Subject: Re: ktrace and P_SUGID
To: Simon J. Gerraty <sjg@crufty.net>
From: None <itojun@iijlab.net>
List: tech-security
Date: 06/29/2002 15:20:57
>I trust that this restriction does not apply if the ktrace was initiated
>by root?  I've not looked at the netbsd ktrace paths, but I had to
>fix the freebsd kernel to allow ktrace across exec of a setuid binary
>when the trace was initiated by root - otherwise its nearly impossible
>to debug certain classes of bug.

	the following line takes care of "invoked by root" case.

itojun


	if ((caller->pc_ucred->cr_uid == target->p_ruid &&
	     target->p_ruid == target->p_svuid &&
	     caller->p_rgid == target->p_rgid &&        /* XXX */
	     target->p_rgid == target->p_svgid &&
	     (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
	     (targetp->p_flag & P_SUGID) == 0) ||
	     caller->pc_ucred->cr_uid == 0)		<----
		return (1);