From e8aa5580d41dbe556c85a753188de9e43045b220 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Fri, 12 Nov 2021 12:28:08 -0700 Subject: tools: Avoid confusion between keys and signatures We should be consistent in using the term 'signature' to describe a value added to sign something and 'key' to describe the key that can be used to verify the signature. Tidy up the code to stick to this. Add some comments to fit_config_verify_key() and its callers while we are here. Signed-off-by: Simon Glass --- boot/image-fit-sig.c | 97 ++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 72 insertions(+), 25 deletions(-) (limited to 'boot') diff --git a/boot/image-fit-sig.c b/boot/image-fit-sig.c index 495d7768f68..e07bacb77a7 100644 --- a/boot/image-fit-sig.c +++ b/boot/image-fit-sig.c @@ -135,7 +135,7 @@ int fit_image_check_sig(const void *fit, int noffset, const void *data, 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) + const void *key_blob, int key_offset) { int noffset; char *err_msg = ""; @@ -184,34 +184,34 @@ 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) + const void *key_blob, int *no_sigsp) { int verify_count = 0; int noffset; - int sig_node; + int key_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) { + 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(sig_node)); + fdt_strerror(key_node)); return 0; } - fdt_for_each_subnode(noffset, sig_blob, sig_node) { + fdt_for_each_subnode(noffset, key_blob, key_node) { const char *required; int ret; - required = fdt_getprop(sig_blob, noffset, FIT_KEY_REQUIRED, + 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, - sig_blob, noffset); + key_blob, noffset); if (ret) { printf("Failed to verify required signature '%s'\n", - fit_get_name(sig_blob, noffset, NULL)); + fit_get_name(key_blob, noffset, NULL)); return ret; } verify_count++; @@ -368,8 +368,35 @@ static int fit_config_check_sig(const void *fit, int noffset, return 0; } -static int fit_config_verify_sig(const void *fit, int conf_noffset, - const void *sig_blob, int sig_offset) +/** + * 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"; @@ -382,7 +409,7 @@ static int fit_config_verify_sig(const void *fit, int conf_noffset, if (!strncmp(name, FIT_SIG_NODENAME, strlen(FIT_SIG_NODENAME))) { - ret = fit_config_check_sig(fit, noffset, sig_offset, + ret = fit_config_check_sig(fit, noffset, key_offset, conf_noffset, &err_msg); if (ret) { puts("- "); @@ -409,12 +436,25 @@ error: return -EPERM; } -static int fit_config_verify_required_sigs(const void *fit, int conf_noffset, - const void *sig_blob) +/** + * 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 sig_node; + int key_node; int verified = 0; int reqd_sigs = 0; bool reqd_policy_all = true; @@ -430,38 +470,45 @@ static int fit_config_verify_required_sigs(const void *fit, int conf_noffset, } /* Work out what we need to verify */ - sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME); - if (sig_node < 0) { + 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(sig_node)); + fdt_strerror(key_node)); return 0; } /* Get required-mode policy property from DTB */ - reqd_mode = fdt_getprop(sig_blob, sig_node, "required-mode", NULL); + 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"); - fdt_for_each_subnode(noffset, sig_blob, sig_node) { + /* + * 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(sig_blob, noffset, FIT_KEY_REQUIRED, + required = fdt_getprop(key_blob, noffset, FIT_KEY_REQUIRED, NULL); if (!required || strcmp(required, "conf")) continue; reqd_sigs++; - ret = fit_config_verify_sig(fit, conf_noffset, sig_blob, + 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(sig_blob, noffset, NULL)); + fit_get_name(key_blob, noffset, NULL)); return ret; } } else { @@ -481,6 +528,6 @@ static int fit_config_verify_required_sigs(const void *fit, int conf_noffset, int fit_config_verify(const void *fit, int conf_noffset) { - return fit_config_verify_required_sigs(fit, conf_noffset, + return fit_config_verify_required_keys(fit, conf_noffset, gd_fdt_blob()); } -- cgit v1.3.1 From 2ad90b395313a7350cfb0543b4979a24746413b3 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Fri, 12 Nov 2021 12:28:09 -0700 Subject: tools: Tidy up argument order in fit_config_check_sig() Put the parent node first in the parameters as this is more natural. Also add a comment to explain what is going on. Signed-off-by: Simon Glass --- boot/image-fit-sig.