From aaf66c883813f0078e3dafe7d20d1461321ac14f Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Tue, 30 Aug 2016 11:33:13 -0700 Subject: [PATCH] KEYS: Split role of the keyring pointer for keyring restrict functions The first argument to the restrict_link_func_t functions was a keyring pointer. These functions are called by the key subsystem with this argument set to the destination keyring, but restrict_link_by_signature expects a pointer to the relevant trusted keyring. Restrict functions may need something other than a single struct key pointer to allow or reject key linkage, so the data used to make that decision (such as the trust keyring) is moved to a new, fourth argument. The first argument is now always the destination keyring. Signed-off-by: Mat Martineau --- Documentation/security/keys.txt | 8 ++++---- certs/system_keyring.c | 18 +++++++++++------- crypto/asymmetric_keys/restrict.c | 8 +++++--- include/crypto/public_key.h | 5 +++-- include/keys/system_keyring.h | 6 ++++-- include/linux/key.h | 8 +++++--- security/keys/key.c | 5 +++-- security/keys/keyring.c | 6 ++++-- 8 files changed, 39 insertions(+), 25 deletions(-) diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt index 4502237b12a7..bb575ab80207 100644 --- a/Documentation/security/keys.txt +++ b/Documentation/security/keys.txt @@ -1054,10 +1054,10 @@ payload contents" for more information. can be verified by a key the kernel already has. When called, the restriction function will be passed the keyring being - added to, the key flags value and the type and payload of the key being - added. Note that when a new key is being created, this is called between - payload preparsing and actual key creation. The function should return 0 - to allow the link or an error to reject it. + added to, the key type, the payload of the key being added, and data to be + used in the restriction check. Note that when a new key is being created, + this is called between payload preparsing and actual key creation. The + function should return 0 to allow the link or an error to reject it. A convenience function, restrict_link_reject, exists to always return -EPERM to in this case. diff --git a/certs/system_keyring.c b/certs/system_keyring.c index 50979d6dcecd..e39cce68dcfa 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -32,11 +32,13 @@ extern __initconst const unsigned long system_certificate_list_size; * Restrict the addition of keys into a keyring based on the key-to-be-added * being vouched for by a key in the built in system keyring. */ -int restrict_link_by_builtin_trusted(struct key *keyring, +int restrict_link_by_builtin_trusted(struct key *dest_keyring, const struct key_type *type, - const union key_payload *payload) + const union key_payload *payload, + struct key *restriction_key) { - return restrict_link_by_signature(builtin_trusted_keys, type, payload); + return restrict_link_by_signature(dest_keyring, type, payload, + builtin_trusted_keys); } #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING @@ -49,20 +51,22 @@ int restrict_link_by_builtin_trusted(struct key *keyring, * keyrings. */ int restrict_link_by_builtin_and_secondary_trusted( - struct key *keyring, + struct key *dest_keyring, const struct key_type *type, - const union key_payload *payload) + const union key_payload *payload, + struct key *restrict_key) { /* If we have a secondary trusted keyring, then that contains a link * through to the builtin keyring and the search will follow that link. */ if (type == &key_type_keyring && - keyring == secondary_trusted_keys && + dest_keyring == secondary_trusted_keys && payload == &builtin_trusted_keys->payload) /* Allow the builtin keyring to be added to the secondary */ return 0; - return restrict_link_by_signature(secondary_trusted_keys, type, payload); + return restrict_link_by_signature(dest_keyring, type, payload, + secondary_trusted_keys); } #endif diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c index 19d1afb9890f..a3afbf783255 100644 --- a/crypto/asymmetric_keys/restrict.c +++ b/crypto/asymmetric_keys/restrict.c @@ -56,9 +56,10 @@ __setup("ca_keys=", ca_keys_setup); /** * restrict_link_by_signature - Restrict additions to a ring of public keys - * @trust_keyring: A ring of keys that can be used to vouch for the new cert. + * @dest_keyring: Keyring being linked to. * @type: The type of key being added. * @payload: The payload of the new key. + * @trust_keyring: A ring of keys that can be used to vouch for the new cert. * * Check the new certificate against the ones in the trust keyring. If one of * those is the signing key and validates the new certificate, then mark the @@ -69,9 +70,10 @@ __setup("ca_keys=", ca_keys_setup); * signature check fails or the key is blacklisted and some other error if * there is a matching certificate but the signature check cannot be performed. */ -int restrict_link_by_signature(struct key *trust_keyring, +int restrict_link_by_signature(struct key *dest_keyring, const struct key_type *type, - const union key_payload *payload) + const union key_payload *payload, + struct key *trust_keyring) { const struct public_key_signature *sig; struct key *key; diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h index 882ca0e1e7a5..ec0262fa08f8 100644 --- a/include/crypto/public_key.h +++ b/include/crypto/public_key.h @@ -50,9 +50,10 @@ struct key; struct key_type; union key_payload; -extern int restrict_link_by_signature(struct key *trust_keyring, +extern int restrict_link_by_signature(struct key *dest_keyring, const struct key_type *type, - const union key_payload *payload); + const union key_payload *payload, + struct key *trust_keyring); extern int verify_signature(const struct key *key, const struct public_key_signature *sig); diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h index 0d8762622ab9..359c2f936004 100644 --- a/include/keys/system_keyring.h +++ b/include/keys/system_keyring.h @@ -18,7 +18,8 @@ extern int restrict_link_by_builtin_trusted(struct key *keyring, const struct key_type *type, - const union key_payload *payload); + const union key_payload *payload, + struct key *restriction_key); #else #define restrict_link_by_builtin_trusted restrict_link_reject @@ -28,7 +29,8 @@ extern int restrict_link_by_builtin_trusted(struct key *keyring, extern int restrict_link_by_builtin_and_secondary_trusted( struct key *keyring, const struct key_type *type, - const union key_payload *payload); + const union key_payload *payload, + struct key *restriction_key); #else #define restrict_link_by_builtin_and_secondary_trusted restrict_link_by_builtin_trusted #endif diff --git a/include/linux/key.h b/include/linux/key.h index 3bb327043869..c59d1008c4fc 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -127,9 +127,10 @@ static inline bool is_key_possessed(const key_ref_t key_ref) return (unsigned long) key_ref & 1UL; } -typedef int (*key_restrict_link_func_t)(struct key *keyring, +typedef int (*key_restrict_link_func_t)(struct key *dest_keyring, const struct key_type *type, - const union key_payload *payload); + const union key_payload *payload, + struct key *restriction_key); /*****************************************************************************/ /* @@ -309,7 +310,8 @@ extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid extern int restrict_link_reject(struct key *keyring, const struct key_type *type, - const union key_payload *payload); + const union key_payload *payload, + struct key *restriction_key); extern int keyring_clear(struct key *keyring); diff --git a/security/keys/key.c b/security/keys/key.c index 08dfa13f6a85..27fc1bb40034 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -499,7 +499,7 @@ int key_instantiate_and_link(struct key *key, if (keyring) { if (keyring->restrict_link) { ret = keyring->restrict_link(keyring, key->type, - &prep.payload); + &prep.payload, NULL); if (ret < 0) goto error; } @@ -851,7 +851,8 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, index_key.desc_len = strlen(index_key.description); if (restrict_link) { - ret = restrict_link(keyring, index_key.type, &prep.payload); + ret = restrict_link(keyring, index_key.type, &prep.payload, + NULL); if (ret < 0) { key_ref = ERR_PTR(ret); goto error_free_prep; diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 1b29ac759bf7..2ccc66ec35d7 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -517,6 +517,7 @@ EXPORT_SYMBOL(keyring_alloc); * @keyring: The keyring being added to. * @type: The type of key being added. * @payload: The payload of the key intended to be added. + * @data: Additional data for evaluating restriction. * * Reject the addition of any links to a keyring. It can be overridden by * passing KEY_ALLOC_BYPASS_RESTRICTION to key_instantiate_and_link() when @@ -527,7 +528,8 @@ EXPORT_SYMBOL(keyring_alloc); */ int restrict_link_reject(struct key *keyring, const struct key_type *type, - const union key_payload *payload) + const union key_payload *payload, + struct key *restriction_key) { return -EPERM; } @@ -1220,7 +1222,7 @@ static int __key_link_check_restriction(struct key *keyring, struct key *key) { if (!keyring->restrict_link) return 0; - return keyring->restrict_link(keyring, key->type, &key->payload); + return keyring->restrict_link(keyring, key->type, &key->payload, NULL); } /**