kernel/linux.git/net/ipv4/ip_gre.c, branch v6.6.131

ipv4: ip_gre: make ipgre_header() robust

2026-01-30T09:27:24+00:00

[ Upstream commit e67c577d89894811ce4dcd1a9ed29d8b63476667 ] Analog to commit db5b4e39c4e6 ("ip6_gre: make ip6gre_header() robust") Over the years, syzbot found many ways to crash the kernel in ipgre_header() [1]. This involves team or bonding drivers ability to dynamically change their dev->needed_headroom and/or dev->hard_header_len In this particular crash mld_newpack() allocated an skb with a too small reserve/headroom, and by the time mld_sendpack() was called, syzbot managed to attach an ipgre device. [1] skbuff: skb_under_panic: text:ffffffff89ea3cb7 len:2030915468 put:2030915372 head:ffff888058b43000 data:ffff887fdfa6e194 tail:0x120 end:0x6c0 dev:team0 kernel BUG at net/core/skbuff.c:213 ! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 1322 Comm: kworker/1:9 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: mld mld_ifc_work RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213 Call Trace: skb_under_panic net/core/skbuff.c:223 [inline] skb_push+0xc3/0xe0 net/core/skbuff.c:2641 ipgre_header+0x67/0x290 net/ipv4/ip_gre.c:897 dev_hard_header include/linux/netdevice.h:3436 [inline] neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318 mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Reported-by: syzbot+7c134e1c3aa3283790b9@syzkaller.appspotmail.com Closes: https://www.spinics.net/lists/netdev/msg1147302.html Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260108190214.1667040-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv4: ip_gre: Fix set but not used warning in ipgre_err() if IPv4-only

2025-06-04T12:42:12+00:00

[ Upstream commit 50f37fc2a39c4a8cc4813629b4cf239b71c6097d ] if CONFIG_NET_IPGRE is enabled, but CONFIG_IPV6 is disabled: net/ipv4/ip_gre.c: In function ‘ipgre_err’: net/ipv4/ip_gre.c:144:22: error: variable ‘data_len’ set but not used [-Werror=unused-but-set-variable] 144 | unsigned int data_len = 0; | ^~~~~~~~ Fix this by moving all data_len processing inside the IPV6-only section that uses its result. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202501121007.2GofXmh5-lkp@intel.com/ Signed-off-by: Geert Uytterhoeven Reviewed-by: Simon Horman Link: https://patch.msgid.link/d09113cfe2bfaca02f3dddf832fb5f48dd20958b.1738704881.git.geert@linux-m68k.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv4: ip_gre: Fix drops of small packets in ipgre_xmit

2024-10-10T09:57:17+00:00

[ Upstream commit c4a14f6d9d17ad1e41a36182dd3b8a5fd91efbd7 ] Regression Description: Depending on the options specified for the GRE tunnel device, small packets may be dropped. This occurs because the pskb_network_may_pull function fails due to the packet's insufficient length. For example, if only the okey option is specified for the tunnel device, original (before encapsulation) packets smaller than 28 bytes (including the IPv4 header) will be dropped. This happens because the required length is calculated relative to the network header, not the skb->head. Here is how the required length is computed and checked: * The pull_len variable is set to 28 bytes, consisting of: * IPv4 header: 20 bytes * GRE header with Key field: 8 bytes * The pskb_network_may_pull function adds the network offset, shifting the checkable space further to the beginning of the network header and extending it to the beginning of the packet. As a result, the end of the checkable space occurs beyond the actual end of the packet. Instead of ensuring that 28 bytes are present in skb->head, the function is requesting these 28 bytes starting from the network header. For small packets, this requested length exceeds the actual packet size, causing the check to fail and the packets to be dropped. This issue affects both locally originated and forwarded packets in DMVPN-like setups. How to reproduce (for local originated packets): ip link add dev gre1 type gre ikey 1.9.8.4 okey 1.9.8.4 \ local remote 0.0.0.0 ip link set mtu 1400 dev gre1 ip link set up dev gre1 ip address add 192.168.13.1/24 dev gre1 ip neighbor add 192.168.13.2 lladdr dev gre1 ping -s 1374 -c 10 192.168.13.2 tcpdump -vni gre1 tcpdump -vni 'ip proto 47' ip -s -s -d link show dev gre1 Solution: Use the pskb_may_pull function instead the pskb_network_may_pull. Fixes: 80d875cfc9d3 ("ipv4: ip_gre: Avoid skb_pull() failure in ipgre_xmit()") Signed-off-by: Anton Danilov Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20240924235158.106062-1-littlesmilingcloud@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

