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From: James Morris <jmorris@namei.org>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, Stephen Smalley <sds@tycho.nsa.gov>,
	Chris Wright <chrisw@sous-sol.org>,
	David Quigley <dpquigl@tycho.nsa.gov>,
	Eric Paris <eparis@redhat.com>
Subject: [PATCH] SELinux: Add security hook definition for getioprio and insert hooks
Date: Thu, 29 Jun 2006 17:04:58 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.64.0606291702380.26876@d.namei> (raw)

From: David Quigley <dpquigl@tycho.nsa.gov>
 
This patch adds a new security hook definition for the sys_ioprio_get 
operation. At present, the SELinux hook function implementation for this 
hook is identical to the getscheduler implementation but a separate hook 
is introduced to allow this check to be specialized in the future if 
necessary. This patch also creates a helper function get_task_ioprio which 
handles the access check in addition to retrieving the ioprio value for 
the task.

Signed-Off-By: David Quigley <dpquigl@tycho.nsa.gov>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>


Please apply.

---

 fs/ioprio.c              |   29 ++++++++++++++++++++++++-----
 include/linux/security.h |   15 +++++++++++++++
 security/dummy.c         |    6 ++++++
 security/selinux/hooks.c |    6 ++++++
 4 files changed, 51 insertions(+), 5 deletions(-)

diff -uprN -X /home/dpquigl/dontdiff linux-2.6.17-mm3/fs/ioprio.c linux-2.6.17-mm3-ioprio/fs/ioprio.c
--- linux-2.6.17-mm3/fs/ioprio.c	2006-06-28 13:58:56.000000000 -0400
+++ linux-2.6.17-mm3-ioprio/fs/ioprio.c	2006-06-29 15:58:29.000000000 -0400
@@ -125,11 +125,24 @@ asmlinkage long sys_ioprio_set(int which
 	return ret;
 }
 
+static int get_task_ioprio(struct task_struct *p)
+{
+	int ret;
+
+	ret = security_task_getioprio(p);
+	if (ret)
+		goto out;
+	ret = p->ioprio;
+out:
+	return ret;
+}
+
 asmlinkage long sys_ioprio_get(int which, int who)
 {
 	struct task_struct *g, *p;
 	struct user_struct *user;
 	int ret = -ESRCH;
+	int tmpio;
 
 	read_lock_irq(&tasklist_lock);
 	switch (which) {
@@ -139,16 +152,19 @@ asmlinkage long sys_ioprio_get(int which
 			else
 				p = find_task_by_pid(who);
 			if (p)
-				ret = p->ioprio;
+				ret = get_task_ioprio(p);
 			break;
 		case IOPRIO_WHO_PGRP:
 			if (!who)
 				who = process_group(current);
 			do_each_task_pid(who, PIDTYPE_PGID, p) {
+				tmpio = get_task_ioprio(p);
+				if (tmpio < 0)
+					continue;
 				if (ret == -ESRCH)
-					ret = p->ioprio;
+					ret = tmpio;
 				else
-					ret = ioprio_best(ret, p->ioprio);
+					ret = ioprio_best(ret, tmpio);
 			} while_each_task_pid(who, PIDTYPE_PGID, p);
 			break;
 		case IOPRIO_WHO_USER:
@@ -163,10 +179,13 @@ asmlinkage long sys_ioprio_get(int which
 			do_each_thread(g, p) {
 				if (p->uid != user->uid)
 					continue;
+				tmpio = get_task_ioprio(p);
+				if (tmpio < 0)
+					continue;
 				if (ret == -ESRCH)
-					ret = p->ioprio;
+					ret = tmpio;
 				else
-					ret = ioprio_best(ret, p->ioprio);
+					ret = ioprio_best(ret, tmpio);
 			} while_each_thread(g, p);
 
