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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Dmitry Vyukov <dvyukov@google.com>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.15 111/189] netfilter: x_tables: fix pointer
 leaks to userspace
Thread-Topic: [PATCH AUTOSEL for 4.15 111/189] netfilter: x_tables: fix
 pointer leaks to userspace
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Date:   Mon, 9 Apr 2018 00:18:13 +0000
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From: Dmitry Vyukov <dvyukov@google.com>

[ Upstream commit 1e98ffea5a8935ec040ab72299e349cb44b8defd ]

Several netfilter matches and targets put kernel pointers into
info objects, but don't set usersize in descriptors.
This leads to kernel pointer leaks if a match/target is set
and then read back to userspace.

Properly set usersize for these matches/targets.

Found with manual code inspection.

Fixes: ec2318904965 ("xtables: extend matches and targets with .usersize")
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 net/netfilter/xt_IDLETIMER.c | 1 +
 net/netfilter/xt_LED.c       | 1 +
 net/netfilter/xt_limit.c     | 3 +--
 net/netfilter/xt_nfacct.c    | 1 +
 net/netfilter/xt_statistic.c | 1 +
 5 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c
index 18b7412ab99a..1ac6600bfafd 100644
--- a/net/netfilter/xt_IDLETIMER.c
+++ b/net/netfilter/xt_IDLETIMER.c
@@ -255,6 +255,7 @@ static struct xt_target idletimer_tg __read_mostly =3D =
{
 	.family		=3D NFPROTO_UNSPEC,
 	.target		=3D idletimer_tg_target,
 	.targetsize     =3D sizeof(struct idletimer_tg_info),
+	.usersize	=3D offsetof(struct idletimer_tg_info, timer),
 	.checkentry	=3D idletimer_tg_checkentry,
 	.destroy        =3D idletimer_tg_destroy,
 	.me		=3D THIS_MODULE,
diff --git a/net/netfilter/xt_LED.c b/net/netfilter/xt_LED.c
index 18d3af5e1098..0fb2133165aa 100644
--- a/net/netfilter/xt_LED.c
+++ b/net/netfilter/xt_LED.c
@@ -198,6 +198,7 @@ static struct xt_target led_tg_reg __read_mostly =3D {
 	.family		=3D NFPROTO_UNSPEC,
 	.target		=3D led_tg,
 	.targetsize	=3D sizeof(struct xt_led_info),
+	.usersize	=3D offsetof(struct xt_led_info, internal_data),
 	.checkentry	=3D led_tg_check,
 	.destroy	=3D led_tg_destroy,
 	.me		=3D THIS_MODULE,
diff --git a/net/netfilter/xt_limit.c b/net/netfilter/xt_limit.c
index d27b5f1ea619..61403b77361c 100644
--- a/net/netfilter/xt_limit.c
+++ b/net/netfilter/xt_limit.c
@@ -193,9 +193,8 @@ static struct xt_match limit_mt_reg __read_mostly =3D {
 	.compatsize       =3D sizeof(struct compat_xt_rateinfo),
 	.compat_from_user =3D limit_mt_compat_from_user,
 	.compat_to_user   =3D limit_mt_compat_to_user,
-#else
-	.usersize         =3D offsetof(struct xt_rateinfo, prev),
 #endif
+	.usersize         =3D offsetof(struct xt_rateinfo, prev),
 	.me               =3D THIS_MODULE,
 };
=20
diff --git a/net/netfilter/xt_nfacct.c b/net/netfilter/xt_nfacct.c
index cc0518fe598e..6f92d25590a8 100644
--- a/net/netfilter/xt_nfacct.c
+++ b/net/netfilter/xt_nfacct.c
@@ -62,6 +62,7 @@ static struct xt_match nfacct_mt_reg __read_mostly =3D {
 	.match      =3D nfacct_mt,
 	.destroy    =3D nfacct_mt_destroy,
 	.matchsize  =3D sizeof(struct xt_nfacct_match_info),
+	.usersize   =3D offsetof(struct xt_nfacct_match_info, nfacct),
 	.me         =3D THIS_MODULE,
 };
=20
diff --git a/net/netfilter/xt_statistic.c b/net/netfilter/xt_statistic.c
index 11de55e7a868..8710fdba2ae2 100644
--- a/net/netfilter/xt_statistic.c
+++ b/net/netfilter/xt_statistic.c
@@ -84,6 +84,7 @@ static struct xt_match xt_statistic_mt_reg __read_mostly =
=3D {
 	.checkentry =3D statistic_mt_check,
 	.destroy    =3D statistic_mt_destroy,
 	.matchsize  =3D sizeof(struct xt_statistic_info),
+	.usersize   =3D offsetof(struct xt_statistic_info, master),
 	.me         =3D THIS_MODULE,
 };
=20
--=20
2.15.1