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author | Mat Martineau <mathew.j.martineau@linux.intel.com> | 2016-05-06 14:25:39 -0700 |
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committer | Mat Martineau <mathew.j.martineau@linux.intel.com> | 2017-04-04 14:10:12 -0700 |
commit | 97d3aa0f313435a24440e7157c9c9115c58ca463 (patch) | |
tree | 56c00ecd720a6b1f9564ec01f5e6a3d8b805c455 | |
parent | 6563c91fd645556c7801748f15bc727c77fcd311 (diff) | |
download | linux-stable-97d3aa0f313435a24440e7157c9c9115c58ca463.tar.gz linux-stable-97d3aa0f313435a24440e7157c9c9115c58ca463.tar.bz2 linux-stable-97d3aa0f313435a24440e7157c9c9115c58ca463.zip |
KEYS: Add a lookup_restriction function for the asymmetric key type
Look up asymmetric keyring restriction information using the key-type
lookup_restrict hook.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
-rw-r--r-- | Documentation/crypto/asymmetric-keys.txt | 35 | ||||
-rw-r--r-- | crypto/asymmetric_keys/asymmetric_type.c | 52 |
2 files changed, 79 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..2e3380d09631 100644 --- a/crypto/asymmetric_keys/asymmetric_type.c +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -17,6 +17,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/ctype.h> +#include <keys/system_keyring.h> #include "asymmetric_keys.h" MODULE_LICENSE("GPL"); @@ -451,15 +452,50 @@ 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, + struct key *key) +{ + struct key_restriction *keyres = + kzalloc(sizeof(struct key_restriction), GFP_KERNEL); + + if (!keyres) + return ERR_PTR(-ENOMEM); + + keyres->check = check; + keyres->key = key; + 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); + + if (strcmp("builtin_and_secondary_trusted", restriction) == 0) + return asymmetric_restriction_alloc( + restrict_link_by_builtin_and_secondary_trusted, 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); |