const void *fit, int noffset, const void *data,
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size_t size, const void *key_blob, int required_keynode,
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char **err_msgp)
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{
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struct image_sign_info info;
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struct image_region region;
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uint8_t *fit_value;
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int fit_value_len;
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*err_msgp = NULL;
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if (fit_image_setup_verify(&info, fit, noffset, key_blob,
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required_keynode, err_msgp))
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return -1;
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if (fit_image_hash_get_value(fit, noffset, &fit_value,
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&fit_value_len)) {
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*err_msgp = "Can't get hash value property";
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return -1;
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}
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region.data = data;
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region.size = size;
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if (info.crypto->verify(&info, ®ion, 1, fit_value, fit_value_len)) {
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*err_msgp = "Verification failed";
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return -1;
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}
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return 0;
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}
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static int fit_image_verify_sig(const void *fit, int image_noffset,
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const char *data, size_t size,
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const void *key_blob, int key_offset)
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{
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int noffset;
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char *err_msg = "";
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int verified = 0;
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int ret;
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/* Process all hash subnodes of the component image node */
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fdt_for_each_subnode(noffset, fit, image_noffset) {
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const char *name = fit_get_name(fit, noffset, NULL);
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/*
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* We don't support this since libfdt considers names with the
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* name root but different @ suffix to be equal
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*/
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if (strchr(name, '@')) {
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err_msg = "Node name contains @";
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goto error;
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}
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if (!strncmp(name, FIT_SIG_NODENAME,
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strlen(FIT_SIG_NODENAME))) {
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ret = fit_image_check_sig(fit, noffset, data, size,
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key_blob, -1, &err_msg);
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if (ret) {
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puts("- ");
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} else {
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puts("+ ");
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verified = 1;
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break;
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}
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}
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}
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if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
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err_msg = "Corrupted or truncated tree";
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goto error;
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}
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return verified ? 0 : -EPERM;
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error:
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printf(" error!\n%s for '%s' hash node in '%s' image node\n",
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err_msg, fit_get_name(fit, noffset, NULL),
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fit_get_name(fit, image_noffset, NULL));
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return -1;
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}
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int fit_image_verify_required_sigs(const void *fit, int image_noffset,
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const char *data, size_t size,
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const void *key_blob, int *no_sigsp)
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{
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int verify_count = 0;
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int noffset;
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int key_node;
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/* Work out what we need to verify */
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*no_sigsp = 1;
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key_node = fdt_subnode_offset(key_blob, 0, FIT_SIG_NODENAME);
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if (key_node < 0) {
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debug("%s: No signature node found: %s\n", __func__,
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fdt_strerror(key_node));
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return 0;
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}
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fdt_for_each_subnode(noffset, key_blob, key_node) {
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const char *required;
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int ret;
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required = fdt_getprop(key_blob, noffset, FIT_KEY_REQUIRED,
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NULL);
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if (!required || strcmp(required, "image"))
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continue;
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ret = fit_image_verify_sig(fit, image_noffset, data, size,
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key_blob, noffset);
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if (ret) {
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printf("Failed to verify required signature '%s'\n",
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fit_get_name(key_blob, noffset, NULL));
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return ret;
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}
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verify_count++;
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}
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if (verify_count)
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*no_sigsp = 0;
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return 0;
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}
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/**
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* fit_config_check_sig() - Check the signature of a config
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*
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* Here we are looking at a particular signature that needs verification (here
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* signature-1):
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*
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* configurations {
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* default = "conf-1";
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* conf-1 {
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* kernel = "kernel-1";
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* fdt = "fdt-1";
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* signature-1 {
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* algo = "sha1,rsa2048";
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* value = <...conf 1 signature...>;
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* };
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* };
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*
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* @fit: FIT to check
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* @noffset: Offset of the signature node being checked (e.g.
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* /configurations/conf-1/signature-1)
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* @conf_noffset: Offset of configuration node (e.g. /configurations/conf-1)
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* @key_blob: Blob containing the keys to check against
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* @required_keynode: Offset in @key_blob of the required key node,
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* if any. If this is given, then the configuration wil not
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* pass verification unless that key is used. If this is
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* -1 then any signature will do.
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* @err_msgp: In the event of an error, this will be pointed to a
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* help error string to display to the user.
