Add support for signing images using a new signature node. The process is handled by fdt_add_verification_data() which now takes parameters to provide the keys and related information.
Signed-off-by: Simon Glass sjg@chromium.org --- Changes in v2: - Adjust how signing enable works in image.h - Fix FDT error handling in fit_image_write_sig() - Fix checkpatch checks about parenthesis alignment - Fix checkpatch warnings about split strings - Require CONFIG_FIT_SIGNATURE in image.h for mkimage to support signing
common/image-fit.c | 85 ++++++++++++++----- common/image-sig.c | 148 ++++++++++++++++++++++++++++++++ doc/uImage.FIT/sign-images.its | 42 ++++++++++ include/image.h | 59 ++++++++++++- tools/fit_image.c | 2 +- tools/image-host.c | 186 ++++++++++++++++++++++++++++++++++++++--- 6 files changed, 484 insertions(+), 38 deletions(-) create mode 100644 doc/uImage.FIT/sign-images.its
diff --git a/common/image-fit.c b/common/image-fit.c index 5dcb0c6..30790d3 100644 --- a/common/image-fit.c +++ b/common/image-fit.c @@ -31,6 +31,8 @@ #include <time.h> #else #include <common.h> +#include <errno.h> +DECLARE_GLOBAL_DATA_PTR; #endif /* !USE_HOSTCC*/
#include <bootstage.h> @@ -233,42 +235,45 @@ void fit_print_contents(const void *fit) * @fit: pointer to the FIT format image header * @noffset: offset of the hash node * @p: pointer to prefix string + * @type: Type of information to print ("hash" or "sign") * * fit_image_print_data() lists properies for the processed hash node * + * This function avoid using puts() since it prints a newline on the host + * but does not in U-Boot. + * * returns: * no returned results */ -static void fit_image_print_data(const void *fit, int noffset, const char *p) +static void fit_image_print_data(const void *fit, int noffset, const char *p, + const char *type) { - char *algo; + const char *keyname; uint8_t *value; int value_len; - int i, ret; - - /* - * Check subnode name, must be equal to "hash". - * Multiple hash nodes require unique unit node - * names, e.g. hash@1, hash@2, etc. - */ - if (strncmp(fit_get_name(fit, noffset, NULL), - FIT_HASH_NODENAME, - strlen(FIT_HASH_NODENAME)) != 0) - return; + char *algo; + int required; + int ret, i;
- debug("%s Hash node: '%s'\n", p, + debug("%s %s node: '%s'\n", p, type, fit_get_name(fit, noffset, NULL)); - - printf("%s Hash algo: ", p); + printf("%s %s algo: ", p, type); if (fit_image_hash_get_algo(fit, noffset, &algo)) { printf("invalid/unsupported\n"); return; } - printf("%s\n", algo); + printf("%s", algo); + keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL); + required = fdt_getprop(fit, noffset, "required", NULL) != NULL; + if (keyname) + printf(":%s", keyname); + if (required) + printf(" (required)"); + printf("\n");
ret = fit_image_hash_get_value(fit, noffset, &value, &value_len); - printf("%s Hash value: ", p); + printf("%s %s value: ", p, type); if (ret) { printf("unavailable\n"); } else { @@ -277,7 +282,18 @@ static void fit_image_print_data(const void *fit, int noffset, const char *p) printf("\n"); }
- debug("%s Hash len: %d\n", p, value_len); + debug("%s %s len: %d\n", p, type, value_len); + + /* Signatures have a time stamp */ + if (IMAGE_ENABLE_TIMESTAMP && keyname) { + time_t timestamp; + + printf("%s Timestamp: ", p); + if (fit_get_timestamp(fit, noffset, ×tamp)) + printf("unavailable\n"); + else + genimg_print_time(timestamp); + } }
/** @@ -302,8 +318,12 @@ static void fit_image_print_verification_data(const void *fit, int noffset, * names, e.g. hash@1, hash@2, signature@1, signature@2, etc. */ name = fit_get_name(fit, noffset, NULL); - if (!strncmp(name, FIT_HASH_NODENAME, strlen(FIT_HASH_NODENAME))) - fit_image_print_data(fit, noffset, p); + if (!strncmp(name, FIT_HASH_NODENAME, strlen(FIT_HASH_NODENAME))) { + fit_image_print_data(fit, noffset, p, "Hash"); + } else if (!strncmp(name, FIT_SIG_NODENAME, + strlen(FIT_SIG_NODENAME))) { + fit_image_print_data(fit, noffset, p, "Sign"); + } }
/** @@ -939,14 +959,24 @@ int fit_image_verify(const void *fit, int image_noffset) { const void *data; size_t size; - int noffset; + int noffset = 0; int ndepth; char *err_msg = ""; + int verify_all = 1; + int ret;
