// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2013, Google Inc.
 */

#ifdef USE_HOSTCC
#include "mkimage.h"
#include <time.h>
#else
#include <common.h>
#include <log.h>
#include <malloc.h>
#include <asm/global_data.h>
DECLARE_GLOBAL_DATA_PTR;
#endif /* !USE_HOSTCC*/
#include <fdt_region.h>
#include <image.h>
#include <u-boot/rsa.h>
#include <u-boot/hash-checksum.h>

#define IMAGE_MAX_HASHED_NODES          100

/**
 * fit_region_make_list() - Make a list of image regions
 *
 * Given a list of fdt_regions, create a list of image_regions. This is a
 * simple conversion routine since the FDT and image code use different
 * structures.
 *
 * @fit: FIT image
 * @fdt_regions: Pointer to FDT regions
 * @count: Number of FDT regions
 * @region: Pointer to image regions, which must hold @count records. If
 * region is NULL, then (except for an SPL build) the array will be
 * allocated.
 * @return: Pointer to image regions
 */
struct image_region *fit_region_make_list(const void *fit,
                                          struct fdt_region *fdt_regions,
                                          int count,
                                          struct image_region *region)
{
        int i;

        debug("Hash regions:\n");
        debug("%10s %10s\n", "Offset", "Size");

        /*
         * Use malloc() except in SPL (to save code size). In SPL the caller
         * must allocate the array.
         */
        if (!IS_ENABLED(CONFIG_SPL_BUILD) && !region)
                region = calloc(sizeof(*region), count);
        if (!region)
                return NULL;
        for (i = 0; i < count; i++) {
                debug("%10x %10x\n", fdt_regions[i].offset,
                      fdt_regions[i].size);
                region[i].data = fit + fdt_regions[i].offset;
                region[i].size = fdt_regions[i].size;
        }

        return region;
}

static int fit_image_setup_verify(struct image_sign_info *info,
                                  const void *fit, int noffset,
                                  const void *key_blob, int required_keynode,
                                  char **err_msgp)
{
        const char *algo_name;
        const char *padding_name;

        if (fdt_totalsize(fit) > CONFIG_VAL(FIT_SIGNATURE_MAX_SIZE)) {
                *err_msgp = "Total size too large";
                return 1;
        }
        if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
                *err_msgp = "Can't get hash algo property";
                return -1;
        }

        padding_name = fdt_getprop(fit, noffset, "padding", NULL);
        if (!padding_name)
                padding_name = RSA_DEFAULT_PADDING_NAME;

        memset(info, '\0', sizeof(*info));
        info->keyname = fdt_getprop(fit, noffset, FIT_KEY_HINT, NULL);
        info->fit = fit;
        info->node_offset = noffset;
        info->name = algo_name;
        info->checksum = image_get_checksum_algo(algo_name);
        info->crypto = image_get_crypto_algo(algo_name);
        info->padding = image_get_padding_algo(padding_name);
        info->fdt_blob = key_blob;
        info->required_keynode = required_keynode;
        printf("%s:%s", algo_name, info->keyname);

        if (!info->checksum || !info->crypto || !info->padding) {
                *err_msgp = "Unknown signature algorithm";
                return -1;
        }

        return 0;
}

int fit_image_check_sig(const void *fit, int noffset, const void *data,
                        size_t size, const void *key_blob, int required_keynode,
                        char **err_msgp)
{
        struct image_sign_info info;
        struct image_region region;
        uint8_t *fit_value;
        int fit_value_len;

        *err_msgp = NULL;
        if (fit_image_setup_verify(&info, fit, noffset, key_blob,
                                   required_keynode, err_msgp))
                return -1;

        if (fit_image_hash_get_value(fit, noffset, &fit_value,
                                     &fit_value_len)) {
                *err_msgp = "Can't get hash value property";
                return -1;
        }

        region.data = data;
        region.size = size;

        if (info.crypto->verify(&info, &region, 1, fit_value, fit_value_len)) {
                *err_msgp = "Verification failed";
                return -1;
        }

        return 0;
}

static int fit_image_verify_sig(const void *fit, int image_noffset,
                                const char *data, size_t size,
                                const void *key_blob, int key_offset)
{
        int noffset;
        char *err_msg = "";
        int verified = 0;
        int ret;

        /* Process all hash subnodes of the component image node */
        fdt_for_each_subnode(noffset, fit, image_noffset) {
                const char *name = fit_get_name(fit, noffset, NULL);

