From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756875AbYBYPvT (ORCPT ); Mon, 25 Feb 2008 10:51:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755036AbYBYPux (ORCPT ); Mon, 25 Feb 2008 10:50:53 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:50396 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754787AbYBYPuw (ORCPT ); Mon, 25 Feb 2008 10:50:52 -0500 Date: Mon, 25 Feb 2008 16:50:38 +0100 From: Ingo Molnar To: Linus Torvalds Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: [patch] printk: fix possible printk overrun Message-ID: <20080225155038.GA25423@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Subject: printk: fix possible printk overrun From: Tejun Heo Date: Thu, 14 Feb 2008 10:32:07 +0900 printk recursion detection prepends message to printk_buf and offsets printk_buf when actual message is printed but it forgets to trim buffer length accordingly. This can result in overrun in extreme cases. Fix it. [ mingo@elte.hu: bug was introduced by me via: commit 32a76006683f7b28ae3cc491da37716e002f198e Author: Ingo Molnar Date: Fri Jan 25 21:07:58 2008 +0100 printk: make printk more robust by not allowing recursion ] Signed-off-by: Tejun Heo Signed-off-by: Ingo Molnar --- kernel/printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux/kernel/printk.c =================================================================== --- linux.orig/kernel/printk.c +++ linux/kernel/printk.c @@ -666,7 +666,7 @@ asmlinkage int vprintk(const char *fmt, } /* Emit the output into the temporary buffer */ printed_len += vscnprintf(printk_buf + printed_len, - sizeof(printk_buf), fmt, args); + sizeof(printk_buf) - printed_len, fmt, args); /* * Copy the output into log_buf. If the caller didn't provide