From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752050AbZHLWEv (ORCPT ); Wed, 12 Aug 2009 18:04:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751924AbZHLWEv (ORCPT ); Wed, 12 Aug 2009 18:04:51 -0400 Received: from sparc.brc.ubc.ca ([137.82.2.12]:65005 "EHLO sparc.brc.ubc.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751895AbZHLWEu (ORCPT ); Wed, 12 Aug 2009 18:04:50 -0400 From: Vincent Li To: linux-kernel@vger.kernel.org Cc: Andrew Morton , David Rientjes , Vincent Li Subject: [PATCH] fs/proc/task_mmu.c: fix clear_refs_write() input sanity check Date: Wed, 12 Aug 2009 15:04:50 -0700 Message-Id: <1250114690-24829-1-git-send-email-macli@brc.ubc.ca> X-Mailer: git-send-email 1.6.0.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton pointed out similar string hacking and obfuscated check for zero-length input at the end of the function, David Rientjes suggested to use strict_strtol to replace simple_strtol, this patch cover above suggestions, add removing of leading and trailing whitespace from user input. It does not change function behavious. This patch is rebased on mmotm-2009-08-04-14-22. Signed-off-by: Vincent Li --- fs/proc/task_mmu.c | 18 ++++++++---------- 1 files changed, 8 insertions(+), 10 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 2079969..026b532 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -494,18 +494,17 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, char buffer[PROC_NUMBUF], *end; struct mm_struct *mm; struct vm_area_struct *vma; - int type; + long res; memset(buffer, 0, sizeof(buffer)); if (count > sizeof(buffer) - 1) count = sizeof(buffer) - 1; if (copy_from_user(buffer, buf, count)) return -EFAULT; - type = simple_strtol(buffer, &end, 0); - if (type < CLEAR_REFS_ALL || type > CLEAR_REFS_MAPPED) + if (strict_strtol(strstrip(buffer), 10, &res) + return -EINVAL; + if (res < CLEAR_REFS_ALL || res > CLEAR_REFS_MAPPED) return -EINVAL; - if (*end == '\n') - end++; task = get_proc_task(file->f_path.dentry->d_inode); if (!task) return -ESRCH; @@ -529,9 +528,9 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, * Writing 3 to /proc/pid/clear_refs only affects file * mapped pages. */ - if (type == CLEAR_REFS_ANON && vma->vm_file) + if (res == CLEAR_REFS_ANON && vma->vm_file) continue; - if (type == CLEAR_REFS_MAPPED && !vma->vm_file) + if (res == CLEAR_REFS_MAPPED && !vma->vm_file) continue; walk_page_range(vma->vm_start, vma->vm_end, &clear_refs_walk); @@ -541,9 +540,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, mmput(mm); } put_task_struct(task); - if (end - buffer == 0) - return -EIO; - return end - buffer; + + return count; } const struct file_operations proc_clear_refs_operations = { -- 1.6.0.4