diff options
| author | Alice Mikityanska <alice@isovalent.com> | 2026-09-01 22:57:14 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-09-07 17:13:55 -0700 |
| commit | 199271ebc71c1e0913b2fad988a7bff330a8828a (patch) | |
| tree | 564428a3f825d60a46933e9db9e603dcd0f7c6c8 /include/net | |
| parent | 18a9a4342136c5ae954b37d961c374d369615de2 (diff) | |
net: ipv6: Clamp to IP6_MAX_MTU in ip6_dst_mtu_maybe_forward
Commit 427faee167bc ("net: ipv6: introduce ip6_dst_mtu_maybe_forward")
dropped the IP6_MAX_MTU clamp that used to be present in ip6_mtu(). A
similar IPv4 commit ac6627a28dbf ("net: ipv4: Consolidate ipv4_mtu and
ip_dst_mtu_maybe_forward") preserves the IP_MAX_MTU clamp.
Restore the upper bound in the IPv6 flow to avoid potential 16-bit
overflows in forwarding paths.
Fixes: 427faee167bc ("net: ipv6: introduce ip6_dst_mtu_maybe_forward")
Signed-off-by: Alice Mikityanska <alice@isovalent.com>
Suggested-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260901195714.673548-5-alice.kernel@fastmail.im
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/ip6_route.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index c69f1c871922..b9e8d2b759e9 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -384,6 +384,8 @@ static inline unsigned int ip6_dst_mtu_maybe_forward(const struct dst_entry *dst rcu_read_unlock(); out: + mtu = min_t(unsigned int, mtu, IP6_MAX_MTU); + return mtu - lwtunnel_headroom(dst->lwtstate, mtu); } |