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Diffstat (limited to 'Documentation/keys.txt')
| -rw-r--r-- | Documentation/keys.txt | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/Documentation/keys.txt b/Documentation/keys.txt index aaa01b0e3ee..3bbe157b45e 100644 --- a/Documentation/keys.txt +++ b/Documentation/keys.txt @@ -19,6 +19,7 @@ This document has the following sections: - Key overview - Key service overview - Key access permissions + - SELinux support - New procfs files - Userspace system call interface - Kernel services @@ -232,6 +233,34 @@ For changing the ownership, group ID or permissions mask, being the owner of the key or having the sysadmin capability is sufficient. +=============== +SELINUX SUPPORT +=============== + +The security class "key" has been added to SELinux so that mandatory access +controls can be applied to keys created within various contexts. This support +is preliminary, and is likely to change quite significantly in the near future. +Currently, all of the basic permissions explained above are provided in SELinux +as well; SE Linux is simply invoked after all basic permission checks have been +performed. + +Each key is labeled with the same context as the task to which it belongs. +Typically, this is the same task that was running when the key was created. +The default keyrings are handled differently, but in a way that is very +intuitive: + + (*) The user and user session keyrings that are created when the user logs in + are currently labeled with the context of the login manager. + + (*) The keyrings associated with new threads are each labeled with the context + of their associated thread, and both session and process keyrings are + handled similarly. + +Note, however, that the default keyrings associated with the root user are +labeled with the default kernel context, since they are created early in the +boot process, before root has a chance to log in. + + ================ NEW PROCFS FILES ================ @@ -935,6 +964,16 @@ The structure has a number of fields, some of which are mandatory: It is not safe to sleep in this method; the caller may hold spinlocks. + (*) void (*revoke)(struct key *key); + + This method is optional. It is called to discard part of the payload + data upon a key being revoked. The caller will have the key semaphore + write-locked. + + It is safe to sleep in this method, though care should be taken to avoid + a deadlock against the key semaphore. + + (*) void (*destroy)(struct key *key); This method is optional. It is called to discard the payload data on a key |