From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathew.j.martineau@linux.intel.com (Mat Martineau) Date: Thu, 9 Mar 2017 12:23:13 -0800 Subject: [PATCH v12 08/10] KEYS: Add a lookup_restriction function for the asymmetric key type In-Reply-To: <20170309202315.15361-1-mathew.j.martineau@linux.intel.com> References: <20170309202315.15361-1-mathew.j.martineau@linux.intel.com> Message-ID: <20170309202315.15361-9-mathew.j.martineau@linux.intel.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org Look up asymmetric keyring restriction information using the key-type lookup_restrict hook. Signed-off-by: Mat Martineau --- Documentation/crypto/asymmetric-keys.txt | 35 +++++++++++++++++++ crypto/asymmetric_keys/asymmetric_type.c | 59 +++++++++++++++++++++++++++----- 2 files changed, 86 insertions(+), 8 deletions(-) diff --git a/Documentation/crypto/asymmetric-keys.txt b/Documentation/crypto/asymmetric-keys.txt index 2b7816dea370..4373e7d86c6a 100644 --- a/Documentation/crypto/asymmetric-keys.txt +++ b/Documentation/crypto/asymmetric-keys.txt @@ -311,3 +311,38 @@ Functions are provided to register and unregister parsers: Parsers may not have the same name. The names are otherwise only used for displaying in debugging messages. + + +========================= +KEYRING LINK RESTRICTIONS +========================= + +Keyrings created from userspace using add_key can be configured to check the +signature of the key being linked. + +Several restriction methods are available: + + (1) Restrict using the kernel builtin trusted keyring + + - Option string used with KEYCTL_RESTRICT_KEYRING: + - "builtin_trusted" + + The kernel builtin trusted keyring will be searched for the signing + key. The ca_keys kernel parameter also affects which keys are used for + signature verification. + + (2) Restrict using the kernel builtin and secondary trusted keyrings + + - Option string used with KEYCTL_RESTRICT_KEYRING: + - "builtin_and_secondary_trusted" + + The kernel builtin and secondary trusted keyrings will be searched for the + signing key. The ca_keys kernel parameter also affects which keys are used + for signature verification. + +In all of these cases, if the signing key is found the signature of the key to +be linked will be verified using the signing key. The requested key is added +to the keyring only if the signature is successfully verified. -ENOKEY is +returned if the parent certificate could not be found, or -EKEYREJECTED is +returned if the signature check fails or the key is blacklisted. Other errors +may be returned if the signature check could not be performed. diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c index 6600181d5d01..39708253defc 100644 --- a/crypto/asymmetric_keys/asymmetric_type.c +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -17,6 +17,7 @@ #include #include #include +#include #include "asymmetric_keys.h" MODULE_LICENSE("GPL"); @@ -451,15 +452,57 @@ static void asymmetric_key_destroy(struct key *key) asymmetric_key_free_kids(kids); } +static struct key_restriction *asymmetric_restriction_alloc( + key_restrict_link_func_t check, + void (*free_data)(void *), + void *data) +{ + struct key_restriction *keyres = + kzalloc(sizeof(struct key_restriction), GFP_KERNEL); + + if (!keyres) { + if (free_data) + free_data(data); + + return ERR_PTR(-ENOMEM); + } + + keyres->check = check; + keyres->free_data = free_data; + keyres->data = data; + keyres->keytype = &key_type_asymmetric; + + return keyres; +} + +/* + * look up keyring restrict functions for asymmetric keys + */ +static struct key_restriction *asymmetric_lookup_restriction( + const char *restriction) +{ + if (strcmp("builtin_trusted", restriction) == 0) + return asymmetric_restriction_alloc( + restrict_link_by_builtin_trusted, NULL, NULL); + + if (strcmp("builtin_and_secondary_trusted", restriction) == 0) + return asymmetric_restriction_alloc( + restrict_link_by_builtin_and_secondary_trusted, + NULL, NULL); + + return ERR_PTR(-EINVAL); +} + struct key_type key_type_asymmetric = { - .name = "asymmetric", - .preparse = asymmetric_key_preparse, - .free_preparse = asymmetric_key_free_preparse, - .instantiate = generic_key_instantiate, - .match_preparse = asymmetric_key_match_preparse, - .match_free = asymmetric_key_match_free, - .destroy = asymmetric_key_destroy, - .describe = asymmetric_key_describe, + .name = "asymmetric", + .preparse = asymmetric_key_preparse, + .free_preparse = asymmetric_key_free_preparse, + .instantiate = generic_key_instantiate, + .match_preparse = asymmetric_key_match_preparse, + .match_free = asymmetric_key_match_free, + .destroy = asymmetric_key_destroy, + .describe = asymmetric_key_describe, + .lookup_restriction = asymmetric_lookup_restriction, }; EXPORT_SYMBOL_GPL(key_type_asymmetric); -- 2.12.0 -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html