From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Jianlin Shi <jishi@redhat.com>,
Sabrina Dubroca <sd@queasysnail.net>,
Stefano Brivio <sbrivio@redhat.com>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 3.18 19/21] net: ipv4: dont allow setting net.ipv4.route.min_pmtu below 68
Date: Fri, 9 Mar 2018 16:18:41 -0800 [thread overview]
Message-ID: <20180310001802.292238473@linuxfoundation.org> (raw)
In-Reply-To: <20180310001801.045114869@linuxfoundation.org>
3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sabrina Dubroca <sd@queasysnail.net>
[ Upstream commit c7272c2f1229125f74f22dcdd59de9bbd804f1c8 ]
According to RFC 1191 sections 3 and 4, ICMP frag-needed messages
indicating an MTU below 68 should be rejected:
A host MUST never reduce its estimate of the Path MTU below 68
octets.
and (talking about ICMP frag-needed's Next-Hop MTU field):
This field will never contain a value less than 68, since every
router "must be able to forward a datagram of 68 octets without
fragmentation".
Furthermore, by letting net.ipv4.route.min_pmtu be set to negative
values, we can end up with a very large PMTU when (-1) is cast into u32.
Let's also make ip_rt_min_pmtu a u32, since it's only ever compared to
unsigned ints.
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/route.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -122,9 +122,11 @@ static int ip_rt_redirect_silence __read
static int ip_rt_error_cost __read_mostly = HZ;
static int ip_rt_error_burst __read_mostly = 5 * HZ;
static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
-static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
+static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
static int ip_rt_min_advmss __read_mostly = 256;
+static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
+
/*
* Interface to generic destination cache.
*/
@@ -2629,7 +2631,8 @@ static struct ctl_table ipv4_route_table
.data = &ip_rt_min_pmtu,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &ip_min_valid_pmtu,
},
{
.procname = "min_adv_mss",
next prev parent reply other threads:[~2018-03-10 0:18 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-10 0:18 [PATCH 3.18 00/21] 3.18.99-stable review Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 01/21] tpm_i2c_infineon: fix potential buffer overruns caused by bit glitches on the bus Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 02/21] tpm_i2c_nuvoton: " Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 03/21] ALSA: usb-audio: Add a quirck for B&W PX headphones Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 04/21] cpufreq: s3c24xx: Fix broken s3c_cpufreq_init() Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 05/21] ARM: mvebu: Fix broken PL310_ERRATA_753970 selects Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 06/21] net: fec: introduce fec_ptp_stop and use in probe fail path Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 07/21] leds: do not overflow sysfs buffer in led_trigger_show Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 08/21] bridge: check brport attr show in brport_show Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 09/21] hdlc_ppp: carrier detect ok, dont turn off negotiation Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 10/21] ipv6 sit: work around bogus gcc-8 -Wrestrict warning Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 11/21] net: fix race on decreasing number of TX queues Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 12/21] netlink: ensure to loop over all netns in genlmsg_multicast_allns() Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 13/21] ppp: prevent unregistered channels from connecting to PPP units Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 14/21] udplite: fix partial checksum initialization Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 15/21] sctp: fix dst refcnt leak in sctp_v6_get_dst() Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 16/21] s390/qeth: fix SETIP command handling Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 17/21] s390/qeth: fix IPA command submission race Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 18/21] sctp: verify size of a new chunk in _sctp_make_chunk() Greg Kroah-Hartman
2018-03-10 0:18 ` Greg Kroah-Hartman [this message]
2018-03-10 0:18 ` [PATCH 3.18 20/21] fib_semantics: Dont match route with mismatching tclassid Greg Kroah-Hartman
2018-03-10 0:18 ` [PATCH 3.18 21/21] dm io: fix duplicate bio completion due to missing ref count Greg Kroah-Hartman
2018-03-10 5:17 ` [PATCH 3.18 00/21] 3.18.99-stable review Shuah Khan
2018-03-10 6:19 ` kernelci.org bot
2018-03-10 15:42 ` Guenter Roeck
2018-03-10 15:51 ` Harsh Shandilya
2018-03-10 19:48 ` Greg Kroah-Hartman
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