From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755442Ab0AMOAp (ORCPT ); Wed, 13 Jan 2010 09:00:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755418Ab0AMOAl (ORCPT ); Wed, 13 Jan 2010 09:00:41 -0500 Received: from mga02.intel.com ([134.134.136.20]:28557 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755385Ab0AMOAk (ORCPT ); Wed, 13 Jan 2010 09:00:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.49,268,1262592000"; d="scan'208";a="586774959" Message-Id: <20100113135957.402344716@intel.com> User-Agent: quilt/0.48-1 Date: Wed, 13 Jan 2010 21:53:07 +0800 From: Wu Fengguang To: Andrew Morton Cc: Wu Fengguang , LKML , Kelly Bowa , Greg Kroah-Hartman , Hugh Dickins , , KAMEZAWA Hiroyuki CC: Andi Kleen CC: Nick Piggin cc: Linux Memory Management List Subject: [PATCH 2/8] devmem: check vmalloc address on kmem read/write References: <20100113135305.013124116@intel.com> Content-Disposition: inline; filename=vmalloc-addr-fix.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KAMEZAWA Hiroyuki Otherwise vmalloc_to_page() will BUG(). This also makes the kmem read/write implementation aligned with mem(4): "References to nonexistent locations cause errors to be returned." Here we return -ENXIO (inspired by Hugh) if no bytes have been transfered to/from user space, otherwise return partial read/write results. CC: Kelly Bowa CC: Greg Kroah-Hartman CC: Hugh Dickins CC: Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Wu Fengguang --- drivers/char/mem.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) --- linux-mm.orig/drivers/char/mem.c 2010-01-11 10:22:35.000000000 +0800 +++ linux-mm/drivers/char/mem.c 2010-01-11 10:32:32.000000000 +0800 @@ -395,6 +395,7 @@ static ssize_t read_kmem(struct file *fi unsigned long p = *ppos; ssize_t low_count, read, sz; char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ + int err = 0; read = 0; if (p < (unsigned long) high_memory) { @@ -441,12 +442,16 @@ static ssize_t read_kmem(struct file *fi return -ENOMEM; while (count > 0) { sz = size_inside_page(p, count); + if (!is_vmalloc_or_module_addr((void *)p)) { + err = -ENXIO; + break; + } sz = vread(kbuf, (char *)p, sz); if (!sz) break; if (copy_to_user(buf, kbuf, sz)) { - free_page((unsigned long)kbuf); - return -EFAULT; + err = -EFAULT; + break; } count -= sz; buf += sz; @@ -455,8 +460,8 @@ static ssize_t read_kmem(struct file *fi } free_page((unsigned long)kbuf); } - *ppos = p; - return read; + *ppos = p; + return read ? read : err; } @@ -520,6 +525,7 @@ static ssize_t write_kmem(struct file * ssize_t wrote = 0; ssize_t virtr = 0; char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ + int err = 0; if (p < (unsigned long) high_memory) { unsigned long to_write = min_t(unsigned long, count, @@ -540,12 +546,14 @@ static ssize_t write_kmem(struct file * unsigned long sz = size_inside_page(p, count); unsigned long n; + if (!is_vmalloc_or_module_addr((void *)p)) { + err = -ENXIO; + break; + } n = copy_from_user(kbuf, buf, sz); if (n) { - if (wrote + virtr) - break; - free_page((unsigned long)kbuf); - return -EFAULT; + err = -EFAULT; + break; } sz = vwrite(kbuf, (char *)p, sz); count -= sz; @@ -556,8 +564,8 @@ static ssize_t write_kmem(struct file * free_page((unsigned long)kbuf); } - *ppos = p; - return virtr + wrote; + *ppos = p; + return virtr + wrote ? : err; } #endif