                /*
                 * We don't support this since libfdt considers names with the
                 * name root but different @ suffix to be equal
                 */
                if (strchr(name, '@')) {
                        err_msg = "Node name contains @";
                        goto error;
                }
                if (!strncmp(name, FIT_SIG_NODENAME,
                             strlen(FIT_SIG_NODENAME))) {
                        ret = fit_image_check_sig(fit, noffset, data, size,
                                                  key_blob, -1, &err_msg);
                        if (ret) {
                                puts("- ");
                        } else {
                                puts("+ ");
                                verified = 1;
                                break;
                        }
                }
        }

        if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
                err_msg = "Corrupted or truncated tree";
                goto error;
        }

        return verified ? 0 : -EPERM;

error:
        printf(" error!\n%s for '%s' hash node in '%s' image node\n",
               err_msg, fit_get_name(fit, noffset, NULL),
               fit_get_name(fit, image_noffset, NULL));
        return -1;
}

int fit_image_verify_required_sigs(const void *fit, int image_noffset,
                                   const char *data, size_t size,
                                   const void *key_blob, int *no_sigsp)
{
        int verify_count = 0;
        int noffset;
        int key_node;

        /* Work out what we need to verify */
        *no_sigsp = 1;
        key_node = fdt_subnode_offset(key_blob, 0, FIT_SIG_NODENAME);
        if (key_node < 0) {
                debug("%s: No signature node found: %s\n", __func__,
                      fdt_strerror(key_node));
                return 0;
        }

        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, "image"))
                        continue;
                ret = fit_image_verify_sig(fit, image_noffset, data, size,
                                           key_blob, noffset);
                if (ret) {
                        printf("Failed to verify required signature '%s'\n",
                               fit_get_name(key_blob, noffset, NULL));
                        return ret;
                }
                verify_count++;
        }

        if (verify_count)
                *no_sigsp = 0;

        return 0;
}

/**
 * fit_config_check_sig() - Check the signature of a config
 *
 * Here we are looking at a particular signature that needs verification (here
 * signature-1):
 *
 *      configurations {
 *              default = "conf-1";
 *              conf-1 {
 *                      kernel = "kernel-1";
 *                      fdt = "fdt-1";
 *                      signature-1 {
 *                              algo = "sha1,rsa2048";
 *                              value = <...conf 1 signature...>;
 *                      };
 *              };
 *
 * @fit: FIT to check
 * @noffset: Offset of the signature node being checked (e.g.
 *       /configurations/conf-1/signature-1)
 * @conf_noffset: Offset of configuration node (e.g. /configurations/conf-1)
 * @key_blob: Blob containing the keys to check against
 * @required_keynode:   Offset in @key_blob of the required key node,
 *                      if any. If this is given, then the configuration wil not
 *                      pass verification unless that key is used. If this is
 *                      -1 then any signature will do.
 * @err_msgp:           In the event of an error, this will be pointed to a
 *                      help error string to display to the user.
 * Return: 0 if all verified ok, <0 on error
 */
static int fit_config_check_sig(const void *fit, int noffset, int conf_noffset,
                                const void *key_blob, int required_keynode,
                                char **err_msgp)
{
        static char * const exc_prop[] = {
                "data",
                "data-size",
                "data-position",
                "data-offset"
        };

        const char *prop, *end, *name;
        struct image_sign_info info;
        const uint32_t *strings;
        const char *config_name;
        uint8_t *fit_value;
        int fit_value_len;
        bool found_config;
        int max_regions;
        int i, prop_len;
        char path[200];
        int count;

        config_name = fit_get_name(fit, conf_noffset, NULL);
        debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, key_blob,
              fit_get_name(fit, noffset, NULL),
              fit_get_name(key_blob, required_keynode, NULL));
        *err_msgp = NULL;
        if (fit_image_setup_verify(&info, fit, noffset, key_blob,
                                   required_keynode, err_msgp))
                return -1;

        if (fit_image_hash_get_value(fit, noffset, &fit_value,
                                     &fit_value_len)) {
                *err_msgp = "Can't get hash value property";
                return -1;
        }

        /* Count the number of strings in the property */
        prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
        end = prop ? prop + prop_len : prop;
        for (name = prop, count = 0; name < end; name++)
                if (!*name)
                        count++;
        if (!count) {
                *err_msgp = "Can't get hashed-nodes property";
                return -1;
        }

        if (prop && prop_len > 0 && prop[prop_len - 1] != '\0') {
                *err_msgp = "hashed-nodes property must be null-terminated";
                return -1;
        }

        /* Add a sanity check here since we are using the stack */
        if (count > IMAGE_MAX_HASHED_NODES) {
                *err_msgp = "Number of hashed nodes exceeds maximum";
                return -1;
        }

        /* Create a list of node names from those strings */
        char *node_inc[count];

        debug("Hash nodes (%d):\n", count);
        found_config = false;
        for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
                debug("   '%s'\n", name);
                node_inc[i] = (char *)name;
                if (!strncmp(FIT_CONFS_PATH, name, strlen(FIT_CONFS_PATH)) &&
                    name[sizeof(FIT_CONFS_PATH) - 1] == '/' &&
                    !strcmp(name + sizeof(FIT_CONFS_PATH), config_name)) {
                        debug("      (found config node %s)", config_name);
                        found_config = true;
                }
        }
        if (!found_config) {
                *err_msgp = "Selected config not in hashed nodes";
                return -1;
        }

