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Commit 03e68060 authored by James Morris's avatar James Morris Committed by Linus Torvalds
Browse files

[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: default avatarJames Morris <jmorris@namei.org>
Acked-by: default avatarStephen 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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9216dfad

fs/ioprio.c

+6 −0
Original line number Diff line number Diff line
@@ -24,15 +24,21 @@ 
#include <linux/blkdev.h>

#include <linux/capability.h>

#include <linux/syscalls.h>

#include <linux/security.h>



static int set_task_ioprio(struct task_struct *task, int ioprio)

{

	int err;

	struct io_context *ioc;



	if (task->uid != current->euid &&

	    task->uid != current->uid && !capable(CAP_SYS_NICE))

		return -EPERM;



	err = security_task_setioprio(task, ioprio);

	if (err)

		return err;



	task_lock(task);



	task->ioprio = ioprio;

include/linux/security.h

+16 −0
Original line number Diff line number Diff line
@@ -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)

{

security/dummy.c

+6 −0
Original line number Diff line number Diff line
@@ -516,6 +516,11 @@ static int dummy_task_setnice (struct task_struct *p, int nice) 
	return 0;

}



static int dummy_task_setioprio (struct task_struct *p, int ioprio)

{

	return 0;

}



static int dummy_task_setrlimit (unsigned int resource, struct rlimit *new_rlim)

{

	return 0;
@@ -972,6 +977,7 @@ void security_fixup_ops (struct security_operations *ops) 
	set_to_dummy_if_null(ops, task_getsid);

	set_to_dummy_if_null(ops, task_setgroups);

	set_to_dummy_if_null(ops, task_setnice);

	set_to_dummy_if_null(ops, task_setioprio);

	set_to_dummy_if_null(ops, task_setrlimit);

	set_to_dummy_if_null(ops, task_setscheduler);

	set_to_dummy_if_null(ops, task_getscheduler);

security/selinux/hooks.c

+6 −0
Original line number Diff line number Diff line
@@ -2645,6 +2645,11 @@ static int selinux_task_setnice(struct task_struct *p, int nice) 
	return task_has_perm(current,p, PROCESS__SETSCHED);

}



static int selinux_task_setioprio(struct task_struct *p, int ioprio)

{

	return task_has_perm(current, p, PROCESS__SETSCHED);

}



static int selinux_task_setrlimit(unsigned int resource, struct rlimit *new_rlim)

{

	struct rlimit *old_rlim = current->signal->rlim + resource;
@@ -4383,6 +4388,7 @@ static struct security_operations selinux_ops = { 
	.task_getsid =		        selinux_task_getsid,

	.task_setgroups =		selinux_task_setgroups,

	.task_setnice =			selinux_task_setnice,

	.task_setioprio =		selinux_task_setioprio,

	.task_setrlimit =		selinux_task_setrlimit,

	.task_setscheduler =		selinux_task_setscheduler,

	.task_getscheduler =		selinux_task_getscheduler,