kernel/linux.git/include/net/ip_tunnels.h, branch v5.10.258

net/ip6_tunnel: Prevent perpetual tunnel growth

2025-10-29T13:01:19+00:00

[ Upstream commit 21f4d45eba0b2dcae5dbc9e5e0ad08735c993f16 ] Similarly to ipv4 tunnel, ipv6 version updates dev->needed_headroom, too. While ipv4 tunnel headroom adjustment growth was limited in commit 5ae1e9922bbd ("net: ip_tunnel: prevent perpetual headroom growth"), ipv6 tunnel yet increases the headroom without any ceiling. Reflect ipv4 tunnel headroom adjustment limit on ipv6 version. Credits to Francesco Ruggeri, who was originally debugging this issue and wrote local Arista-specific patch and a reproducer. Fixes: 8eb30be0352d ("ipv6: Create ip6_tnl_xmit") Cc: Florian Westphal Cc: Francesco Ruggeri Signed-off-by: Dmitry Safonov Link: https://patch.msgid.link/20251009-ip6_tunnel-headroom-v2-1-8e4dbd8f7e35@arista.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv4: ip_tunnel: Fix suspicious RCU usage warning in ip_tunnel_init_flow()

2024-11-08T15:22:01+00:00

[ Upstream commit ad4a3ca6a8e886f6491910a3ae5d53595e40597d ] There are code paths from which the function is called without holding the RCU read lock, resulting in a suspicious RCU usage warning [1]. Fix by using l3mdev_master_upper_ifindex_by_index() which will acquire the RCU read lock before calling l3mdev_master_upper_ifindex_by_index_rcu(). [1] WARNING: suspicious RCU usage 6.12.0-rc3-custom-gac8f72681cf2 #141 Not tainted ----------------------------- net/core/dev.c:876 RCU-list traversed in non-reader section!! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by ip/361: #0: ffffffff86fc7cb0 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x377/0xf60 stack backtrace: CPU: 3 UID: 0 PID: 361 Comm: ip Not tainted 6.12.0-rc3-custom-gac8f72681cf2 #141 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack_lvl+0xba/0x110 lockdep_rcu_suspicious.cold+0x4f/0xd6 dev_get_by_index_rcu+0x1d3/0x210 l3mdev_master_upper_ifindex_by_index_rcu+0x2b/0xf0 ip_tunnel_bind_dev+0x72f/0xa00 ip_tunnel_newlink+0x368/0x7a0 ipgre_newlink+0x14c/0x170 __rtnl_newlink+0x1173/0x19c0 rtnl_newlink+0x6c/0xa0 rtnetlink_rcv_msg+0x3cc/0xf60 netlink_rcv_skb+0x171/0x450 netlink_unicast+0x539/0x7f0 netlink_sendmsg+0x8c1/0xd80 ____sys_sendmsg+0x8f9/0xc20 ___sys_sendmsg+0x197/0x1e0 __sys_sendmsg+0x122/0x1f0 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: db53cd3d88dc ("net: Handle l3mdev in ip_tunnel_init_flow") Signed-off-by: Ido Schimmel Reviewed-by: David Ahern Link: https://patch.msgid.link/20241022063822.462057-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: Handle l3mdev in ip_tunnel_init_flow

2024-10-17T13:08:38+00:00

commit db53cd3d88dc328dea2e968c9c8d3b4294a8a674 upstream. Ido reported that the commit referenced in the Fixes tag broke a gre use case with dummy devices. Add a check to ip_tunnel_init_flow to see if the oif is an l3mdev port and if so set the oif to 0 to avoid the oif comparison in fib_lookup_good_nhc. Fixes: 40867d74c374 ("net: Add l3mdev index to flow struct and avoid oif reset for port devices") Reported-by: Ido Schimmel Signed-off-by: David Ahern Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

