kernel/linux.git/drivers/net/gtp.c, branch v6.12.101

gtp: check skb_pull_data() return in gtp1u_send_echo_resp()

2026-08-03T09:17:12+00:00

[ Upstream commit cd170f051dba9ac146fabcd1b91726487c0cb9fa ] gtp1u_send_echo_resp() ignores skb_pull_data()'s return value. Its caller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr + gtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For a 16-19 byte echo request the pull fails and returns NULL without advancing skb->data; execution continues, and the following skb_push() plus the IP header pushed by iptunnel_xmit() move skb->data below skb->head, tripping skb_under_panic(). Fix it by dropping the packet when skb_pull_data() fails. skbuff: skb_under_panic: ... kernel BUG at net/core/skbuff.c:214! Call Trace: skb_push (net/core/skbuff.c:2648) iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82) gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920) udp_queue_rcv_one_skb (net/ipv4/udp.c:2388) ... Kernel panic - not syncing: Fatal exception in interrupt Fixes: 9af41cc33471 ("gtp: Implement GTP echo response") Reported-by: AutonomousCodeSecurity@microsoft.com Signed-off-by: Xiang Mei (Microsoft) Link: https://patch.msgid.link/20260710230724.942574-1-xmei5@asu.edu Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

gtp: parse extension headers before reading inner protocol

2026-08-03T09:17:10+00:00

[ Upstream commit 96e37e2f618e931aa97af95e707dcdfb1ec41264 ] GTPv1-U packets may carry a chain of extension headers before the inner IP packet. The receive path already parses and skips these extension headers, but it currently reads the inner protocol before doing so. As a result, the first extension header byte is interpreted as the inner IP version. Packets with extension headers are then dropped before PDP lookup. Parse the extension header chain before calling gtp_inner_proto(), so the inner protocol is read from the actual inner IP header. Fixes: c75fc0b9e5be ("gtp: identify tunnel via GTP device + GTP version + TEID + family") Signed-off-by: Zhixing Chen Link: https://patch.msgid.link/20260708042244.120898-1-running910@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

gtp: disable BH before calling udp_tunnel_xmit_skb()

2026-05-14T13:29:29+00:00

[ Upstream commit 5638504a2aa9e1b9d72af9060df1a160cce2d379 ] gtp_genl_send_echo_req() runs as a generic netlink doit handler in process context with BH not disabled. It calls udp_tunnel_xmit_skb(), which eventually invokes iptunnel_xmit() — that uses __this_cpu_inc/dec on softnet_data.xmit.recursion to track the tunnel xmit recursion level. Without local_bh_disable(), the task may migrate between dev_xmit_recursion_inc() and dev_xmit_recursion_dec(), breaking the per-CPU counter pairing. The result is stale or negative recursion levels that can later produce false-positive SKB_DROP_REASON_RECURSION_LIMIT drops on either CPU. The other udp_tunnel_xmit_skb() call sites in gtp.c are unaffected: the data path runs under ndo_start_xmit and the echo response handlers run from the UDP encap rx softirq, both with BH already disabled. Fix it by disabling BH around the udp_tunnel_xmit_skb() call, mirroring commit 2cd7e6971fc2 ("sctp: disable BH before calling udp_tunnel_xmit_skb()"). Fixes: 6f1a9140ecda ("net: add xmit recursion limit to tunnel xmit functions") Cc: stable@vger.kernel.org Signed-off-by: David Carlier Link: https://patch.msgid.link/20260417055408.4667-1-devnexen@gmail.com Signed-off-by: Jakub Kicinski [ Context ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

gtp: Suppress list corruption splat in gtp_net_exit_batch_rtnl().

