[PATCH] lsm: add task_setioprio hook

Implement an LSM hook for setting a task's IO priority, similar to the hook
for setting a tasks's nice value.

A previous version of this LSM hook was included in an older version of
multiadm by Jan Engelhardt, although I don't recall it being submitted
upstream.

Also included is the corresponding SELinux hook, which re-uses the setsched
permission in the proccess class.

Signed-off-by: James Morris <jmorris@namei.org>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/security.h b/include/linux/security.h
index 383c320fc834..65b32a0c6207 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -577,6 +577,11 @@ struct swap_info_struct;
  *      @p contains the task_struct of process.
  *      @nice contains the new nice value.
  *      Return 0 if permission is granted.
+ * @task_setioprio
+ *      Check permission before setting the ioprio value of @p to @ioprio.
+ *      @p contains the task_struct of process.
+ *      @ioprio contains the new ioprio value
+ *      Return 0 if permission is granted.
  * @task_setrlimit:
  *      Check permission before setting the resource limits of the current
  *      process for @resource to @new_rlim.  The old resource limit values can
@@ -1210,6 +1215,7 @@ struct security_operations {
         int (*task_getsid) (struct task_struct * p);
         int (*task_setgroups) (struct group_info *group_info);
         int (*task_setnice) (struct task_struct * p, int nice);
+        int (*task_setioprio) (struct task_struct * p, int ioprio);
         int (*task_setrlimit) (unsigned int resource, struct rlimit * new_rlim);
         int (*task_setscheduler) (struct task_struct * p, int policy,
                                   struct sched_param * lp);
@@ -1836,6 +1842,11 @@ static inline int security_task_setnice (struct task_struct *p, int nice)
         return security_ops->task_setnice (p, nice);
 }
 
+static inline int security_task_setioprio (struct task_struct *p, int ioprio)
+{
+        return security_ops->task_setioprio (p, ioprio);
+}
+
 static inline int security_task_setrlimit (unsigned int resource,
                                            struct rlimit *new_rlim)
 {
@@ -2478,6 +2489,11 @@ static inline int security_task_setnice (struct task_struct *p, int nice)
         return 0;
 }
 
+static inline int security_task_setioprio (struct task_struct *p, int ioprio)
+{
+        return 0;
+}
+
 static inline int security_task_setrlimit (unsigned int resource,
                                            struct rlimit *new_rlim)
 {