geneve: Fix incorrect inner network header offset when innerprotoinherit is set

2024-10-17T13:07:42+00:00

[ Upstream commit c6ae073f5903f6c6439d0ac855836a4da5c0a701 ] When innerprotoinherit is set, the tunneled packets do not have an inner Ethernet header. Change 'maclen' to not always assume the header length is ETH_HLEN, as there might not be a MAC header. This resolves issues with drivers (e.g. mlx5, in mlx5e_tx_tunnel_accel()) who rely on the skb inner network header offset to be correct, and use it for TX offloads. Fixes: d8a6213d70ac ("geneve: fix header validation in geneve[6]_xmit_skb") Signed-off-by: Gal Pressman Signed-off-by: Tariq Toukan Reviewed-by: Wojciech Drewek Signed-off-by: David S. Miller Stable-dep-of: c471236b2359 ("bareudp: Pull inner IP header on xmit.") Signed-off-by: Sasha Levin

geneve: fix header validation in geneve[6]_xmit_skb

2024-05-02T14:23:34+00:00

[ Upstream commit d8a6213d70accb403b82924a1c229e733433a5ef ] syzbot is able to trigger an uninit-value in geneve_xmit() [1] Problem : While most ip tunnel helpers (like ip_tunnel_get_dsfield()) uses skb_protocol(skb, true), pskb_inet_may_pull() is only using skb->protocol. If anything else than ETH_P_IPV6 or ETH_P_IP is found in skb->protocol, pskb_inet_may_pull() does nothing at all. If a vlan tag was provided by the caller (af_packet in the syzbot case), the network header might not point to the correct location, and skb linear part could be smaller than expected. Add skb_vlan_inet_prepare() to perform a complete mac validation. Use this in geneve for the moment, I suspect we need to adopt this more broadly. v4 - Jakub reported v3 broke l2_tos_ttl_inherit.sh selftest - Only call __vlan_get_protocol() for vlan types. Link: https://lore.kernel.org/netdev/20240404100035.3270a7d5@kernel.org/ v2,v3 - Addressed Sabrina comments on v1 and v2 Link: https://lore.kernel.org/netdev/Zg1l9L2BNoZWZDZG@hog/ [1] BUG: KMSAN: uninit-value in geneve_xmit_skb drivers/net/geneve.c:910 [inline] BUG: KMSAN: uninit-value in geneve_xmit+0x302d/0x5420 drivers/net/geneve.c:1030 geneve_xmit_skb drivers/net/geneve.c:910 [inline] geneve_xmit+0x302d/0x5420 drivers/net/geneve.c:1030 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3547 __dev_queue_xmit+0x348d/0x52c0 net/core/dev.c:4335 dev_queue_xmit include/linux/netdevice.h:3091 [inline] packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3081 [inline] packet_sendmsg+0x8bb0/0x9ef0 net/packet/af_packet.c:3113 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 __sys_sendto+0x685/0x830 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0x125/0x1d0 net/socket.c:2199 do_syscall_64+0xd5/0x1f0 entry_SYSCALL_64_after_hwframe+0x6d/0x75 Uninit was created at: slab_post_alloc_hook mm/slub.c:3804 [inline] slab_alloc_node mm/slub.c:3845 [inline] kmem_cache_alloc_node+0x613/0xc50 mm/slub.c:3888 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577 __alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1318 [inline] alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6504 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2795 packet_alloc_skb net/packet/af_packet.c:2930 [inline] packet_snd net/packet/af_packet.c:3024 [inline] packet_sendmsg+0x722d/0x9ef0 net/packet/af_packet.c:3113 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 __sys_sendto+0x685/0x830 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0x125/0x1d0 net/socket.c:2199 do_syscall_64+0xd5/0x1f0 entry_SYSCALL_64_after_hwframe+0x6d/0x75 CPU: 0 PID: 5033 Comm: syz-executor346 Not tainted 6.9.0-rc1-syzkaller-00005-g928a87efa423 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Fixes: d13f048dd40e ("net: geneve: modify IP header check in geneve6_xmit_skb and geneve_xmit_skb") Reported-by: syzbot+9ee20ec1de7b3168db09@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/000000000000d19c3a06152f9ee4@google.com/ Signed-off-by: Eric Dumazet Cc: Phillip Potter Cc: Sabrina Dubroca Reviewed-by: Sabrina Dubroca Reviewed-by: Phillip Potter Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

ip_tunnels: use DEV_STATS_INC()