2025-02-27T12:30:18+00:00

[ Upstream commit 4ccacf86491d33d2486b62d4d44864d7101b299d ] Brad Spengler reported the list_del() corruption splat in gtp_net_exit_batch_rtnl(). [0] Commit eb28fd76c0a0 ("gtp: Destroy device along with udp socket's netns dismantle.") added the for_each_netdev() loop in gtp_net_exit_batch_rtnl() to destroy devices in each netns as done in geneve and ip tunnels. However, this could trigger ->dellink() twice for the same device during ->exit_batch_rtnl(). Say we have two netns A & B and gtp device B that resides in netns B but whose UDP socket is in netns A. 1. cleanup_net() processes netns A and then B. 2. gtp_net_exit_batch_rtnl() finds the device B while iterating netns A's gn->gtp_dev_list and calls ->dellink(). [ device B is not yet unlinked from netns B as unregister_netdevice_many() has not been called. ] 3. gtp_net_exit_batch_rtnl() finds the device B while iterating netns B's for_each_netdev() and calls ->dellink(). gtp_dellink() cleans up the device's hash table, unlinks the dev from gn->gtp_dev_list, and calls unregister_netdevice_queue(). Basically, calling gtp_dellink() multiple times is fine unless CONFIG_DEBUG_LIST is enabled. Let's remove for_each_netdev() in gtp_net_exit_batch_rtnl() and delegate the destruction to default_device_exit_batch() as done in bareudp. [0]: list_del corruption, ffff8880aaa62c00->next (autoslab_size_M_dev_P_net_core_dev_11127_8_1328_8_S_4096_A_64_n_139+0xc00/0x1000 [slab object]) is LIST_POISON1 (ffffffffffffff02) (prev is 0xffffffffffffff04) kernel BUG at lib/list_debug.c:58! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 UID: 0 PID: 1804 Comm: kworker/u8:7 Tainted: G T 6.12.13-grsec-full-20250211091339 #1 Tainted: [T]=RANDSTRUCT Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: netns cleanup_net RIP: 0010:[] __list_del_entry_valid_or_report+0x141/0x200 lib/list_debug.c:58 Code: c2 76 91 31 c0 e8 9f b1 f7 fc 0f 0b 4d 89 f0 48 c7 c1 02 ff ff ff 48 89 ea 48 89 ee 48 c7 c7 e0 c2 76 91 31 c0 e8 7f b1 f7 fc <0f> 0b 4d 89 e8 48 c7 c1 04 ff ff ff 48 89 ea 48 89 ee 48 c7 c7 60 RSP: 0018:fffffe8040b4fbd0 EFLAGS: 00010283 RAX: 00000000000000cc RBX: dffffc0000000000 RCX: ffffffff818c4054 RDX: ffffffff84947381 RSI: ffffffff818d1512 RDI: 0000000000000000 RBP: ffff8880aaa62c00 R08: 0000000000000001 R09: fffffbd008169f32 R10: fffffe8040b4f997 R11: 0000000000000001 R12: a1988d84f24943e4 R13: ffffffffffffff02 R14: ffffffffffffff04 R15: ffff8880aaa62c08 RBX: kasan shadow of 0x0 RCX: __wake_up_klogd.part.0+0x74/0xe0 kernel/printk/printk.c:4554 RDX: __list_del_entry_valid_or_report+0x141/0x200 lib/list_debug.c:58 RSI: vprintk+0x72/0x100 kernel/printk/printk_safe.c:71 RBP: autoslab_size_M_dev_P_net_core_dev_11127_8_1328_8_S_4096_A_64_n_139+0xc00/0x1000 [slab object] RSP: process kstack fffffe8040b4fbd0+0x7bd0/0x8000 [kworker/u8:7+netns 1804 ] R09: kasan shadow of process kstack fffffe8040b4f990+0x7990/0x8000 [kworker/u8:7+netns 1804 ] R10: process kstack fffffe8040b4f997+0x7997/0x8000 [kworker/u8:7+netns 1804 ] R15: autoslab_size_M_dev_P_net_core_dev_11127_8_1328_8_S_4096_A_64_n_139+0xc08/0x1000 [slab object] FS: 0000000000000000(0000) GS:ffff888116000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000748f5372c000 CR3: 0000000015408000 CR4: 00000000003406f0 shadow CR4: 00000000003406f0 Stack: 0000000000000000 ffffffff8a0c35e7 ffffffff8a0c3603 ffff8880aaa62c00 ffff8880aaa62c00 0000000000000004 ffff88811145311c 0000000000000005 0000000000000001 ffff8880aaa62000 fffffe8040b4fd40 ffffffff8a0c360d Call Trace: [] __list_del_entry_valid include/linux/list.h:131 [inline] fffffe8040b4fc28 [] __list_del_entry include/linux/list.h:248 [inline] fffffe8040b4fc28 [] list_del include/linux/list.h:262 [inline] fffffe8040b4fc28 [] gtp_dellink+0x16d/0x360 drivers/net/gtp.c:1557 fffffe8040b4fc28 [] gtp_net_exit_batch_rtnl+0x124/0x2c0 drivers/net/gtp.c:2495 fffffe8040b4fc88 [] cleanup_net+0x5a4/0xbe0 net/core/net_namespace.c:635 fffffe8040b4fcd0 [] process_one_work+0xbd7/0x2160 kernel/workqueue.c:3326 fffffe8040b4fd88 [] process_scheduled_works kernel/workqueue.c:3407 [inline] fffffe8040b4fec0 [] worker_thread+0x6b5/0xfa0 kernel/workqueue.c:3488 fffffe8040b4fec0 [] kthread+0x360/0x4c0 kernel/kthread.c:397 fffffe8040b4ff78 [] ret_from_fork+0x74/0xe0 arch/x86/kernel/process.c:172 fffffe8040b4ffb8 [] ret_from_fork_asm+0x29/0xc0 arch/x86/entry/entry_64.S:399 fffffe8040b4ffe8 Modules linked in: Fixes: eb28fd76c0a0 ("gtp: Destroy device along with udp socket's netns dismantle.") Reported-by: Brad Spengler Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250217203705.40342-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