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* Return: 0 if all verified ok, <0 on error
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*/
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static int fit_config_check_sig(const void *fit, int noffset, int conf_noffset,
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const void *key_blob, int required_keynode,
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char **err_msgp)
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{
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static char * const exc_prop[] = {
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FIT_DATA_PROP,
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FIT_DATA_SIZE_PROP,
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FIT_DATA_POSITION_PROP,
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FIT_DATA_OFFSET_PROP,
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};
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const char *prop, *end, *name;
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struct image_sign_info info;
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const uint32_t *strings;
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const char *config_name;
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uint8_t *fit_value;
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int fit_value_len;
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bool found_config;
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int max_regions;
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int i, prop_len;
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char path[200];
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int count;
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config_name = fit_get_name(fit, conf_noffset, NULL);
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debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, key_blob,
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fit_get_name(fit, noffset, NULL),
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fit_get_name(key_blob, required_keynode, NULL));
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*err_msgp = NULL;
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if (fit_image_setup_verify(&info, fit, noffset, key_blob,
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required_keynode, err_msgp))
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return -1;
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if (fit_image_hash_get_value(fit, noffset, &fit_value,
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&fit_value_len)) {
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*err_msgp = "Can't get hash value property";
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return -1;
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}
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/* Count the number of strings in the property */
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prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
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end = prop ? prop + prop_len : prop;
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for (name = prop, count = 0; name < end; name++)
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if (!*name)
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count++;
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if (!count) {
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*err_msgp = "Can't get hashed-nodes property";
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return -1;
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}
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if (prop && prop_len > 0 && prop[prop_len - 1] != '\0') {
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*err_msgp = "hashed-nodes property must be null-terminated";
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return -1;
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}
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/* Add a sanity check here since we are using the stack */
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if (count > IMAGE_MAX_HASHED_NODES) {
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*err_msgp = "Number of hashed nodes exceeds maximum";
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return -1;
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}
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/* Create a list of node names from those strings */
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char *node_inc[count];
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debug("Hash nodes (%d):\n", count);
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found_config = false;
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for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
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debug(" '%s'\n", name);
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node_inc[i] = (char *)name;
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if (!strncmp(FIT_CONFS_PATH, name, strlen(FIT_CONFS_PATH)) &&
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name[sizeof(FIT_CONFS_PATH) - 1] == '/' &&
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!strcmp(name + sizeof(FIT_CONFS_PATH), config_name)) {
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debug(" (found config node %s)", config_name);
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found_config = true;
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}
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}
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if (!found_config) {
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*err_msgp = "Selected config not in hashed nodes";
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return -1;
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}
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/*
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* Each node can generate one region for each sub-node. Allow for
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* 7 sub-nodes (hash-1, signature-1, etc.) and some extra.
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*/
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max_regions = 20 + count * 7;
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struct fdt_region fdt_regions[max_regions];
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/* Get a list of regions to hash */
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count = fdt_find_regions(fit, node_inc, count,
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exc_prop, ARRAY_SIZE(exc_prop),
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fdt_regions, max_regions - 1,
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path, sizeof(path), 0);
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if (count < 0) {
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*err_msgp = "Failed to hash configuration";
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return -1;
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}
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if (count == 0) {
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*err_msgp = "No data to hash";
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return -1;
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}
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if (count >= max_regions - 1) {
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*err_msgp = "Too many hash regions";
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return -1;
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}
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/* Add the strings */
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strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
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if (strings) {
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/*
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* The strings region offset must be a static 0x0.
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* This is set in tool/image-host.c
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*/
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fdt_regions[count].offset = fdt_off_dt_strings(fit);
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fdt_regions[count].size = fdt32_to_cpu(strings[1]);
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count++;
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}
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/* Allocate the region list on the stack */
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struct image_region region[count];
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fit_region_make_list(fit, fdt_regions, count, region);
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if (info.crypto->verify(&info, region, count, fit_value,
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fit_value_len)) {
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*err_msgp = "Verification failed";
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return -1;
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}
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return 0;
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}
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/**
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* fit_config_verify_key() - Verify that a configuration is signed with a key
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*
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* Here we are looking at a particular configuration that needs verification:
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*
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* configurations {
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* default = "conf-1";
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* conf-1 {
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* kernel = "kernel-1";
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* fdt = "fdt-1";
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* signature-1 {
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* algo = "sha1,rsa2048";
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* value = <...conf 1 signature...>;
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* };
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* };
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*
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* We must check each of the signature subnodes of conf-1. Hopefully one of them
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* will match the key at key_offset.
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*
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* @fit: FIT to check
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* @conf_noffset: Offset of the configuration node to check (e.g.
