Messages in this thread Patch in this message | | | Date | Wed, 29 Apr 2009 16:02:24 +0200 | From | Oleg Nesterov <> | Subject | ptrace: selinux_bprm_committed_creds: simplify __wake_up_parent() code and s/parent/real_parent/ |
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(on top of David's "[PATCH] SELinux: Don't flush inherited SIGKILL during execve()", but can be applied independently).
selinux_bprm_committed_creds() should wake up ->real_parent, not ->parent.
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>
--- PTRACE/security/selinux/hooks.c~SELINUX_PARENT 2009-04-29 15:45:28.000000000 +0200 +++ PTRACE/security/selinux/hooks.c 2009-04-29 15:48:41.000000000 +0200 @@ -2375,10 +2375,8 @@ static void selinux_bprm_committed_creds { 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; @@ -2409,12 +2407,9 @@ static void selinux_bprm_committed_creds /* 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(¤t->parent->signal->wait_chldexit); - spin_unlock_irqrestore(&psig->siglock, flags); - read_unlock_irq(&tasklist_lock); + read_lock(&tasklist_lock); + wake_up_interruptible(¤t->real_parent->signal->wait_chldexit); + read_unlock(&tasklist_lock); } /* superblock security operations */
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