        /*
         * Each node can generate one region for each sub-node. Allow for
         * 7 sub-nodes (hash-1, signature-1, etc.) and some extra.
         */
        max_regions = 20 + count * 7;
        struct fdt_region fdt_regions[max_regions];

        /* Get a list of regions to hash */
        count = fdt_find_regions(fit, node_inc, count,
                                 exc_prop, ARRAY_SIZE(exc_prop),
                                 fdt_regions, max_regions - 1,
                                 path, sizeof(path), 0);
        if (count < 0) {
                *err_msgp = "Failed to hash configuration";
                return -1;
        }
        if (count == 0) {
                *err_msgp = "No data to hash";
                return -1;
        }
        if (count >= max_regions - 1) {
                *err_msgp = "Too many hash regions";
                return -1;
        }

        /* Add the strings */
        strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
        if (strings) {
                /*
                 * The strings region offset must be a static 0x0.
                 * This is set in tool/image-host.c
                 */
                fdt_regions[count].offset = fdt_off_dt_strings(fit);
                fdt_regions[count].size = fdt32_to_cpu(strings[1]);
                count++;
        }

        /* Allocate the region list on the stack */
        struct image_region region[count];

        fit_region_make_list(fit, fdt_regions, count, region);
        if (info.crypto->verify(&info, region, count, fit_value,
                                fit_value_len)) {
                *err_msgp = "Verification failed";
                return -1;
        }

        return 0;
}

/**
 * fit_config_verify_key() - Verify that a configuration is signed with a key
 *
 * Here we are looking at a particular configuration that needs verification:
 *
 *      configurations {
 *              default = "conf-1";
 *              conf-1 {
 *                      kernel = "kernel-1";
 *                      fdt = "fdt-1";
 *                      signature-1 {
 *                              algo = "sha1,rsa2048";
 *                              value = <...conf 1 signature...>;
 *                      };
 *              };
 *
 * We must check each of the signature subnodes of conf-1. Hopefully one of them
 * will match the key at key_offset.
 *
 * @fit: FIT to check
 * @conf_noffset: Offset of the configuration node to check (e.g.
 *      /configurations/conf-1)
 * @key_blob: Blob containing the keys to check against
 * @key_offset: Offset of the key to check within @key_blob
 * @return 0 if OK, -EPERM if any signatures did not verify, or the
 *      configuration node has an invalid name
 */
static int fit_config_verify_key(const void *fit, int conf_noffset,
                                 const void *key_blob, int key_offset)
{
        int noffset;
        char *err_msg = "No 'signature' subnode found";
        int verified = 0;
        int ret;

        /* Process all hash subnodes of the component conf node */
        fdt_for_each_subnode(noffset, fit, conf_noffset) {
                const char *name = fit_get_name(fit, noffset, NULL);

                if (!strncmp(name, FIT_SIG_NODENAME,
                             strlen(FIT_SIG_NODENAME))) {
                        ret = fit_config_check_sig(fit, noffset, conf_noffset,
                                                   key_blob, key_offset,
                                                   &err_msg);
                        if (ret) {
                                puts("- ");
                        } else {
                                puts("+ ");
                                verified = 1;
                                break;
                        }
                }
        }

        if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
                err_msg = "Corrupted or truncated tree";
                goto error;
        }

        if (verified)
                return 0;

error:
        printf(" error!\n%s for '%s' hash node in '%s' config node\n",
               err_msg, fit_get_name(fit, noffset, NULL),
               fit_get_name(fit, conf_noffset, NULL));
        return -EPERM;
}

/**
 * fit_config_verify_required_keys() - verify any required signatures for config
 *
 * This looks through all the signatures we expect and verifies that at least
 * all the required ones are valid signatures for the configuration
 *
 * @fit: FIT to check
 * @conf_noffset: Offset of the configuration node to check (e.g.
 *      /configurations/conf-1)
 * @key_blob: Blob containing the keys to check against
 * @return 0 if OK, -EPERM if any signatures did not verify, or the
 *      configuration node has an invalid name
 */
static int fit_config_verify_required_keys(const void *fit, int conf_noffset,
                                           const void *key_blob)
{
        const char *name = fit_get_name(fit, conf_noffset, NULL);
        int noffset;
        int key_node;
        int verified = 0;
        int reqd_sigs = 0;
        bool reqd_policy_all = true;
        const char *reqd_mode;

        /*
         * We don't support this since libfdt considers names with the
         * name root but different @ suffix to be equal
         */
        if (strchr(name, '@')) {
                printf("Configuration node '%s' contains '@'\n", name);
                return -EPERM;
        }

        /* Work out what we need to verify */
        key_node = fdt_subnode_offset(key_blob, 0, FIT_SIG_NODENAME);
        if (key_node < 0) {
                debug("%s: No signature node found: %s\n", __func__,
                      fdt_strerror(key_node));
                return 0;
        }

        /* 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());
}