From: Linus Torvalds <torvalds@g5.osdl.org>
Date: Wed, 9 Nov 2005 19:33:07 +0000 (-0800)
Subject: Fix ptrace self-attach rule
X-Git-Tag: v2.6.15-rc1~66
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=28d838cc4dfea980cb6eda0a7409cbf91889ca74;p=linux-2.6

Fix ptrace self-attach rule

Before we did CLONE_THREAD, the way to check whether we were attaching
to ourselves was to just check "current == task", but with CLONE_THREAD
we should check that the thread group ID matches instead.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 5b8dd98a23..b88d4186cd 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -155,7 +155,7 @@ int ptrace_attach(struct task_struct *task)
 	retval = -EPERM;
 	if (task->pid <= 1)
 		goto bad;
-	if (task == current)
+	if (task->tgid == current->tgid)
 		goto bad;
 	/* the same process cannot be attached many times */
 	if (task->ptrace & PT_PTRACED)