2023-09-19T10:20:27+00:00

[ Upstream commit 9b271ebaf9a2c5c566a54bc6cd915962e8241130 ] syzbot/KCSAN reported data-races in iptunnel_xmit_stats() [1] This can run from multiple cpus without mutual exclusion. Adopt SMP safe DEV_STATS_INC() to update dev->stats fields. [1] BUG: KCSAN: data-race in iptunnel_xmit / iptunnel_xmit read-write to 0xffff8881353df170 of 8 bytes by task 30263 on cpu 1: iptunnel_xmit_stats include/net/ip_tunnels.h:493 [inline] iptunnel_xmit+0x432/0x4a0 net/ipv4/ip_tunnel_core.c:87 ip_tunnel_xmit+0x1477/0x1750 net/ipv4/ip_tunnel.c:831 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4889 [inline] netdev_start_xmit include/linux/netdevice.h:4903 [inline] xmit_one net/core/dev.c:3544 [inline] dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3560 __dev_queue_xmit+0xeee/0x1de0 net/core/dev.c:4340 dev_queue_xmit include/linux/netdevice.h:3082 [inline] __bpf_tx_skb net/core/filter.c:2129 [inline] __bpf_redirect_no_mac net/core/filter.c:2159 [inline] __bpf_redirect+0x723/0x9c0 net/core/filter.c:2182 ____bpf_clone_redirect net/core/filter.c:2453 [inline] bpf_clone_redirect+0x16c/0x1d0 net/core/filter.c:2425 ___bpf_prog_run+0xd7d/0x41e0 kernel/bpf/core.c:1954 __bpf_prog_run512+0x74/0xa0 kernel/bpf/core.c:2195 bpf_dispatcher_nop_func include/linux/bpf.h:1181 [inline] __bpf_prog_run include/linux/filter.h:609 [inline] bpf_prog_run include/linux/filter.h:616 [inline] bpf_test_run+0x15d/0x3d0 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x77b/0xa00 net/bpf/test_run.c:1045 bpf_prog_test_run+0x265/0x3d0 kernel/bpf/syscall.c:3996 __sys_bpf+0x3af/0x780 kernel/bpf/syscall.c:5353 __do_sys_bpf kernel/bpf/syscall.c:5439 [inline] __se_sys_bpf kernel/bpf/syscall.c:5437 [inline] __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5437 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read-write to 0xffff8881353df170 of 8 bytes by task 30249 on cpu 0: iptunnel_xmit_stats include/net/ip_tunnels.h:493 [inline] iptunnel_xmit+0x432/0x4a0 net/ipv4/ip_tunnel_core.c:87 ip_tunnel_xmit+0x1477/0x1750 net/ipv4/ip_tunnel.c:831 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4889 [inline] netdev_start_xmit include/linux/netdevice.h:4903 [inline] xmit_one net/core/dev.c:3544 [inline] dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3560 __dev_queue_xmit+0xeee/0x1de0 net/core/dev.c:4340 dev_queue_xmit include/linux/netdevice.h:3082 [inline] __bpf_tx_skb net/core/filter.c:2129 [inline] __bpf_redirect_no_mac net/core/filter.c:2159 [inline] __bpf_redirect+0x723/0x9c0 net/core/filter.c:2182 ____bpf_clone_redirect net/core/filter.c:2453 [inline] bpf_clone_redirect+0x16c/0x1d0 net/core/filter.c:2425 ___bpf_prog_run+0xd7d/0x41e0 kernel/bpf/core.c:1954 __bpf_prog_run512+0x74/0xa0 kernel/bpf/core.c:2195 bpf_dispatcher_nop_func include/linux/bpf.h:1181 [inline] __bpf_prog_run include/linux/filter.h:609 [inline] bpf_prog_run include/linux/filter.h:616 [inline] bpf_test_run+0x15d/0x3d0 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x77b/0xa00 net/bpf/test_run.c:1045 bpf_prog_test_run+0x265/0x3d0 kernel/bpf/syscall.c:3996 __sys_bpf+0x3af/0x780 kernel/bpf/syscall.c:5353 __do_sys_bpf kernel/bpf/syscall.c:5439 [inline] __se_sys_bpf kernel/bpf/syscall.c:5437 [inline] __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5437 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x0000000000018830 -> 0x0000000000018831 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 30249 Comm: syz-executor.4 Not tainted 6.5.0-syzkaller-11704-g3f86ed6ec0b3 #0 Fixes: 039f50629b7f ("ip_tunnel: Move stats update to iptunnel_xmit()") Reported-by: syzbot Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