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* /configurations/conf-1)
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* @key_blob: Blob containing the keys to check against
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* @key_offset: Offset of the key to check within @key_blob
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* @return 0 if OK, -EPERM if any signatures did not verify, or the
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* configuration node has an invalid name
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*/
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static int fit_config_verify_key(const void *fit, int conf_noffset,
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const void *key_blob, int key_offset)
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{
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int noffset;
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char *err_msg = "No 'signature' subnode found";
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int verified = 0;
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int ret;
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/* Process all hash subnodes of the component conf node */
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fdt_for_each_subnode(noffset, fit, conf_noffset) {
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const char *name = fit_get_name(fit, noffset, NULL);
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if (!strncmp(name, FIT_SIG_NODENAME,
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strlen(FIT_SIG_NODENAME))) {
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ret = fit_config_check_sig(fit, noffset, conf_noffset,
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key_blob, key_offset,
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&err_msg);
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if (ret) {
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puts("- ");
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} else {
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puts("+ ");
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verified = 1;
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break;
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}
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}
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}
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if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
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err_msg = "Corrupted or truncated tree";
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goto error;
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}
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if (verified)
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return 0;
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error:
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printf(" error!\n%s for '%s' hash node in '%s' config node\n",
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err_msg, fit_get_name(fit, noffset, NULL),
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fit_get_name(fit, conf_noffset, NULL));
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return -EPERM;
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}
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/**
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* fit_config_verify_required_keys() - verify any required signatures for config
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*
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* This looks through all the signatures we expect and verifies that at least
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* all the required ones are valid signatures for the configuration
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*
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* @fit: FIT to check
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* @conf_noffset: Offset of the configuration node to check (e.g.
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* /configurations/conf-1)
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* @key_blob: Blob containing the keys to check against
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* @return 0 if OK, -EPERM if any signatures did not verify, or the
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* configuration node has an invalid name
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*/
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static int fit_config_verify_required_keys(const void *fit, int conf_noffset,
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const void *key_blob)
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{
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const char *name = fit_get_name(fit, conf_noffset, NULL);
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int noffset;
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int key_node;
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int verified = 0;
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int reqd_sigs = 0;
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bool reqd_policy_all = true;
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const char *reqd_mode;
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/*
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* We don't support this since libfdt considers names with the
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* name root but different @ suffix to be equal
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*/
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if (strchr(name, '@')) {
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printf("Configuration node '%s' contains '@'\n", name);
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return -EPERM;
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}
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/* Work out what we need to verify */
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key_node = fdt_subnode_offset(key_blob, 0, FIT_SIG_NODENAME);
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if (key_node < 0) {
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debug("%s: No signature node found: %s\n", __func__,
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fdt_strerror(key_node));
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return 0;
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}
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|
|
|
/* Get required-mode policy property from DTB */
|
|
reqd_mode = fdt_getprop(key_blob, key_node, "required-mode", NULL);
|
|
if (reqd_mode && !strcmp(reqd_mode, "any"))
|
|
reqd_policy_all = false;
|
|
|
|
debug("%s: required-mode policy set to '%s'\n", __func__,
|
|
reqd_policy_all ? "all" : "any");
|
|
|
|
/*
|
|
* The algorithm here is a little convoluted due to how we want it to
|
|
* work. Here we work through each of the signature nodes in the
|
|
* public-key area. These are in the U-Boot control devicetree. Each
|
|
* node was created by signing a configuration, so we check if it is
|
|
* 'required' and if so, request that it be verified.
|
|
*/
|
|
fdt_for_each_subnode(noffset, key_blob, key_node) {
|
|
const char *required;
|
|
int ret;
|
|
|
|
required = fdt_getprop(key_blob, noffset, FIT_KEY_REQUIRED,
|
|
NULL);
|
|
if (!required || strcmp(required, "conf"))
|
|
continue;
|
|
|
|
reqd_sigs++;
|
|
|
|
ret = fit_config_verify_key(fit, conf_noffset, key_blob,
|
|
noffset);
|
|
if (ret) {
|
|
if (reqd_policy_all) {
|
|
printf("Failed to verify required signature '%s'\n",
|
|
fit_get_name(key_blob, noffset, NULL));
|
|
return ret;
|
|
}
|
|
} else {
|
|
verified++;
|
|
if (!reqd_policy_all)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (reqd_sigs && !verified) {
|
|
printf("Failed to verify 'any' of the required signature(s)\n");
|
|
return -EPERM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int fit_config_verify(const void *fit, int conf_noffset)
|
|
{
|
|
return fit_config_verify_required_keys(fit, conf_noffset,
|
|
gd_fdt_blob());
|
|
}
|