From: "J. Bruce Fields" <bfields@fieldses•org>
To: Sasha Levin <levinsasha928@gmail•com>
Cc: Trond.Myklebust@netapp•com, davem@davemloft•net,
davej@redhat•com, linux-nfs@vger•kernel.org,
netdev@vger•kernel.org, linux-kernel@vger•kernel.org
Subject: Re: [PATCH] SUNRPC: Prevent kernel stack corruption on long values of flush
Date: Wed, 18 Jul 2012 13:39:13 -0400 [thread overview]
Message-ID: <20120718173913.GA1298@fieldses.org> (raw)
In-Reply-To: <1342476086-21638-1-git-send-email-levinsasha928@gmail.com>
On Tue, Jul 17, 2012 at 12:01:26AM +0200, Sasha Levin wrote:
> The buffer size in read_flush() is too small for the longest possible values
> for it. This can lead to a kernel stack corruption:
Thanks!
>
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index 2afd2a8..f86d95e 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -1409,11 +1409,11 @@ static ssize_t read_flush(struct file *file, char __user *buf,
> size_t count, loff_t *ppos,
> struct cache_detail *cd)
> {
> - char tbuf[20];
> + char tbuf[22];
I wonder how common this sort of calculation is in the kernel? It might
provide some peace of mind to be able to write this something like
char tbuf[MAXLEN_BASE10_UL + 2] /* + 2 for final "\n\0" */
--b.
> unsigned long p = *ppos;
> size_t len;
>
> - sprintf(tbuf, "%lu\n", convert_to_wallclock(cd->flush_time));
> + snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
> len = strlen(tbuf);
> if (p >= len)
> return 0;
> --
> 1.7.8.6
>
next prev parent reply other threads:[~2012-07-18 17:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-16 22:01 [PATCH] SUNRPC: Prevent kernel stack corruption on long values of flush Sasha Levin
2012-07-18 17:39 ` J. Bruce Fields [this message]
2012-07-18 20:00 ` Jim Rees
[not found] ` <20120718200049.GA17964-63aXycvo3TyHXe+LvDLADg@public.gmane.org>
2012-07-18 20:33 ` Dave Jones
[not found] ` <20120718203304.GA18540-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-07-18 20:55 ` Jim Rees
[not found] ` <20120718205510.GA18374-63aXycvo3TyHXe+LvDLADg@public.gmane.org>
2012-10-17 18:29 ` Boaz Harrosh
[not found] ` <507EF918.5030004-C4P08NqkoRlBDgjK7y7TUQ@public.gmane.org>
2012-10-18 8:34 ` David Laight
2012-07-18 21:08 ` J. Bruce Fields
[not found] ` <50072BA7.6070205@gmail.com>
[not found] ` <50072BA7.6070205-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-07-18 21:43 ` Sasha Levin
[not found] ` <50072DEE.2000205-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-07-18 23:04 ` Jim Rees
[not found] ` <20120718173913.GA1298-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2012-10-17 17:59 ` Sasha Levin
[not found] ` <CA+1xoqcgWTP8pAY3Ok2R0JM-ZXSkGroEvAFcqP0KaK=dABiTXA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-17 19:02 ` J. Bruce Fields
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