diff options
Diffstat (limited to 'common/image-sig.c')
| -rw-r--r-- | common/image-sig.c | 422 |
1 files changed, 422 insertions, 0 deletions
diff --git a/common/image-sig.c b/common/image-sig.c new file mode 100644 index 0000000..5d907cf --- /dev/null +++ b/common/image-sig.c @@ -0,0 +1,422 @@ +/* + * Copyright (c) 2013, Google Inc. + * + * 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#ifdef USE_HOSTCC +#include "mkimage.h" +#include <time.h> +#else +#include <common.h> +#include <malloc.h> +DECLARE_GLOBAL_DATA_PTR; +#endif /* !USE_HOSTCC*/ +#include <image.h> +#include <rsa.h> + +#define IMAGE_MAX_HASHED_NODES 100 + +struct image_sig_algo image_sig_algos[] = { + { + "sha1,rsa2048", + rsa_sign, + rsa_add_verify_data, + rsa_verify, + } +}; + +struct image_sig_algo *image_get_sig_algo(const char *name) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(image_sig_algos); i++) { + if (!strcmp(image_sig_algos[i].name, name)) + return &image_sig_algos[i]; + } + + return NULL; +} + +/** + * 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. + */ +#ifndef CONFIG_SPL_BUILD + if (!region) + region = calloc(sizeof(*region), count); +#endif + 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, int required_keynode, + char **err_msgp) +{ + char *algo_name; + + if (fit_image_hash_get_algo(fit, noffset, &algo_name)) { + *err_msgp = "Can't get hash algo property"; + return -1; + } + memset(info, '\0', sizeof(*info)); + info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL); + info->fit = (void *)fit; + info->node_offset = noffset; + info->algo = image_get_sig_algo(algo_name); + info->fdt_blob = gd_fdt_blob(); + info->required_keynode = required_keynode; + printf("%s:%s", algo_name, info->keyname); + + if (!info->algo) { + *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, 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, 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.algo->verify(&info, ®ion, 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 *sig_blob, + int sig_offset) +{ + int noffset; + char *err_msg = ""; + int verified = 0; + int ret; + + /* Process all hash subnodes of the component image node */ + for (noffset = fdt_first_subnode(fit, image_noffset); + noffset >= 0; + noffset = fdt_next_subnode(fit, noffset)) { + const char *name = fit_get_name(fit, noffset, NULL); + + if (!strncmp(name, FIT_SIG_NODENAME, + strlen(FIT_SIG_NODENAME))) { + ret = fit_image_check_sig(fit, noffset, data, + size, -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 *sig_blob, + int *no_sigsp) +{ + int verify_count = 0; + int noffset; + int sig_node; + + /* Work out what we need to verify */ + *no_sigsp = 1; + sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME); + if (sig_node < 0) { + debug("%s: No signature node found: %s\n", __func__, + fdt_strerror(sig_node)); + return 0; + } + + for (noffset = fdt_first_subnode(sig_blob, sig_node); + noffset >= 0; + noffset = fdt_next_subnode(sig_blob, noffset)) { + const char *required; + int ret; + + required = fdt_getprop(sig_blob, noffset, "required", NULL); + if (!required || strcmp(required, "image")) + continue; + ret = fit_image_verify_sig(fit, image_noffset, data, size, + sig_blob, noffset); + if (ret) { + printf("Failed to verify required signature '%s'\n", + fit_get_name(sig_blob, noffset, NULL)); + return ret; + } + verify_count++; + } + + if (verify_count) + *no_sigsp = 0; + + return 0; +} + +int fit_config_check_sig(const void *fit, int noffset, int required_keynode, + char **err_msgp) +{ + char * const exc_prop[] = {"data"}; + const char *prop, *end, *name; + struct image_sign_info info; + const uint32_t *strings; + uint8_t *fit_value; + int fit_value_len; + int max_regions; + int i, prop_len; + char path[200]; + int count; + + debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(), + fit_get_name(fit, noffset, NULL), + fit_get_name(gd_fdt_blob(), required_keynode, NULL)); + *err_msgp = NULL; + if (fit_image_setup_verify(&info, fit, noffset, 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; + } + + /* 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); + for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) { + debug(" '%s'\n", name); + node_inc[i] = (char *)name; + } + + /* + * 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) { + fdt_regions[count].offset = fdt_off_dt_strings(fit) + + fdt32_to_cpu(strings[0]); + 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.algo->verify(&info, region, count, fit_value, + fit_value_len)) { + *err_msgp = "Verification failed"; + return -1; + } + + return 0; +} + +static int fit_config_verify_sig(const void *fit, int conf_noffset, + const void *sig_blob, int sig_offset) +{ + int noffset; + char *err_msg = ""; + int verified = 0; + int ret; + + /* Process all hash subnodes of the component conf node */ + for (noffset = fdt_first_subnode(fit, conf_noffset); + noffset >= 0; + noffset = fdt_next_subnode(fit, 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, sig_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; + } + + return verified ? 0 : -EPERM; + +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 -1; +} + +int fit_config_verify_required_sigs(const void *fit, int conf_noffset, + const void *sig_blob) +{ + int noffset; + int sig_node; + + /* Work out what we need to verify */ + sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME); + if (sig_node < 0) { + debug("%s: No signature node found: %s\n", __func__, + fdt_strerror(sig_node)); + return 0; + } + + for (noffset = fdt_first_subnode(sig_blob, sig_node); + noffset >= 0; + noffset = fdt_next_subnode(sig_blob, noffset)) { + const char *required; + int ret; + + required = fdt_getprop(sig_blob, noffset, "required", NULL); + if (!required || strcmp(required, "conf")) + continue; + ret = fit_config_verify_sig(fit, conf_noffset, sig_blob, + noffset); + if (ret) { + printf("Failed to verify required signature '%s'\n", + fit_get_name(sig_blob, noffset, NULL)); + return ret; + } + } + + return 0; +} + +int fit_config_verify(const void *fit, int conf_noffset) +{ + return !fit_config_verify_required_sigs(fit, conf_noffset, + gd_fdt_blob()); +} |