ip_tunnels: allow VXLAN/GENEVE to inherit TOS/TTL from VLAN

2023-06-28T08:28:08+00:00

commit 7074732c8faee201a245a6f983008a5789c0be33 upstream. The current code allows for VXLAN and GENEVE to inherit the TOS respective the TTL when skb-protocol is ETH_P_IP or ETH_P_IPV6. However when the payload is VLAN encapsulated, then this inheriting does not work, because the visible skb-protocol is of type ETH_P_8021Q or ETH_P_8021AD. Instead of skb->protocol use skb_protocol(). Signed-off-by: Matthias May Link: https://lore.kernel.org/r/20220721202718.10092-1-matthias.may@westermo.com Signed-off-by: Jakub Kicinski Cc: Nicolas Dichtel Signed-off-by: Greg Kroah-Hartman

ip_gre, ip6_gre: Fix race condition on o_seqno in collect_md mode

2022-05-09T07:05:04+00:00

[ Upstream commit 31c417c948d7f6909cb63f0ac3298f3c38f8ce20 ] As pointed out by Jakub Kicinski, currently using TUNNEL_SEQ in collect_md mode is racy for [IP6]GRE[TAP] devices. Consider the following sequence of events: 1. An [IP6]GRE[TAP] device is created in collect_md mode using "ip link add ... external". "ip" ignores "[o]seq" if "external" is specified, so TUNNEL_SEQ is off, and the device is marked as NETIF_F_LLTX (i.e. it uses lockless TX); 2. Someone sets TUNNEL_SEQ on outgoing skb's, using e.g. bpf_skb_set_tunnel_key() in an eBPF program attached to this device; 3. gre_fb_xmit() or __gre6_xmit() processes these skb's: gre_build_header(skb, tun_hlen, flags, protocol, tunnel_id_to_key32(tun_info->key.tun_id), (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0); ^^^^^^^^^^^^^^^^^ Since we are not using the TX lock (&txq->_xmit_lock), multiple CPUs may try to do this tunnel->o_seqno++ in parallel, which is racy. Fix it by making o_seqno atomic_t. As mentioned by Eric Dumazet in commit b790e01aee74 ("ip_gre: lockless xmit"), making o_seqno atomic_t increases "chance for packets being out of order at receiver" when NETIF_F_LLTX is on. Maybe a better fix would be: 1. Do not ignore "oseq" in external mode. Users MUST specify "oseq" if they want the kernel to allow sequencing of outgoing packets; 2. Reject all outgoing TUNNEL_SEQ packets if the device was not created with "oseq". Unfortunately, that would break userspace. We could now make [IP6]GRE[TAP] devices always NETIF_F_LLTX, but let us do it in separate patches to keep this fix minimal. Suggested-by: Jakub Kicinski Fixes: 77a5196a804e ("gre: add sequence number for collect md mode.") Signed-off-by: Peilin Ye Acked-by: William Tu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

