From efba797b977c99bc6e0c301299272c80fb8b287f Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Fri, 6 May 2016 15:38:17 -0700 Subject: [PATCH] KEYS: Add an optional lookup_restriction hook to key_type The restrict_link functions used to validate keys as they are linked to a keyring can be associated with specific key types. Each key type may be loaded (or not) at runtime, so lookup of restrict_link functions needs to be part of the key type implementation to ensure that the requested keys can be examined. Signed-off-by: Mat Martineau --- Documentation/security/keys.txt | 9 +++++++++ include/linux/key-type.h | 8 ++++++++ 2 files changed, 17 insertions(+) diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt index e35de987fc48..5fe04a7cc03d 100644 --- a/Documentation/security/keys.txt +++ b/Documentation/security/keys.txt @@ -1445,6 +1445,15 @@ The structure has a number of fields, some of which are mandatory: The authorisation key. + (*) struct key_restriction *(*lookup_restriction)(const char *params); + + This optional method is used to enable userspace configuration of keyring + restrictions. The restriction parameter string (not including the key type + name) is passed in, and this method returns a pointer to a key_restriction + structure containing the relevant functions and data to evaluate each + attempted key link operation. If there is no match, -EINVAL is returned. + + ============================ REQUEST-KEY CALLBACK SERVICE ============================ diff --git a/include/linux/key-type.h b/include/linux/key-type.h index eaee981c5558..8496cf64575c 100644 --- a/include/linux/key-type.h +++ b/include/linux/key-type.h @@ -147,6 +147,14 @@ struct key_type { */ request_key_actor_t request_key; + /* Look up a keyring access restriction (optional) + * + * - NULL is a valid return value (meaning the requested restriction + * is known but will never block addition of a key) + * - should return -EINVAL if the restriction is unknown + */ + struct key_restriction *(*lookup_restriction)(const char *params); + /* internal fields */ struct list_head link; /* link in types list */ struct lock_class_key lock_class; /* key->sem lock class */ -- 2.39.5