/* Get image data and data length */ if (fit_image_get_data(fit, image_noffset, &data, &size)) { err_msg = "Can't get image data/size"; - return 0; + goto error; + } + + /* Verify all required signatures */ + if (IMAGE_ENABLE_VERIFY && + fit_image_verify_required_sigs(fit, image_noffset, data, size, + gd_fdt_blob(), &verify_all)) { + err_msg = "Unable to verify required signature"; + goto error; }
/* Process all hash subnodes of the component image node */ @@ -967,6 +997,15 @@ int fit_image_verify(const void *fit, int image_noffset) &err_msg)) goto error; puts("+ "); + } else if (IMAGE_ENABLE_VERIFY && verify_all && + !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("+ "); } }
diff --git a/common/image-sig.c b/common/image-sig.c index 841c662..1401c75 100644 --- a/common/image-sig.c +++ b/common/image-sig.c @@ -22,6 +22,8 @@ #include <time.h> #else #include <common.h> +#include <malloc.h> +DECLARE_GLOBAL_DATA_PTR; #endif /* !USE_HOSTCC*/ #include <errno.h> #include <image.h> @@ -40,3 +42,149 @@ struct image_sig_algo *image_get_sig_algo(const char *name)
return NULL; } + +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; + int ndepth; + char *err_msg = ""; + int verified = 0; + int ret; + + /* Process all hash subnodes of the component image node */ + for (ndepth = 0, + noffset = fdt_next_subnode(fit, image_noffset, &ndepth); + noffset >= 0; + noffset = fdt_next_subnode(fit, noffset, &ndepth)) { + 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 ndepth, 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 (ndepth = 0, noffset = fdt_next_subnode(sig_blob, sig_node, + &ndepth); + noffset >= 0; + noffset = fdt_next_subnode(sig_blob, noffset, + &ndepth)) { + 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; +} diff --git a/doc/uImage.FIT/sign-images.its b/doc/uImage.FIT/sign-images.its new file mode 100644 index 0000000..f69326a --- /dev/null +++ b/doc/uImage.FIT/sign-images.its @@ -0,0 +1,42 @@ +/dts-v1/; + +/ { + description = "Chrome OS kernel image with one or more FDT blobs"; + #address-cells = <1>; + + images { + kernel@1 { + data = /incbin/("test-kernel.bin"); + type = "kernel_noload"; + arch = "sandbox"; + os = "linux"; + compression = "none"; + load = <0x4>; + entry = <0x8>; + kernel-version = <1>; + signature@1 { + algo = "sha1,rsa2048"; + key-name-hint = "dev"; + }; + }; + fdt@1 { + description = "snow"; + data = /incbin/("sandbox-kernel.dtb"); + type = "flat_dt"; + arch = "sandbox"; + compression = "none"; + fdt-version = <1>; + signature@1 { + algo = "sha1,rsa2048"; + key-name-hint = "dev"; + }; + }; + }; + configurations { + default = "conf@1"; + conf@1 { + kernel = "kernel@1"; + fdt = "fdt@1"; + }; + }; +}; diff --git a/include/image.h b/include/image.h index 695473a..99015cd 100644 --- a/include/image.h +++ b/include/image.h @@ -618,12 +618,26 @@ int fit_image_hash_get_value(const void *fit, int noffset, uint8_t **value, int fit_set_timestamp(void *fit, int noffset, time_t timestamp);
/** - * fit_add_verification_data() - Calculate and add hashes to FIT + * fit_add_verification_data() - add verification data to FIT image nodes * - * @fit: Fit image to process - * @return 0 if ok, <0 for error + * @keydir: Directory containing keys + * @kwydest: FDT blob to write public key information to + * @fit: Pointer to the FIT format image header + * @comment: Comment to add to signature nodes + * @require_keys: Mark all keys as 'required' + * + * Adds hash values for all component images in the FIT blob. + * Hashes are calculated for all component images which have hash subnodes + * with algorithm property set to one of the supported hash algorithms. + * + * Also add signatures if signature nodes are present. + * + * returns + * 0, on success + * libfdt error code, on failure */ -int fit_add_verification_data(void *fit); +int fit_add_verification_data(const char *keydir, void *keydest, void *fit, + const char *comment, int require_keys);
int fit_image_verify(const void *fit, int noffset); int fit_all_image_verify(const void *fit); @@ -762,6 +776,43 @@ struct image_sig_algo { */ struct image_sig_algo *image_get_sig_algo(const char *name);
