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Commit 41d9f9c5 authored by Eric Paris's avatar Eric Paris Committed by James Morris
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SELinux: hold tasklist_lock and siglock while waking wait_chldexit 



SELinux has long been calling wake_up_interruptible() on
current->parent->signal->wait_chldexit without holding any locks.  It
appears that this operation should hold the tasklist_lock to dereference
current->parent and we should hold the siglock when waking up the
signal->wait_chldexit.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 8b6a5a37

security/selinux/hooks.c

+7 −0
Original line number Diff line number Diff line
@@ -2268,7 +2268,9 @@ static void selinux_bprm_post_apply_creds(struct linux_binprm *bprm) 
	struct rlimit *rlim, *initrlim;

	struct itimerval itimer;

	struct bprm_security_struct *bsec;

	struct sighand_struct *psig;

	int rc, i;

	unsigned long flags;



	tsec = current->security;

	bsec = bprm->security;
@@ -2335,7 +2337,12 @@ static void selinux_bprm_post_apply_creds(struct linux_binprm *bprm) 


	/* Wake up the parent if it is waiting so that it can

	   recheck wait permission to the new task SID. */

	read_lock_irq(&tasklist_lock);

	psig = current->parent->sighand;

	spin_lock_irqsave(&psig->siglock, flags);

	wake_up_interruptible(&current->parent->signal->wait_chldexit);

	spin_unlock_irqrestore(&psig->siglock, flags);

	read_unlock_irq(&tasklist_lock);

}



/* superblock security operations */