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| author | Guillaume Nault <gnault@redhat.com> | 2020-11-26 19:09:22 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-12-08 10:17:33 +0100 |
| commit | 2b768247675ba7183f29a6046a10218ab5d910e1 (patch) | |
| tree | fbc9fc8c130c4a9c4fcd8afa5f0ae80d1eb0fb66 /net | |
| parent | 5e2cca19f18cbbe9e60c22121ac276f8bf6ab728 (diff) | |
| download | linux-2b768247675ba7183f29a6046a10218ab5d910e1.tar.gz linux-2b768247675ba7183f29a6046a10218ab5d910e1.tar.bz2 linux-2b768247675ba7183f29a6046a10218ab5d910e1.zip | |
ipv4: Fix tos mask in inet_rtm_getroute()
[ Upstream commit 1ebf179037cb46c19da3a9c1e2ca16e7a754b75e ]
When inet_rtm_getroute() was converted to use the RCU variants of
ip_route_input() and ip_route_output_key(), the TOS parameters
stopped being masked with IPTOS_RT_MASK before doing the route lookup.
As a result, "ip route get" can return a different route than what
would be used when sending real packets.
For example:
$ ip route add 192.0.2.11/32 dev eth0
$ ip route add unreachable 192.0.2.11/32 tos 2
$ ip route get 192.0.2.11 tos 2
RTNETLINK answers: No route to host
But, packets with TOS 2 (ECT(0) if interpreted as an ECN bit) would
actually be routed using the first route:
$ ping -c 1 -Q 2 192.0.2.11
PING 192.0.2.11 (192.0.2.11) 56(84) bytes of data.
64 bytes from 192.0.2.11: icmp_seq=1 ttl=64 time=0.173 ms
--- 192.0.2.11 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.173/0.173/0.173/0.000 ms
This patch re-applies IPTOS_RT_MASK in inet_rtm_getroute(), to
return results consistent with real route lookups.
Fixes: 3765d35ed8b9 ("net: ipv4: Convert inet_rtm_getroute to rcu versions of route lookup")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/b2d237d08317ca55926add9654a48409ac1b8f5b.1606412894.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/route.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 87854642e0b6..be7383d139c1 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2788,7 +2788,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, memset(&fl4, 0, sizeof(fl4)); fl4.daddr = dst; fl4.saddr = src; - fl4.flowi4_tos = rtm->rtm_tos; + fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK; fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; fl4.flowi4_mark = mark; fl4.flowi4_uid = uid; @@ -2807,8 +2807,9 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, skb->protocol = htons(ETH_P_IP); skb->dev = dev; skb->mark = mark; - err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, - dev, &res); + err = ip_route_input_rcu(skb, dst, src, + rtm->rtm_tos & IPTOS_RT_MASK, dev, + &res); rt = skb_rtable(skb); if (err == 0 && rt->dst.error) |