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) (limited to 'boot') diff --git a/boot/image-fit-sig.c b/boot/image-fit-sig.c index e07bacb77a7..d6e16c29ed3 100644 --- a/boot/image-fit-sig.c +++ b/boot/image-fit-sig.c @@ -226,21 +226,34 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, /** * 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 configuration node (e.g. /configurations/conf-1) - * @required_keynode: Offset in the control FDT of the required key node, + * @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) + * @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. - * @conf_noffset: Offset of the configuration subnode being checked (e.g. - * /configurations/conf-1/kernel) * @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 required_keynode, int conf_noffset, - char **err_msgp) +static int fit_config_check_sig(const void *fit, int noffset, int conf_noffset, + int required_keynode, char **err_msgp) { static char * const exc_prop[] = { "data", @@ -409,8 +422,8 @@ static int fit_config_verify_key(const void *fit, int conf_noffset, if (!strncmp(name, FIT_SIG_NODENAME, strlen(FIT_SIG_NODENAME))) { - ret = fit_config_check_sig(fit, noffset, key_offset, - conf_noffset, &err_msg); + ret = fit_config_check_sig(fit, noffset, conf_noffset, + key_offset, &err_msg); if (ret) { puts("- "); } else { -- cgit v1.3.1 From 99f844ba3a6b3ddd73742cddf7dee955bbb96c61 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Fri, 12 Nov 2021 12:28:10 -0700 Subject: tools: Pass the key blob around At present we rely on the key blob being in the global_data fdt_blob pointer. This is true in U-Boot but not with tools. For clarity, pass the parameter around. Signed-off-by: Simon Glass --- boot/image-fit-sig.c | 31 ++++++++++++++++++------------- boot/image-fit.c | 12 +++++++----- common/spl/spl_fit.c | 3 ++- include/image.h | 23 ++++++++++++++++++----- 4 files changed, 45 insertions(+), 24 deletions(-) (limited to 'boot') diff --git a/boot/image-fit-sig.c b/boot/image-fit-sig.c index d6e16c29ed3..a461d591a0e 100644 --- a/boot/image-fit-sig.c +++ b/boot/image-fit-sig.c @@ -65,7 +65,8 @@ struct image_region *fit_region_make_list(const void *fit, static int fit_image_setup_verify(struct image_sign_info *info, const void *fit, int noffset, - int required_keynode, char **err_msgp) + const void *key_blob, int required_keynode, + char **err_msgp) { const char *algo_name; const char *padding_name; @@ -91,7 +92,7 @@ static int fit_image_setup_verify(struct image_sign_info *info, 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 = gd_fdt_blob(); + info->fdt_blob = key_blob; info->required_keynode = required_keynode; printf("%s:%s", algo_name, info->keyname); @@ -104,7 +105,8 @@ static int fit_image_setup_verify(struct image_sign_info *info, } int fit_image_check_sig(const void *fit, int noffset, const void *data, - size_t size, int required_keynode, char **err_msgp) + size_t size, const void *key_blob, int required_keynode, + char **err_msgp) { struct image_sign_info info; struct image_region region; @@ -112,8 +114,8 @@ int fit_image_check_sig(const void *fit, int noffset, const void *data, int fit_value_len; *err_msgp = NULL; - if (fit_image_setup_verify(&info, fit, noffset, required_keynode, - err_msgp)) + 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, @@ -156,8 +158,8 @@ static int fit_image_verify_sig(const void *fit, int image_noffset, } if (!strncmp(name, FIT_SIG_NODENAME, strlen(FIT_SIG_NODENAME))) { - ret = fit_image_check_sig(fit, noffset, data, - size, -1, &err_msg); + ret = fit_image_check_sig(fit, noffset, data, size, + key_blob, -1, &err_msg); if (ret) { puts("- "); } else { @@ -244,6 +246,7 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, * @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 @@ -253,7 +256,8 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, * Return: 0 if all verified ok, <0 on error */ static int fit_config_check_sig(const void *fit, int noffset, int conf_noffset, - int required_keynode, char **err_msgp) + const void *key_blob, int required_keynode, + char **err_msgp) { static char * const exc_prop[] = { "data", @@ -275,12 +279,12 @@ static int fit_config_check_sig(const void *fit, int noffset, int conf_noffset, int count; config_name = fit_get_name(fit, conf_noffset, NULL); - debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(), + debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, key_blob, fit_get_name(fit, noffset, NULL), - fit_get_name(gd_fdt_blob(), required_keynode, NULL)); + fit_get_name(key_blob, required_keynode, NULL)); *err_msgp = NULL; - if (fit_image_setup_verify(&info, fit, noffset, required_keynode, - err_msgp)) + 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, @@ -423,7 +427,8 @@ static int fit_config_verify_key(const void *fit, int conf_noffset, if (!strncmp(name, FIT_SIG_NODENAME, strlen(FIT_SIG_NODENAME))) { ret = fit_config_check_sig(fit, noffset, conf_noffset, - key_offset, &err_msg); + key_blob, key_offset, + &err_msg); if (ret) { puts("- "); } else { diff --git a/boot/image-fit.c b/boot/image-fit.c index 85a6f223c85..f01cafe4e27 100644 --- a/boot/image-fit.c +++ b/boot/image-fit.c @@ -1309,7 +1309,8 @@ static int fit_image_check_hash(const void *fit, int noffset, const void *data, } int fit_image_verify_with_data(const void *fit, int image_noffset, - const void *data, size_t size) + const void *key_blob, const void *data, + size_t size) { int noffset = 0; char *err_msg = ""; @@ -1319,7 +1320,7 @@ int fit_image_verify_with_data(const void *fit, int image_noffset, /* Verify all required signatures */ if (FIT_IMAGE_ENABLE_VERIFY && fit_image_verify_required_sigs(fit, image_noffset, data, size, - gd_fdt_blob(), &verify_all)) { + key_blob, &verify_all)) { err_msg = "Unable to verify required signature"; goto error; } @@ -1342,8 +1343,8 @@ int fit_image_verify_with_data(const void *fit, int image_noffset, } else if (FIT_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); + ret = fit_image_check_sig(fit, noffset, data, size, + gd_fdt_blob(), -1, &err_msg); /* * Show an indication on failure, but do not return @@ -1406,7 +1407,8 @@ int fit_image_verify(const void *fit, int image_noffset) goto err; } - return fit_image_verify_with_data(fit, image_noffset, data, size); + return fit_image_verify_with_data(fit, image_noffset, gd_fdt_blob(), + data, size); err: printf("error!\n%s in '%s' image node\n", err_msg, diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c index 774072b85c5..1bbf824684a 100644 --- a/common/spl/spl_fit.c +++ b/common/spl/spl_fit.c @@ -321,7 +321,8 @@ static int spl_load_fit_image(struct spl_load_info *info, ulong sector, if (CONFIG_IS_ENABLED(FIT_SIGNATURE)) { printf("## Checking hash(es) for Image %s ... ", fit_get_name(fit, node, NULL)); - if (!fit_image_verify_with_data(fit, node, src, length)) + if (!fit_image_verify_with_data(fit, node, gd_fdt_blob(), src, + length)) return -EPERM; puts("OK\n"); } diff --git a/include/image.h b/include/image.h index 15cfb2c54b0..780b624c8c9 100644 --- a/include/image.h +++ b/include/image.h @@ -1048,8 +1048,19 @@ int fit_add_verification_data(const char *keydir, const char *keyfile, int require_keys, const char *engine_id, const char *cmdname, const char *algo_name); +/** + * fit_image_verify_with_data() - Verify an image with given data + * + * @fit: Pointer to the FIT format image header + * @image_offset: Offset in @fit of image to verify + * @key_blob: FDT containing public keys + * @data: Image data to verify + * @size: Size of image data + */ int fit_image_verify_with_data(const void *fit, int image_noffset, - const void *data, size_t size); + const void *key_blob, const void *data, + size_t size); + int fit_image_verify(const void *fit, int noffset); int fit_config_verify(const void *fit, int conf_noffset); int fit_all_image_verify(const void *fit); @@ -1297,7 +1308,7 @@ struct padding_algo *image_get_padding_algo(const char *name); * @image_noffset: Offset of image node to check * @data: Image data to check * @size: Size of image data - * @sig_blob: FDT containing public keys + * @key_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 @@ -1305,7 +1316,7 @@ struct padding_algo *image_get_padding_algo(const char *name); * 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, + const char *data, size_t size, const void *key_blob, int *no_sigsp); /** @@ -1315,7 +1326,8 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, * @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, + * @keyblob: Key blob to check (typically the control FDT) + * @required_keynode: Offset in the keyblob 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. @@ -1324,7 +1336,8 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, * 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); + size_t size, const void *key_blob, int required_keynode, + char **err_msgp); int fit_image_decrypt_data(const void *fit, int image_noffset, int cipher_noffset, -- cgit v1.3.1