Re: [PATCH] SN2: security hole in sn2_ptc_proc_write

Andi Kleen
2008-06-22T17:41:35Z

Cliff Wickman <cpw@sgi.com> writes:
>
> Signed-off-by: Cliff Wickman <cpw@sgi.com>
> ---
> arch/ia64/sn/kernel/sn2/sn2_smp.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> Index: linux-2.6/arch/ia64/sn/kernel/sn2/sn2_smp.c
> =================================> --- linux-2.6.orig/arch/ia64/sn/kernel/sn2/sn2_smp.c
> +++ linux-2.6/arch/ia64/sn/kernel/sn2/sn2_smp.c
> @@ -512,6 +512,8 @@ static ssize_t sn2_ptc_proc_write(struct
> int cpu;
> char optstr[64];
>
> + if (count > 64)
> + return -EINVAL;
> if (copy_from_user(optstr, user, count))
> return -EFAULT;
> optstr[count - 1] = '\0';

When someone passes 0 you get an buffer underflow?

You need if (count < 0 || count > 64) me thinks.

-Andi