+/** + * fit_image_verify_required_sigs() - Verify signatures marked as 'required' + * + * @fit: FIT to check + * @image_noffset: Offset of image node to check + * @data: Image data to check + * @size: Size of image data + * @sig_blob: FDT containing public keys + * @no_sigsp: Returns 1 if no signatures were required, and + * therefore nothing was checked. The caller may wish + * to fall back to other mechanisms, or refuse to + * boot. + * @return 0 if all verified ok, <0 on error + */ +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); + +/** + * fit_image_check_sig() - Check a single image signature node + * + * @fit: FIT to check + * @noffset: Offset of signature node to check + * @data: Image data to check + * @size: Size of image data + * @required_keynode: Offset in the control FDT of the required key node, + * if any. If this is given, then the image 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 + */ +int fit_image_check_sig(const void *fit, int noffset, const void *data, + size_t size, int required_keynode, char **err_msgp); + + #ifndef USE_HOSTCC static inline int fit_image_check_target_arch(const void *fdt, int node) { diff --git a/tools/fit_image.c b/tools/fit_image.c index 8f51159..e0675d7 100644 --- a/tools/fit_image.c +++ b/tools/fit_image.c @@ -125,7 +125,7 @@ static int fit_handle_file (struct mkimage_params *params) }
/* set hashes for images in the blob */ - if (fit_add_verification_data(ptr)) { + if (fit_add_verification_data(NULL, NULL, ptr, NULL, 0)) { fprintf (stderr, "%s Can't add hashes to FIT blob", params->cmdname); unlink (tmpfile); diff --git a/tools/image-host.c b/tools/image-host.c index 3ba05de..2836881 100644 --- a/tools/image-host.c +++ b/tools/image-host.c @@ -26,12 +26,8 @@ */
#include "mkimage.h" -#include <bootstage.h> #include <image.h> -#include <sha1.h> -#include <time.h> -#include <u-boot/crc.h> -#include <u-boot/md5.h> +#include <version.h>
/** * fit_set_hash_value - set hash value in requested has node @@ -108,9 +104,165 @@ static int fit_image_process_hash(void *fit, const char *image_name, }
/** - * fit_image_add_verification_data() - calculate/set hash data for image node + * fit_image_write_sig() - write the signature to a FIT * - * This adds hash values for a component image node. + * This writes the signature and signer data to the FIT. + * + * @fit: pointer to the FIT format image header + * @noffset: hash node offset + * @value: signature value to be set + * @value_len: signature value length + * @comment: Text comment to write (NULL for none) + * + * returns + * 0, on success + * -FDT_ERR_..., on failure + */ +static int fit_image_write_sig(void *fit, int noffset, uint8_t *value, + int value_len, const char *comment, const char *region_prop, + int region_proplen) +{ + int string_size; + int ret; + + /* + * Get the current string size, before we update the FIT and add + * more + */ + string_size = fdt_size_dt_strings(fit); + + ret = fdt_setprop(fit, noffset, FIT_VALUE_PROP, value, value_len); + if (!ret) { + ret = fdt_setprop_string(fit, noffset, "signer-name", + "mkimage"); + } + if (!ret) { + ret = fdt_setprop_string(fit, noffset, "signer-version", + PLAIN_VERSION); + } + if (comment && !ret) + ret = fdt_setprop_string(fit, noffset, "comment", comment); + if (!ret) + ret = fit_set_timestamp(fit, noffset, time(NULL)); + if (region_prop && !ret) { + uint32_t strdata[2]; + + ret = fdt_setprop(fit, noffset, "hashed-nodes", + region_prop, region_proplen); + strdata[0] = 0; + strdata[1] = cpu_to_fdt32(string_size); + if (!ret) { + ret = fdt_setprop(fit, noffset, "hashed-strings", + strdata, sizeof(strdata)); + } + } + + return ret; +} + +static int fit_image_setup_sig(struct image_sign_info *info, + const char *keydir, void *fit, const char *image_name, + int noffset, const char *require_keys) +{ + const char *node_name; + char *algo_name; + + node_name = fit_get_name(fit, noffset, NULL); + if (fit_image_hash_get_algo(fit, noffset, &algo_name)) { + printf("Can't get algo property for '%s' signature node in '%s' image node\n", + node_name, image_name); + return -1; + } + + memset(info, '\0', sizeof(*info)); + info->keydir = keydir; + info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL); + info->fit = fit; + info->node_offset = noffset; + info->algo = image_get_sig_algo(algo_name); + info->require_keys = require_keys; + if (!info->algo) { + printf("Unsupported signature algorithm (%s) for '%s' signature node in '%s' image node\n", + algo_name, node_name, image_name); + return -1; + } + + return 