 			if (who)
diff -uprN -X /home/dpquigl/dontdiff linux-2.6.17-mm3/include/linux/security.h linux-2.6.17-mm3-ioprio/include/linux/security.h
--- linux-2.6.17-mm3/include/linux/security.h	2006-06-28 13:58:59.000000000 -0400
+++ linux-2.6.17-mm3-ioprio/include/linux/security.h	2006-06-28 11:21:37.000000000 -0400
@@ -582,6 +582,10 @@ struct swap_info_struct;
  *	@p contains the task_struct of process.
  *	@ioprio contains the new ioprio value
  *	Return 0 if permission is granted.
+ * @task_getioprio
+ *	Check permission before getting the ioprio value of @p.
+ *	@p contains the task_struct of process.
+ *	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
@@ -1221,6 +1225,7 @@ struct security_operations {
 	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_getioprio) (struct task_struct * p);
 	int (*task_setrlimit) (unsigned int resource, struct rlimit * new_rlim);
 	int (*task_setscheduler) (struct task_struct * p, int policy,
 				  struct sched_param * lp);
@@ -1853,6 +1858,11 @@ static inline int security_task_setiopri
 	return security_ops->task_setioprio (p, ioprio);
 }
 
+static inline int security_task_getioprio (struct task_struct *p)
+{
+	return security_ops->task_getioprio (p);
+}
+
 static inline int security_task_setrlimit (unsigned int resource,
 					   struct rlimit *new_rlim)
 {
@@ -2505,6 +2515,11 @@ static inline int security_task_setiopri
 	return 0;
 }
 
+static inline int security_task_getioprio (struct task_struct *p)
+{
+	return 0;
+}
+
 static inline int security_task_setrlimit (unsigned int resource,
 					   struct rlimit *new_rlim)
 {
diff -uprN -X /home/dpquigl/dontdiff linux-2.6.17-mm3/security/dummy.c linux-2.6.17-mm3-ioprio/security/dummy.c
--- linux-2.6.17-mm3/security/dummy.c	2006-06-28 13:58:59.000000000 -0400
+++ linux-2.6.17-mm3-ioprio/security/dummy.c	2006-06-28 11:23:00.000000000 -0400
@@ -521,6 +521,11 @@ static int dummy_task_setioprio (struct 
 	return 0;
 }
 
+static int dummy_task_getioprio (struct task_struct *p)
+{
+	return 0;
+}
+
 static int dummy_task_setrlimit (unsigned int resource, struct rlimit *new_rlim)
 {
 	return 0;
@@ -984,6 +989,7 @@ void security_fixup_ops (struct security
 	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_getioprio);
 	set_to_dummy_if_null(ops, task_setrlimit);
 	set_to_dummy_if_null(ops, task_setscheduler);
 	set_to_dummy_if_null(ops, task_getscheduler);
diff -uprN -X /home/dpquigl/dontdiff linux-2.6.17-mm3/security/selinux/hooks.c linux-2.6.17-mm3-ioprio/security/selinux/hooks.c
--- linux-2.6.17-mm3/security/selinux/hooks.c	2006-06-28 13:58:59.000000000 -0400
+++ linux-2.6.17-mm3-ioprio/security/selinux/hooks.c	2006-06-28 11:49:13.000000000 -0400
@@ -2665,6 +2665,11 @@ static int selinux_task_setioprio(struct
 	return task_has_perm(current, p, PROCESS__SETSCHED);
 }
 
+static int selinux_task_getioprio(struct task_struct *p)
+{
+	return task_has_perm(current, p, PROCESS__GETSCHED);
+}
+
 static int selinux_task_setrlimit(unsigned int resource, struct rlimit *new_rlim)
 {
 	struct rlimit *old_rlim = current->signal->rlim + resource;
@@ -4432,6 +4437,7 @@ static struct security_operations selinu
 	.task_setgroups =		selinux_task_setgroups,
 	.task_setnice =			selinux_task_setnice,
 	.task_setioprio =		selinux_task_setioprio,
+	.task_getioprio =		selinux_task_getioprio,
 	.task_setrlimit =		selinux_task_setrlimit,
 	.task_setscheduler =		selinux_task_setscheduler,
 	.task_getscheduler =		selinux_task_getscheduler,

             reply	other threads:[~2006-06-29 21:05 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-29 21:04 James Morris [this message]
2006-06-30 19:37 ` Serge E. Hallyn
2006-06-30 19:58   ` Stephen Smalley
2006-07-01  0:26     ` Serge E. Hallyn

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