Date: Wed, 6 Feb 2002 07:20:03 -0800 (PST) From: "Tim J. Robbins" <tim@robbins.dropbear.id.au> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/29741: ptrace(pid);ptrace(ppid) makes pid and ppid unkillable Message-ID: <200202061520.g16FK3t28746@freefall.freebsd.org>
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The following reply was made to PR kern/29741; it has been noted by GNATS.
From: "Tim J. Robbins" <tim@robbins.dropbear.id.au>
To: Dave Zarzycki <zarzycki@FreeBSD.org>
Cc: freebsd-gnats-submit@FreeBSD.org
Subject: Re: kern/29741: ptrace(pid);ptrace(ppid) makes pid and ppid unkillable
Date: Thu, 7 Feb 2002 02:10:26 +1100
This patch (against RELENG_4) does solve the gdb -> gdb -> gdb -> grandparent
problem.
I don't think the "if (curp->p_flag & P_TRACED)" bit is even necessary at all;
ptrace()'ing an ancestor seems like a bad idea to me, regardless of whether
you're being traced or not.
--- sys_process.c.old Thu Feb 7 00:05:09 2002
+++ sys_process.c Thu Feb 7 01:27:36 2002
@@ -203,7 +203,7 @@
struct proc *curp;
struct ptrace_args *uap;
{
- struct proc *p;
+ struct proc *p, *pp;
struct iovec iov;
struct uio uio;
int error = 0;
@@ -240,6 +240,12 @@
/* Already traced */
if (p->p_flag & P_TRACED)
return EBUSY;
+
+ /* Can't trace an ancestor if you're being traced */
+ if (curp->p_flag & P_TRACED)
+ for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr)
+ if (pp == p)
+ return EINVAL;
/* not owned by you, has done setuid (unless you're root) */
if ((p->p_cred->p_ruid != curp->p_cred->p_ruid) ||
Tim
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