0; +} + +/** + * fit_image_process_sig- Process a single subnode of the images/ node + * + * Check each subnode and process accordingly. For signature nodes we + * generate a signed hash of the supplised data and store it in the node. + * + * @keydir: Directory containing keys to use for signing + * @keydest: Destination FDT blob to write public keys into + * @fit: pointer to the FIT format image header + * @image_name: name of image being processes (used to display errors) + * @noffset: subnode offset + * @data: data to process + * @size: size of data in bytes + * @comment: Comment to add to signature nodes + * @require_keys: Mark all keys as 'required' + * @return 0 if ok, -1 on error + */ +static int fit_image_process_sig(const char *keydir, void *keydest, + void *fit, const char *image_name, + int noffset, const void *data, size_t size, + const char *comment, int require_keys) +{ + struct image_sign_info info; + struct image_region region; + const char *node_name; + uint8_t *value; + uint value_len; + int ret; + + if (fit_image_setup_sig(&info, keydir, fit, image_name, noffset, + require_keys ? "image" : NULL)) + return -1; + + node_name = fit_get_name(fit, noffset, NULL); + region.data = data; + region.size = size; + ret = info.algo->sign(&info, ®ion, 1, &value, &value_len); + if (ret) { + printf("Failed to sign '%s' signature node in '%s' image node: %d\n", + node_name, image_name, ret); + + /* We allow keys to be missing */ + if (ret == -ENOENT) + return 0; + return -1; + } + + ret = fit_image_write_sig(fit, noffset, value, value_len, comment, + NULL, 0); + if (ret) { + printf("Can't write signature for '%s' signature node in '%s' image node: %s\n", + node_name, image_name, fdt_strerror(ret)); + return -1; + } + free(value); + + /* Get keyname again, as FDT has changed and invalidated our pointer */ + info.keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL); + + /* Write the public key into the supplied FDT file */ + if (keydest && info.algo->add_verify_data(&info, keydest)) { + printf("Failed to add verification data for '%s' signature node in '%s' image node\n", + node_name, image_name); + return -1; + } + + return 0; +} + +/** + * fit_image_add_verification_data() - calculate/set verig. data for image node + * + * This adds hash and signature values for an component image node. * * All existing hash subnodes are checked, if algorithm property is set to * one of the supported hash algorithms, hash value is computed and @@ -133,11 +285,17 @@ static int fit_image_process_hash(void *fit, const char *image_name, * * For signature details, please see doc/uImage.FIT/signature.txt * + * @keydir Directory containing *.key and *.crt files (or NULL) + * @keydest FDT Blob to write public keys into (NULL if none) * @fit: Pointer to the FIT format image header * @image_noffset: Requested component image node + * @comment: Comment to add to signature nodes + * @require_keys: Mark all keys as 'required' * @return: 0 on success, <0 on failure */ -int fit_image_add_verification_data(void *fit, int image_noffset) +int fit_image_add_verification_data(const char *keydir, void *keydest, + void *fit, int image_noffset, const char *comment, + int require_keys) { const char *image_name; const void *data; @@ -171,6 +329,12 @@ int fit_image_add_verification_data(void *fit, int image_noffset) strlen(FIT_HASH_NODENAME))) { ret = fit_image_process_hash(fit, image_name, noffset, data, size); + } else if (IMAGE_ENABLE_SIGN && keydir && + !strncmp(node_name, FIT_SIG_NODENAME, + strlen(FIT_SIG_NODENAME))) { + ret = fit_image_process_sig(keydir, keydest, + fit, image_name, noffset, data, size, + comment, require_keys); } if (ret) return -1; @@ -179,7 +343,8 @@ int fit_image_add_verification_data(void *fit, int image_noffset) return 0; }
-int fit_add_verification_data(void *fit) +int fit_add_verification_data(const char *keydir, void *keydest, void *fit, + const char *comment, int require_keys) { int images_noffset; int noffset; @@ -204,7 +369,8 @@ int fit_add_verification_data(void *fit) * Direct child node of the images parent node, * i.e. component image node. */ - ret = fit_image_add_verification_data(fit, noffset); + ret = fit_image_add_verification_data(keydir, keydest, + fit, noffset, comment, require_keys); if (ret) return ret; }