[PATCH] SELinux: Add security hook definition for getioprio and insert hooks

Add 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>
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, 24 insertions, 5 deletions

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 7fa76ed53c10..93aa5715f224 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -125,11 +125,24 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
         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, int who)
                         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, int who)
                         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)