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Message-ID: <20090817024858.GG5039@cr0.nay.redhat.com>
Date: Mon, 17 Aug 2009 10:48:58 +0800
From: Amerigo Wang <xiyou.wangcong@...il.com>
To: Vincent Li <macli@....ubc.ca>
Cc: linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] fs/proc/base.c: fix proc_fault_inject_write() input
sanity check
On Fri, Aug 14, 2009 at 01:18:40PM -0700, Vincent Li wrote:
>Remove obfuscated zero-length input check and return -EINVAL instead of -EIO error
>to make the error message clear to user. Add whitespace stripping. No functionality changes.
If so, why not introduce a new wrapper which is simply strstrip+simple_strtol?
Now, at least it has two users.
>
>The old code:
>
>echo 1 > /proc/pid/make-it-fail (ok)
>echo 1foo > /proc/pid/make-it-fail (-bash: echo: write error: Input/output error)
>
>The new code:
>
>echo 1 > /proc/pid/make-it-fail (ok)
>echo 1foo > /proc/pid/make-it-fail (-bash: echo: write error: Invalid argument)
>
>This patch is conservative in changes to not breaking existing scripts/applications.
>based on v2.6.31-rc6, compiled and tested ok.
>
>Signed-off-by: Vincent Li <macli@....ubc.ca>
>---
> fs/proc/base.c | 11 +++++------
> 1 files changed, 5 insertions(+), 6 deletions(-)
>
>diff --git a/fs/proc/base.c b/fs/proc/base.c
>index 175db25..ba345d9 100644
>--- a/fs/proc/base.c
>+++ b/fs/proc/base.c
>@@ -1182,17 +1182,16 @@ static ssize_t proc_fault_inject_write(struct file * file,
> count = sizeof(buffer) - 1;
> if (copy_from_user(buffer, buf, count))
> return -EFAULT;
>- make_it_fail = simple_strtol(buffer, &end, 0);
>- if (*end == '\n')
>- end++;
>+ make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
>+ if (*end)
>+ return -EINVAL;
> task = get_proc_task(file->f_dentry->d_inode);
> if (!task)
> return -ESRCH;
> task->make_it_fail = make_it_fail;
> put_task_struct(task);
>- if (end - buffer == 0)
>- return -EIO;
>- return end - buffer;
>+
>+ return count;
> }
>
> static const struct file_operations proc_fault_inject_operations = {
>--
>1.6.0.4
>
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