Re: net/netfilter/xt_LOG.c:43: error: format not a string literal and no format arguments
From: Pablo Neira Ayuso
Date: Mon Jun 30 2014 - 13:39:55 EST
On Mon, Jun 30, 2014 at 10:05:01AM -0700, Kees Cook wrote:
> On Sat, Jun 28, 2014 at 7:07 AM, Fengguang Wu <fengguang.wu@xxxxxxxxx> wrote:
> > tree: git://internal_merge_and_test_tree devel-ant-um-201406281943
> > head: fbb9065499371b760e0543f2ff66fde4778b46ae
> > commit: 2af37708d3ce0ae78898051ea76bc7c5f683171c [30/31] Merge 'nftables/master' into devel-ant-um-201406281943
> > config: make ARCH=avr32 atngw100_defconfig
> >
> > All error/warnings:
> >
> > net/netfilter/xt_LOG.c: In function 'log_tg':
> >>> net/netfilter/xt_LOG.c:43: error: format not a string literal and no format arguments
> >
> > vim +43 net/netfilter/xt_LOG.c
> >
> > 6939c33a Richard Weinberger 2012-02-10 27 #include <linux/netfilter/xt_LOG.h>
> > 6939c33a Richard Weinberger 2012-02-10 28 #include <linux/netfilter_ipv6/ip6_tables.h>
> > 6939c33a Richard Weinberger 2012-02-10 29 #include <net/netfilter/nf_log.h>
> > 6939c33a Richard Weinberger 2012-02-10 30
> > 6939c33a Richard Weinberger 2012-02-10 31 static unsigned int
> > 6939c33a Richard Weinberger 2012-02-10 32 log_tg(struct sk_buff *skb, const struct xt_action_param *par)
> > 6939c33a Richard Weinberger 2012-02-10 33 {
> > 6939c33a Richard Weinberger 2012-02-10 34 const struct xt_log_info *loginfo = par->targinfo;
> > 6939c33a Richard Weinberger 2012-02-10 35 struct nf_loginfo li;
> > 8cdb46da Hans Schillstrom 2013-05-15 36 struct net *net = dev_net(par->in ? par->in : par->out);
> > 6939c33a Richard Weinberger 2012-02-10 37
> > 6939c33a Richard Weinberger 2012-02-10 38 li.type = NF_LOG_TYPE_LOG;
> > 6939c33a Richard Weinberger 2012-02-10 39 li.u.log.level = loginfo->level;
> > 6939c33a Richard Weinberger 2012-02-10 40 li.u.log.logflags = loginfo->logflags;
> > 6939c33a Richard Weinberger 2012-02-10 41
> > fab4085f Pablo Neira Ayuso 2014-06-18 42 nf_log_packet(net, par->family, par->hooknum, skb, par->in, par->out,
> > fab4085f Pablo Neira Ayuso 2014-06-18 @43 &li, loginfo->prefix);
>
> This needs to be:
>
> nf_log_packet(net, par->family, par->hooknum, skb, par->in, par->out,
> &li, "%s", loginfo->prefix);
>
> Without this, any format strings contained by "prefix" can get
> processed and leak kernel contents.
http://git.kernel.org/cgit/linux/kernel/git/pablo/nf-next.git/commit/?id=ca1aa54f272d47bec77baa292f803df7a81f966b
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