netdev - Re: iptables: ensure number of counters is >0 in do

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150519231950.GA30845@breakpoint.cc>
Date:	Wed, 20 May 2015 01:19:50 +0200
From:	Florian Westphal <fw@...len.de>
To:	Dave Jones <davej@...emonkey.org.uk>
Cc:	netfilter-devel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: iptables: ensure number of counters is >0 in do_replace()

Dave Jones <davej@...emonkey.org.uk> wrote:
> After improving setsockopt() coverage in trinity, I started triggering
> vmalloc failures pretty reliably from this code path:
> 
> warn_alloc_failed+0xe9/0x140
> __vmalloc_node_range+0x1be/0x270
> vzalloc+0x4b/0x50
> __do_replace+0x52/0x260 [ip_tables]
> do_ipt_set_ctl+0x15d/0x1d0 [ip_tables]
> nf_setsockopt+0x65/0x90
> ip_setsockopt+0x61/0xa0
> raw_setsockopt+0x16/0x60
> sock_common_setsockopt+0x14/0x20
> SyS_setsockopt+0x71/0xd0
> 
> It turns out we don't validate that the num_counters field in the
> struct we pass in from userspace is initialized.
> 
> Signed-off-by: Dave Jones <davej@...emonkey.org.uk>
> 
> diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
> index c69db7fa25ee..12a33d178614 100644
> --- a/net/ipv4/netfilter/ip_tables.c
> +++ b/net/ipv4/netfilter/ip_tables.c
> @@ -1262,6 +1262,9 @@ do_replace(struct net *net, const void __user *user, unsigned int len)
>  	/* overflow check */
>  	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
>  		return -ENOMEM;
> +	if (tmp.num_counters == 0)
> +		return -EINVAL;
> +

Good catch.  Due to iptables wonderful copy-paste programming model,
this also needs fixing in compat_do_replace, ip6tables, arbtables and
ebtables (8 different places, ick).
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html