ip_tunnels: Set tunnel option flag when tunnel metadata is present

2020-11-14T00:58:10+00:00

Currently, we may set the tunnel option flag when the size of metadata is zero. For example, we set TUNNEL_GENEVE_OPT in the receive function no matter the geneve option is present or not. As this may result in issues on the tunnel flags consumers, this patch fixes the issue. Related discussion: * https://lore.kernel.org/netdev/1604448694-19351-1-git-send-email-yihung.wei@gmail.com/T/#u Fixes: 256c87c17c53 ("net: check tunnel option type in tunnel flags") Signed-off-by: Yi-Hung Wei Link: https://lore.kernel.org/r/1605053800-74072-1-git-send-email-yihung.wei@gmail.com Signed-off-by: Jakub Kicinski

tunnels: PMTU discovery support for directly bridged IP packets

2020-08-04T20:01:45+00:00

It's currently possible to bridge Ethernet tunnels carrying IP packets directly to external interfaces without assigning them addresses and routes on the bridged network itself: this is the case for UDP tunnels bridged with a standard bridge or by Open vSwitch. PMTU discovery is currently broken with those configurations, because the encapsulation effectively decreases the MTU of the link, and while we are able to account for this using PMTU discovery on the lower layer, we don't have a way to relay ICMP or ICMPv6 messages needed by the sender, because we don't have valid routes to it. On the other hand, as a tunnel endpoint, we can't fragment packets as a general approach: this is for instance clearly forbidden for VXLAN by RFC 7348, section 4.3: VTEPs MUST NOT fragment VXLAN packets. Intermediate routers may fragment encapsulated VXLAN packets due to the larger frame size. The destination VTEP MAY silently discard such VXLAN fragments. The same paragraph recommends that the MTU over the physical network accomodates for encapsulations, but this isn't a practical option for complex topologies, especially for typical Open vSwitch use cases. Further, it states that: Other techniques like Path MTU discovery (see [RFC1191] and [RFC1981]) MAY be used to address this requirement as well. Now, PMTU discovery already works for routed interfaces, we get route exceptions created by the encapsulation device as they receive ICMP Fragmentation Needed and ICMPv6 Packet Too Big messages, and we already rebuild those messages with the appropriate MTU and route them back to the sender. Add the missing bits for bridged cases: - checks in skb_tunnel_check_pmtu() to understand if it's appropriate to trigger a reply according to RFC 1122 section 3.2.2 for ICMP and RFC 4443 section 2.4 for ICMPv6. This function is already called by UDP tunnels - a new function generating those ICMP or ICMPv6 replies. We can't reuse icmp_send() and icmp6_send() as we don't see the sender as a valid destination. This doesn't need to be generic, as we don't cover any other type of ICMP errors given that we only provide an encapsulation function to the sender While at it, make the MTU check in skb_tunnel_check_pmtu() accurate: we might receive GSO buffers here, and the passed headroom already includes the inner MAC length, so we don't have to account for it a second time (that would imply three MAC headers on the wire, but there are just two). This issue became visible while bridging IPv6 packets with 4500 bytes of payload over GENEVE using IPv4 with a PMTU of 4000. Given the 50 bytes of encapsulation headroom, we would advertise MTU as 3950, and we would reject fragmented IPv6 datagrams of 3958 bytes size on the wire. We're exclusively dealing with network MTU here, though, so we could get Ethernet frames up to 3964 octets in that case. v2: - moved skb_tunnel_check_pmtu() to ip_tunnel_core.c (David Ahern) - split IPv4/IPv6 functions (David Ahern) Signed-off-by: Stefano Brivio Reviewed-by: David Ahern Signed-off-by: David S. Miller