ng_bridge(4) has an easily exploitable memory leak

[Julian Elischer]

On Wed, 7 Apr 2004, Ruslan Ermilov wrote:

> Hi,
> 
> On RELENG_4, ng_bridge(4) has an easily exploitable memory leak,
> and may quickly run system out of mbufs.  It's enough to just
> have only one link connected to the bridge, e.g., the "upper"
> hook of the ng_ether(4) with IP address assigned, and pinging
> the broadcast IP address on the interface.  The bug is more
> real when constructing a bridge, or, like we experienced it,
> by shutting down all except one bridge's link.  The following
> patch fixes it:
> 
> %%%
> Index: ng_bridge.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/netgraph/ng_bridge.c,v
> retrieving revision 1.1.2.6
> diff -u -p -r1.1.2.6 ng_bridge.c
> --- ng_bridge.c	9 Jan 2004 08:58:06 -0000	1.1.2.6
> +++ ng_bridge.c	7 Apr 2004 12:29:46 -0000
> @@ -656,6 +656,11 @@ ng_bridge_rcvdata(hook_p hook, struct mb
>  		link->stats.recvUnknown++;
>  	}
>  
> +	/* If there's only one link, stop right here. */
> +	if (priv->numLinks == 1) {
> +		NG_FREE_DATA(m, meta);
> +		return (0);
> +	}
>  	/* Distribute unknown, multicast, broadcast pkts to all other links */
>  	for (linkNum = i = 0; i < priv->numLinks - 1; linkNum++) {
>  		struct ng_bridge_link *const destLink = priv->links[linkNum];
> %%%
> 
> An alternate solution is to MFC most of ng_bridge.c,v 1.8.  Julian?

what does an MFC diff look like?
(bridge is one of archies's nodes)


> 
> 
> Cheers,
> -- 
> Ruslan Ermilov
> ru at FreeBSD.org
> FreeBSD committer
>