gtp: Destroy device along with udp socket's netns dismantle.

2025-01-23T16:22:50+00:00

[ Upstream commit eb28fd76c0a08a47b470677c6cef9dd1c60e92d1 ] gtp_newlink() links the device to a list in dev_net(dev) instead of src_net, where a udp tunnel socket is created. Even when src_net is removed, the device stays alive on dev_net(dev). Then, removing src_net triggers the splat below. [0] In this example, gtp0 is created in ns2, and the udp socket is created in ns1. ip netns add ns1 ip netns add ns2 ip -n ns1 link add netns ns2 name gtp0 type gtp role sgsn ip netns del ns1 Let's link the device to the socket's netns instead. Now, gtp_net_exit_batch_rtnl() needs another netdev iteration to remove all gtp devices in the netns. [0]: ref_tracker: net notrefcnt@000000003d6e7d05 has 1/2 users at sk_alloc (./include/net/net_namespace.h:345 net/core/sock.c:2236) inet_create (net/ipv4/af_inet.c:326 net/ipv4/af_inet.c:252) __sock_create (net/socket.c:1558) udp_sock_create4 (net/ipv4/udp_tunnel_core.c:18) gtp_create_sock (./include/net/udp_tunnel.h:59 drivers/net/gtp.c:1423) gtp_create_sockets (drivers/net/gtp.c:1447) gtp_newlink (drivers/net/gtp.c:1507) rtnl_newlink (net/core/rtnetlink.c:3786 net/core/rtnetlink.c:3897 net/core/rtnetlink.c:4012) rtnetlink_rcv_msg (net/core/rtnetlink.c:6922) netlink_rcv_skb (net/netlink/af_netlink.c:2542) netlink_unicast (net/netlink/af_netlink.c:1321 net/netlink/af_netlink.c:1347) netlink_sendmsg (net/netlink/af_netlink.c:1891) ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2583) ___sys_sendmsg (net/socket.c:2639) __sys_sendmsg (net/socket.c:2669) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) WARNING: CPU: 1 PID: 60 at lib/ref_tracker.c:179 ref_tracker_dir_exit (lib/ref_tracker.c:179) Modules linked in: CPU: 1 UID: 0 PID: 60 Comm: kworker/u16:2 Not tainted 6.13.0-rc5-00147-g4c1224501e9d #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: netns cleanup_net RIP: 0010:ref_tracker_dir_exit (lib/ref_tracker.c:179) Code: 00 00 00 fc ff df 4d 8b 26 49 bd 00 01 00 00 00 00 ad de 4c 39 f5 0f 85 df 00 00 00 48 8b 74 24 08 48 89 df e8 a5 cc 12 02 90 <0f> 0b 90 48 8d 6b 44 be 04 00 00 00 48 89 ef e8 80 de 67 ff 48 89 RSP: 0018:ff11000009a07b60 EFLAGS: 00010286 RAX: 0000000000002bd3 RBX: ff1100000f4e1aa0 RCX: 1ffffffff0e40ac6 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8423ee3c RBP: ff1100000f4e1af0 R08: 0000000000000001 R09: fffffbfff0e395ae R10: 0000000000000001 R11: 0000000000036001 R12: ff1100000f4e1af0 R13: dead000000000100 R14: ff1100000f4e1af0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ff1100006ce80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9b2464bd98 CR3: 0000000005286005 CR4: 0000000000771ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? __warn (kernel/panic.c:748) ? ref_tracker_dir_exit (lib/ref_tracker.c:179) ? report_bug (lib/bug.c:201 lib/bug.c:219) ? handle_bug (arch/x86/kernel/traps.c:285) ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1)) ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621) ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:97 ./arch/x86/include/asm/irqflags.h:155 ./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) ? ref_tracker_dir_exit (lib/ref_tracker.c:179) ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:158) ? kfree (mm/slub.c:4613 mm/slub.c:4761) net_free (net/core/net_namespace.c:476 net/core/net_namespace.c:467) cleanup_net (net/core/net_namespace.c:664 (discriminator 3)) process_one_work (kernel/workqueue.c:3229) worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391) kthread (kernel/kthread.c:389) ret_from_fork (arch/x86/kernel/process.c:147) ret_from_fork_asm (arch/x86/entry/entry_64.S:257) Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)") Reported-by: Xiao Liang Closes: https://lore.kernel.org/netdev/20250104125732.17335-1-shaw.leon@gmail.com/ Signed-off-by: Kuniyuki Iwashima Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

gtp: Use for_each_netdev_rcu() in gtp_genl_dump_pdp().

2025-01-23T16:22:50+00:00

[ Upstream commit 46841c7053e6d25fb33e0534ef023833bf03e382 ] gtp_newlink() links the gtp device to a list in dev_net(dev). However, even after the gtp device is moved to another netns, it stays on the list but should be invisible. Let's use for_each_netdev_rcu() for netdev traversal in gtp_genl_dump_pdp(). Note that gtp_dev_list is no longer used under RCU, so list helpers are converted to the non-RCU variant. Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)") Reported-by: Xiao Liang Closes: https://lore.kernel.org/netdev/CABAhCOQdBL6h9M2C+kd+bGivRJ9Q72JUxW+-gur0nub_=PmFPA@mail.gmail.com/ Signed-off-by: Kuniyuki Iwashima Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

gtp: allow -1 to be specified as file description from userspace

2024-10-29T18:24:08+00:00

Existing user space applications maintained by the Osmocom project are breaking since a recent fix that addresses incorrect error checking. Restore operation for user space programs that specify -1 as file descriptor to skip GTPv0 or GTPv1 only sockets. Fixes: defd8b3c37b0 ("gtp: fix a potential NULL pointer dereference") Reported-by: Pau Espin Pedrol Signed-off-by: Pablo Neira Ayuso Tested-by: Oliver Smith Reviewed-by: Simon Horman Link: https://patch.msgid.link/20241022144825.66740-1-pablo@netfilter.org Signed-off-by: Jakub Kicinski

netdev_features: convert NETIF_F_LLTX to dev->lltx

2024-09-03T09:36:43+00:00

NETIF_F_LLTX can't be changed via Ethtool and is not a feature, rather an attribute, very similar to IFF_NO_QUEUE (and hot). Free one netdev_features_t bit and make it a "hot" private flag. Signed-off-by: Alexander Lobakin Signed-off-by: Paolo Abeni

