Re: [PATCH] ipvs: Add boundary check on ioctl arguments

[Arjan van de Ven <arjan@infradead.org>]

On Wed, 30 Sep 2009 13:11:09 +0200
Arjan van de Ven <arjan@infradead.org> wrote:

ping on the patch below.... the warning is now triggered in mainline


> 
> >From 761a182f96b3707e1fee44e1079ba227e48745d1 Mon Sep 17 00:00:00
> >2001
> From: Arjan van de Ven <arjan@linux.intel.com>
> Date: Wed, 30 Sep 2009 13:05:51 +0200
> Subject: [PATCH] ipvs: Add boundary check on ioctl arguments
> 
> The ipvs code has a nifty system for doing the size of ioctl command
> copies; it defines an array with values into which it indexes the cmd
> to find the right length.
> 
> Unfortunately, the ipvs code forgot to check if the cmd was in the
> range that the array provides, allowing for an index outside of the
> array, which then gives a "garbage" result into the length, which
> then gets used for copying into a stack buffer.
> 
> Fix this by adding sanity checks on these as well as the copy size.
> 
> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
> ---
>  net/netfilter/ipvs/ip_vs_ctl.c |   14 +++++++++++++-
>  1 files changed, 13 insertions(+), 1 deletions(-)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c
> b/net/netfilter/ipvs/ip_vs_ctl.c index ac624e5..3c52796 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -2077,6 +2077,10 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd,
> void __user *user, unsigned int len) if (!capable(CAP_NET_ADMIN))
>  		return -EPERM;
>  
> +	if (cmd < IP_VS_BASE_CTL || cmd > IP_VS_SO_SET_MAX + 1)
> +		return -EINVAL;
> +	if (len < 0 || len >  MAX_ARG_LEN)
> +		return -EINVAL;
>  	if (len != set_arglen[SET_CMDID(cmd)]) {
>  		pr_err("set_ctl: len %u != %u\n",
>  		       len, set_arglen[SET_CMDID(cmd)]);
> @@ -2353,17 +2357,25 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd,
> void __user *user, int *len) {
>  	unsigned char arg[128];
>  	int ret = 0;
> +	unsigned int copylen;
>  
>  	if (!capable(CAP_NET_ADMIN))
>  		return -EPERM;
>  
> +	if (cmd < IP_VS_BASE_CTL || cmd > IP_VS_SO_GET_MAX + 1)
> +		return -EINVAL;
> +
>  	if (*len < get_arglen[GET_CMDID(cmd)]) {
>  		pr_err("get_ctl: len %u < %u\n",
>  		       *len, get_arglen[GET_CMDID(cmd)]);
>  		return -EINVAL;
>  	}
>  
> -	if (copy_from_user(arg, user, get_arglen[GET_CMDID(cmd)]) !=
> 0)
> +	copylen = get_arglen[GET_CMDID(cmd)];
> +	if (copylen > 128)
> +		return -EINVAL;
> +
> +	if (copy_from_user(arg, user, copylen) != 0)
>  		return -EFAULT;
>  
>  	if (mutex_lock_interruptible(&__ip_vs_mutex))


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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