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ip_tunnel: Clamp MTU to bounds on new link
[ Upstream commit24fc79798b
] Otherwise, it's possible to specify invalid MTU values directly on creation of a link (via 'ip link add'). This is already prevented on subsequent MTU changes by commitb96f9afee4
("ipv4/6: use core net MTU range checking"). Fixes:c544193214
("GRE: Refactor GRE tunneling code.") Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Acked-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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parent
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commit
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1 changed files with 7 additions and 1 deletions
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@ -1103,8 +1103,14 @@ int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
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eth_hw_addr_random(dev);
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mtu = ip_tunnel_bind_dev(dev);
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if (!tb[IFLA_MTU])
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if (tb[IFLA_MTU]) {
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unsigned int max = 0xfff8 - dev->hard_header_len - nt->hlen;
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dev->mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU,
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(unsigned int)(max - sizeof(struct iphdr)));
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} else {
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dev->mtu = mtu;
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}
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ip_tunnel_add(itn, nt);
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out:
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