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author | David Howells <dhowells@redhat.com> | 2008-11-14 10:39:26 +1100 |
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committer | James Morris <jmorris@namei.org> | 2008-11-14 10:39:26 +1100 |
commit | 3b11a1decef07c19443d24ae926982bc8ec9f4c0 (patch) | |
tree | b6555f0e5b07f4b2badd332a0a900b974920c49d /security/Kconfig | |
parent | 98870ab0a5a3f1822aee681d2997017e1c87d026 (diff) | |
download | op-kernel-dev-3b11a1decef07c19443d24ae926982bc8ec9f4c0.zip op-kernel-dev-3b11a1decef07c19443d24ae926982bc8ec9f4c0.tar.gz |
CRED: Differentiate objective and effective subjective credentials on a task
Differentiate the objective and real subjective credentials from the effective
subjective credentials on a task by introducing a second credentials pointer
into the task_struct.
task_struct::real_cred then refers to the objective and apparent real
subjective credentials of a task, as perceived by the other tasks in the
system.
task_struct::cred then refers to the effective subjective credentials of a
task, as used by that task when it's actually running. These are not visible
to the other tasks in the system.
__task_cred(task) then refers to the objective/real credentials of the task in
question.
current_cred() refers to the effective subjective credentials of the current
task.
prepare_creds() uses the objective creds as a base and commit_creds() changes
both pointers in the task_struct (indeed commit_creds() requires them to be the
same).
override_creds() and revert_creds() change the subjective creds pointer only,
and the former returns the old subjective creds. These are used by NFSD,
faccessat() and do_coredump(), and will by used by CacheFiles.
In SELinux, current_has_perm() is provided as an alternative to
task_has_perm(). This uses the effective subjective context of current,
whereas task_has_perm() uses the objective/real context of the subject.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/Kconfig')
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