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authorEric Dumazet <edumazet@google.com>2017-12-11 07:17:39 -0800
committerDavid S. Miller <davem@davemloft.net>2017-12-13 13:13:58 -0500
commitb5476022bbada3764609368f03329ca287528dc8 (patch)
tree93662637d298a843940b42d54ca36326f456db95 /net/ipv4/devinet.c
parentipv6: mcast: better catch silly mtu values (diff)
downloadlinux-dev-b5476022bbada3764609368f03329ca287528dc8.tar.xz
linux-dev-b5476022bbada3764609368f03329ca287528dc8.zip
ipv4: igmp: guard against silly MTU values
IPv4 stack reacts to changes to small MTU, by disabling itself under RTNL. But there is a window where threads not using RTNL can see a wrong device mtu. This can lead to surprises, in igmp code where it is assumed the mtu is suitable. Fix this by reading device mtu once and checking IPv4 minimal MTU. This patch adds missing IPV4_MIN_MTU define, to not abuse ETH_MIN_MTU anymore. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/devinet.c')
-rw-r--r--net/ipv4/devinet.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index a4573bccd6da..7a93359fbc72 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1428,7 +1428,7 @@ skip:
static bool inetdev_valid_mtu(unsigned int mtu)
{
- return mtu >= 68;
+ return mtu >= IPV4_MIN_MTU;
}
static void inetdev_send_gratuitous_arp(struct net_device *dev,