Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752137Ab2HTEAl (ORCPT ); Mon, 20 Aug 2012 00:00:41 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:51799 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406Ab2HTEAh (ORCPT ); Mon, 20 Aug 2012 00:00:37 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Fengguang Wu , Oleg Nesterov , Kees Cook , John Johansen , James Morris Subject: [ 21/46] Yama: access task_struct->comm directly Date: Sun, 19 Aug 2012 20:58:57 -0700 Message-Id: <20120820035835.212441157@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.2.565.gbd578b5 In-Reply-To: <20120820035832.274275502@linuxfoundation.org> References: <20120820035832.274275502@linuxfoundation.org> User-Agent: quilt/0.60-20.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1954 Lines: 64 From: Greg KH 3.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit 7612bfeecc197bbb6629842b5c6ff1967f0a9b70 upstream. The core ptrace access checking routine holds a task lock, and when reporting a failure, Yama takes a separate task lock. To avoid a potential deadlock with two ptracers taking the opposite locks, do not use get_task_comm() and just use ->comm directly since accuracy is not important for the report. Reported-by: Fengguang Wu Suggested-by: Oleg Nesterov Signed-off-by: Kees Cook Acked-by: John Johansen Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman --- security/yama/yama_lsm.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) --- a/security/yama/yama_lsm.c +++ b/security/yama/yama_lsm.c @@ -279,12 +279,9 @@ static int yama_ptrace_access_check(stru } if (rc) { - char name[sizeof(current->comm)]; printk_ratelimited(KERN_NOTICE "ptrace of pid %d was attempted by: %s (pid %d)\n", - child->pid, - get_task_comm(name, current), - current->pid); + child->pid, current->comm, current->pid); } return rc; @@ -319,12 +316,9 @@ static int yama_ptrace_traceme(struct ta } if (rc) { - char name[sizeof(current->comm)]; printk_ratelimited(KERN_NOTICE "ptraceme of pid %d was attempted by: %s (pid %d)\n", - current->pid, - get_task_comm(name, parent), - parent->pid); + current->pid, parent->comm, parent->pid); } return rc; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/