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authorIdo Schimmel <idosch@nvidia.com>2024-07-15 16:23:54 +0200
committerPaolo Abeni <pabeni@redhat.com>2024-07-18 11:11:02 +0200
commitf036e68212c11e5a7edbb59b5e25299341829485 (patch)
tree68c3e6b65de6ef407fa9eecb7845f99ba2041a3e /net/ipv4
parentipv4: Fix incorrect TOS in route get reply (diff)
downloadlinux-f036e68212c11e5a7edbb59b5e25299341829485.tar.xz
linux-f036e68212c11e5a7edbb59b5e25299341829485.zip
ipv4: Fix incorrect TOS in fibmatch route get reply
The TOS value that is returned to user space in the route get reply is the one with which the lookup was performed ('fl4->flowi4_tos'). This is fine when the matched route is configured with a TOS as it would not match if its TOS value did not match the one with which the lookup was performed. However, matching on TOS is only performed when the route's TOS is not zero. It is therefore possible to have the kernel incorrectly return a non-zero TOS: # ip link add name dummy1 up type dummy # ip address add 192.0.2.1/24 dev dummy1 # ip route get fibmatch 192.0.2.2 tos 0xfc 192.0.2.0/24 tos 0x1c dev dummy1 proto kernel scope link src 192.0.2.1 Fix by instead returning the DSCP field from the FIB result structure which was populated during the route lookup. Output after the patch: # ip link add name dummy1 up type dummy # ip address add 192.0.2.1/24 dev dummy1 # ip route get fibmatch 192.0.2.2 tos 0xfc 192.0.2.0/24 dev dummy1 proto kernel scope link src 192.0.2.1 Extend the existing selftests to not only verify that the correct route is returned, but that it is also returned with correct "tos" value (or without it). Fixes: b61798130f1b ("net: ipv4: RTM_GETROUTE: return matched fib result when requested") Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/route.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 82b8fe8faeb7..5090912533d6 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -3331,7 +3331,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
fri.tb_id = table_id;
fri.dst = res.prefix;
fri.dst_len = res.prefixlen;
- fri.dscp = inet_dsfield_to_dscp(fl4.flowi4_tos);
+ fri.dscp = res.dscp;
fri.type = rt->rt_type;
fri.offload = 0;
fri.trap = 0;