[PATCH v12 05/10] KEYS: Add an optional lookup_restriction hook to key_type
From: Mat Martineau <hidden>
Date: 2017-03-09 20:23:10
Subsystem:
documentation, keys/keyrings, the rest · Maintainers:
Jonathan Corbet, David Howells, Jarkko Sakkinen, Linus Torvalds
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 <redacted> --- Documentation/security/keys.txt | 9 +++++++++ include/linux/key-type.h | 9 +++++++++ 2 files changed, 18 insertions(+)
diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt
index a31b7af8f5cf..18d54fbc9129 100644
--- a/Documentation/security/keys.txt
+++ b/Documentation/security/keys.txt@@ -1433,6 +1433,15 @@ 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..0a0b4c61e829 100644
--- a/include/linux/key-type.h
+++ b/include/linux/key-type.h@@ -147,6 +147,15 @@ struct key_type { */ request_key_actor_t request_key; + /* Look up a keyring access restriction (optional) + * + * - The caller must hold a read lock on the key type's semaphore + * - 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 */
--
2.12.0
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