selinux: selinux_bprm_committed_creds() should wake up ->real_parent, not ->parent. (ecd6de3c) · Commits · 戴 / test

We shouldn't worry about the tracer if current is ptraced, exec() must not succeed if the tracer has no rights to trace this task after cred changing. But we should notify ->real_parent which is, well, real parent. Also, we don't need _irq to take tasklist, and we don't need parent's ->siglock to wake_up_interruptible(real_parent->signal->wait_chldexit). Since we hold tasklist, real_parent->signal must be stable. Otherwise spin_lock(siglock) is not safe too and can't help anyway. Signed-off-by:

Oleg Nesterov <oleg@redhat.com> Signed-off-by:

James Morris <jmorris@namei.org>

security/selinux/hooks.c

+3 −8

Original line number	Diff line number	Diff line
		@@ -2371,10 +2371,8 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
		{
		const struct task_security_struct *tsec = current_security();
		struct itimerval itimer;
		struct sighand_struct *psig;
		u32 osid, sid;
		int rc, i;
		unsigned long flags;

		osid = tsec->osid;
		sid = tsec->sid;
		@@ -2405,12 +2403,9 @@ static void selinux_bprm_committed_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);
		read_lock(&tasklist_lock);
		wake_up_interruptible(&current->real_parent->signal->wait_chldexit);
		read_unlock(&tasklist_lock);
		}

		/* superblock security operations */

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