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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Jonathon Reinhart <Jonathon.Reinhart@gmail.com>,
	"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.12 02/17] netfilter: conntrack: Make global sysctls readonly in non-init netns
Date: Wed,  5 May 2021 14:05:57 +0200	[thread overview]
Message-ID: <20210505112325.034188957@linuxfoundation.org> (raw)
In-Reply-To: <20210505112324.956720416@linuxfoundation.org>

From: Jonathon Reinhart <jonathon.reinhart@gmail.com>

commit 2671fa4dc0109d3fb581bc3078fdf17b5d9080f6 upstream.

These sysctls point to global variables:
- NF_SYSCTL_CT_MAX (&nf_conntrack_max)
- NF_SYSCTL_CT_EXPECT_MAX (&nf_ct_expect_max)
- NF_SYSCTL_CT_BUCKETS (&nf_conntrack_htable_size_user)

Because their data pointers are not updated to point to per-netns
structures, they must be marked read-only in a non-init_net ns.
Otherwise, changes in any net namespace are reflected in (leaked into)
all other net namespaces. This problem has existed since the
introduction of net namespaces.

The current logic marks them read-only only if the net namespace is
owned by an unprivileged user (other than init_user_ns).

Commit d0febd81ae77 ("netfilter: conntrack: re-visit sysctls in
unprivileged namespaces") "exposes all sysctls even if the namespace is
unpriviliged." Since we need to mark them readonly in any case, we can
forego the unprivileged user check altogether.

Fixes: d0febd81ae77 ("netfilter: conntrack: re-visit sysctls in unprivileged namespaces")
Signed-off-by: Jonathon Reinhart <Jonathon.Reinhart@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/netfilter/nf_conntrack_standalone.c |   10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -1060,16 +1060,10 @@ static int nf_conntrack_standalone_init_
 	nf_conntrack_standalone_init_dccp_sysctl(net, table);
 	nf_conntrack_standalone_init_gre_sysctl(net, table);
 
-	/* Don't allow unprivileged users to alter certain sysctls */
-	if (net->user_ns != &init_user_ns) {
+	/* Don't allow non-init_net ns to alter global sysctls */
+	if (!net_eq(&init_net, net)) {
 		table[NF_SYSCTL_CT_MAX].mode = 0444;
 		table[NF_SYSCTL_CT_EXPECT_MAX].mode = 0444;
-		table[NF_SYSCTL_CT_HELPER].mode = 0444;
-#ifdef CONFIG_NF_CONNTRACK_EVENTS
-		table[NF_SYSCTL_CT_EVENTS].mode = 0444;
-#endif
-		table[NF_SYSCTL_CT_BUCKETS].mode = 0444;
-	} else if (!net_eq(&init_net, net)) {
 		table[NF_SYSCTL_CT_BUCKETS].mode = 0444;
 	}
 



  parent reply	other threads:[~2021-05-05 12:10 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-05 12:05 [PATCH 5.12 00/17] 5.12.2-rc1 review Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.12 01/17] mips: Do not include hi and lo in clobber list for R6 Greg Kroah-Hartman
2021-05-05 12:05 ` Greg Kroah-Hartman [this message]
2021-05-05 12:05 ` [PATCH 5.12 03/17] net: usb: ax88179_178a: initialize local variables before use Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.12 04/17] drm/i915: Disable runtime power management during shutdown Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 05/17] bpf: Fix masking negation logic upon negative dst register Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 06/17] bpf: Fix leakage of uninitialized bpf stack under speculation Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 07/17] net: qrtr: Avoid potential use after free in MHI send Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 08/17] ovl: fix leaked dentry Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 09/17] ovl: allow upperdir inside lowerdir Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 10/17] ALSA: usb-audio: Add MIDI quirk for Vox ToneLab EX Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 11/17] ALSA: usb-audio: Fix implicit sync clearance at stopping stream Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 12/17] USB: Add LPM quirk for Lenovo ThinkPad USB-C Dock Gen2 Ethernet Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 13/17] USB: Add reset-resume quirk for WD19s Realtek Hub Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 14/17] ASoC: ak4458: Add MODULE_DEVICE_TABLE Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 15/17] ASoC: ak5558: " Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 16/17] platform/x86: thinkpad_acpi: Correct thermal sensor allocation Greg Kroah-Hartman
2021-05-05 12:06 ` [PATCH 5.12 17/17] perf/core: Fix unconditional security_locked_down() call Greg Kroah-Hartman
2021-05-05 17:52 ` [PATCH 5.12 00/17] 5.12.2-rc1 review Fox Chen
2021-05-05 19:09 ` Naresh Kamboju
2021-05-05 19:44 ` Florian Fainelli
2021-05-06  1:59 ` Guenter Roeck

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