2014-06-30 17:05:04

by Kees Cook

[permalink] [raw]
Subject: Re: net/netfilter/xt_LOG.c:43: error: format not a string literal and no format arguments

On Sat, Jun 28, 2014 at 7:07 AM, Fengguang Wu <[email protected]> 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.

-Kees

> 6939c33a Richard Weinberger 2012-02-10 44 return XT_CONTINUE;
> 6939c33a Richard Weinberger 2012-02-10 45 }
> 6939c33a Richard Weinberger 2012-02-10 46
> 6939c33a Richard Weinberger 2012-02-10 47 static int log_tg_check(const struct xt_tgchk_param *par)
> 6939c33a Richard Weinberger 2012-02-10 48 {
> 6939c33a Richard Weinberger 2012-02-10 49 const struct xt_log_info *loginfo = par->targinfo;
> 6939c33a Richard Weinberger 2012-02-10 50
> 6939c33a Richard Weinberger 2012-02-10 51 if (par->family != NFPROTO_IPV4 && par->family != NFPROTO_IPV6)
>
> ---
> 0-DAY kernel build testing backend Open Source Technology Center
> http://lists.01.org/mailman/listinfo/kbuild Intel Corporation



--
Kees Cook
Chrome OS Security


2014-06-30 17:39:52

by Pablo Neira Ayuso

[permalink] [raw]
Subject: Re: net/netfilter/xt_LOG.c:43: error: format not a string literal and no format arguments

On Mon, Jun 30, 2014 at 10:05:01AM -0700, Kees Cook wrote:
> On Sat, Jun 28, 2014 at 7:07 AM, Fengguang Wu <[email protected]> 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

2014-06-30 18:06:25

by Kees Cook

[permalink] [raw]
Subject: Re: net/netfilter/xt_LOG.c:43: error: format not a string literal and no format arguments

On Mon, Jun 30, 2014 at 10:39 AM, Pablo Neira Ayuso <[email protected]> wrote:
> On Mon, Jun 30, 2014 at 10:05:01AM -0700, Kees Cook wrote:
>> On Sat, Jun 28, 2014 at 7:07 AM, Fengguang Wu <[email protected]> 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

Ah-ha! Perfect, thanks! :)

-Kees

--
Kees Cook
Chrome OS Security