From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755493Ab1IGErt (ORCPT ); Wed, 7 Sep 2011 00:47:49 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:38461 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755175Ab1IGErm (ORCPT ); Wed, 7 Sep 2011 00:47:42 -0400 From: Denys Vlasenko To: Oleg Nesterov Subject: [PATCH] Make PTRACE_SEIZE set ptrace options specified in data parameter Date: Wed, 7 Sep 2011 06:47:40 +0200 User-Agent: KMail/1.8.2 Cc: Denys Vlasenko , Tejun Heo , linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201109070647.40850.vda.linux@googlemail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make PTRACE_SEIZE set ptrace options specified in data parameter This can be used to close a few corner cases in strace where we get unwanted behavior after attach, but before we have a chance to set options (the notorious post-execve SIGTRAP comes to mind), and removes the need to track "did we set opts for this task?" state in strace internals. Signed-off-by: Denys Vlasenko diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 665ee93..ea83195 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -219,19 +219,23 @@ static int ptrace_attach(struct task_struct *task, long request, /* * SEIZE will enable new ptrace behaviors which will be implemented - * gradually. SEIZE_DEVEL is used to prevent applications + * gradually. SEIZE_DEVEL bit is used to prevent applications * expecting full SEIZE behaviors trapping on kernel commits which * are still in the process of implementing them. * * Only test programs for new ptrace behaviors being implemented * should set SEIZE_DEVEL. If unset, SEIZE will fail with -EIO. * - * Once SEIZE behaviors are completely implemented, this flag and - * the following test will be removed. + * Once SEIZE behaviors are completely implemented, this flag + * will be removed. */ retval = -EIO; - if (seize && !(flags & PTRACE_SEIZE_DEVEL)) - goto out; + if (seize) { + if ((flags & ~(long)PTRACE_O_MASK) != PTRACE_SEIZE_DEVEL) + goto out; + flags &= ~PTRACE_SEIZE_DEVEL; + } else + flags = 0; audit_ptrace(task); @@ -263,7 +267,7 @@ static int ptrace_attach(struct task_struct *task, long request, if (task->ptrace) goto unlock_tasklist; - task->ptrace = PT_PTRACED; + task->ptrace = PT_PTRACED | (flags << PT_OPT_FLAG_SHIFT); if (seize) task->ptrace |= PT_SEIZED; if (task_ns_capable(task, CAP_SYS_PTRACE))