gtp: fix a potential NULL pointer dereference

2024-08-27T21:19:40+00:00

When sockfd_lookup() fails, gtp_encap_enable_socket() returns a NULL pointer, but its callers only check for error pointers thus miss the NULL pointer case. Fix it by returning an error pointer with the error code carried from sockfd_lookup(). (I found this bug during code inspection.) Fixes: 1e3a3abd8b28 ("gtp: make GTP sockets in gtp_newlink optional") Cc: Andreas Schultz Cc: Harald Welte Signed-off-by: Cong Wang Reviewed-by: Simon Horman Reviewed-by: Pablo Neira Ayuso Link: https://patch.msgid.link/20240825191638.146748-1-xiyou.wangcong@gmail.com Signed-off-by: Jakub Kicinski

gtp: pull network headers in gtp_dev_xmit()

2024-08-10T04:56:44+00:00

syzbot/KMSAN reported use of uninit-value in get_dev_xmit() [1] We must make sure the IPv4 or Ipv6 header is pulled in skb->head before accessing fields in them. Use pskb_inet_may_pull() to fix this issue. [1] BUG: KMSAN: uninit-value in ipv6_pdp_find drivers/net/gtp.c:220 [inline] BUG: KMSAN: uninit-value in gtp_build_skb_ip6 drivers/net/gtp.c:1229 [inline] BUG: KMSAN: uninit-value in gtp_dev_xmit+0x1424/0x2540 drivers/net/gtp.c:1281 ipv6_pdp_find drivers/net/gtp.c:220 [inline] gtp_build_skb_ip6 drivers/net/gtp.c:1229 [inline] gtp_dev_xmit+0x1424/0x2540 drivers/net/gtp.c:1281 __netdev_start_xmit include/linux/netdevice.h:4913 [inline] netdev_start_xmit include/linux/netdevice.h:4922 [inline] xmit_one net/core/dev.c:3580 [inline] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3596 __dev_queue_xmit+0x358c/0x5610 net/core/dev.c:4423 dev_queue_xmit include/linux/netdevice.h:3105 [inline] packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3145 [inline] packet_sendmsg+0x90e3/0xa3a0 net/packet/af_packet.c:3177 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 __sys_sendto+0x685/0x830 net/socket.c:2204 __do_sys_sendto net/socket.c:2216 [inline] __se_sys_sendto net/socket.c:2212 [inline] __x64_sys_sendto+0x125/0x1d0 net/socket.c:2212 x64_sys_call+0x3799/0x3c10 arch/x86/include/generated/asm/syscalls_64.h:45 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:3994 [inline] slab_alloc_node mm/slub.c:4037 [inline] kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4080 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:583 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:674 alloc_skb include/linux/skbuff.h:1320 [inline] alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6526 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2815 packet_alloc_skb net/packet/af_packet.c:2994 [inline] packet_snd net/packet/af_packet.c:3088 [inline] packet_sendmsg+0x749c/0xa3a0 net/packet/af_packet.c:3177 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 __sys_sendto+0x685/0x830 net/socket.c:2204 __do_sys_sendto net/socket.c:2216 [inline] __se_sys_sendto net/socket.c:2212 [inline] __x64_sys_sendto+0x125/0x1d0 net/socket.c:2212 x64_sys_call+0x3799/0x3c10 arch/x86/include/generated/asm/syscalls_64.h:45 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 7115 Comm: syz.1.515 Not tainted 6.11.0-rc1-syzkaller-00043-g94ede2a3e913 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Fixes: 999cb275c807 ("gtp: add IPv6 support") Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)") Signed-off-by: Eric Dumazet Cc: Harald Welte Reviewed-by: Pablo Neira Ayuso Link: https://patch.msgid.link/20240808132455.3413916-1-edumazet@google.com Signed-off-by: Jakub Kicinski