erspan: make sure erspan_base_hdr is present in skb->head

2024-04-10T14:35:53+00:00

commit 17af420545a750f763025149fa7b833a4fc8b8f0 upstream. syzbot reported a problem in ip6erspan_rcv() [1] Issue is that ip6erspan_rcv() (and erspan_rcv()) no longer make sure erspan_base_hdr is present in skb linear part (skb->head) before getting @ver field from it. Add the missing pskb_may_pull() calls. v2: Reload iph pointer in erspan_rcv() after pskb_may_pull() because skb->head might have changed. [1] BUG: KMSAN: uninit-value in pskb_may_pull_reason include/linux/skbuff.h:2742 [inline] BUG: KMSAN: uninit-value in pskb_may_pull include/linux/skbuff.h:2756 [inline] BUG: KMSAN: uninit-value in ip6erspan_rcv net/ipv6/ip6_gre.c:541 [inline] BUG: KMSAN: uninit-value in gre_rcv+0x11f8/0x1930 net/ipv6/ip6_gre.c:610 pskb_may_pull_reason include/linux/skbuff.h:2742 [inline] pskb_may_pull include/linux/skbuff.h:2756 [inline] ip6erspan_rcv net/ipv6/ip6_gre.c:541 [inline] gre_rcv+0x11f8/0x1930 net/ipv6/ip6_gre.c:610 ip6_protocol_deliver_rcu+0x1d4c/0x2ca0 net/ipv6/ip6_input.c:438 ip6_input_finish net/ipv6/ip6_input.c:483 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] ip6_input+0x15d/0x430 net/ipv6/ip6_input.c:492 ip6_mc_input+0xa7e/0xc80 net/ipv6/ip6_input.c:586 dst_input include/net/dst.h:460 [inline] ip6_rcv_finish+0x955/0x970 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:314 [inline] ipv6_rcv+0xde/0x390 net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core net/core/dev.c:5538 [inline] __netif_receive_skb+0x1da/0xa00 net/core/dev.c:5652 netif_receive_skb_internal net/core/dev.c:5738 [inline] netif_receive_skb+0x58/0x660 net/core/dev.c:5798 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1549 tun_get_user+0x5566/0x69e0 drivers/net/tun.c:2002 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048 call_write_iter include/linux/fs.h:2108 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0xb63/0x1520 fs/read_write.c:590 ksys_write+0x20f/0x4c0 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __x64_sys_write+0x93/0xe0 fs/read_write.c:652 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 tun_alloc_skb drivers/net/tun.c:1525 [inline] tun_get_user+0x209a/0x69e0 drivers/net/tun.c:1846 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048 call_write_iter include/linux/fs.h:2108 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0xb63/0x1520 fs/read_write.c:590 ksys_write+0x20f/0x4c0 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __x64_sys_write+0x93/0xe0 fs/read_write.c:652 do_syscall_64+0xd5/0x1f0 entry_SYSCALL_64_after_hwframe+0x6d/0x75 CPU: 1 PID: 5045 Comm: syz-executor114 Not tainted 6.9.0-rc1-syzkaller-00021-g962490525cff #0 Fixes: cb73ee40b1b3 ("net: ip_gre: use erspan key field for tunnel lookup") Reported-by: syzbot+1c1cf138518bf0c53d68@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/000000000000772f2c0614b66ef7@google.com/ Signed-off-by: Eric Dumazet Cc: Lorenzo Bianconi Link: https://lore.kernel.org/r/20240328112248.1101491-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

ipv4: ip_gre: Avoid skb_pull() failure in ipgre_xmit()

2023-12-13T17:45:07+00:00

[ Upstream commit 80d875cfc9d3711a029f234ef7d680db79e8fa4b ] In ipgre_xmit(), skb_pull() may fail even if pskb_inet_may_pull() returns true. For example, applications can use PF_PACKET to create a malformed packet with no IP header. This type of packet causes a problem such as uninit-value access. This patch ensures that skb_pull() can pull the required size by checking the skb with pskb_network_may_pull() before skb_pull(). Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Signed-off-by: Shigeru Yoshida Reviewed-by: Eric Dumazet Reviewed-by: Suman Ghosh Link: https://lore.kernel.org/r/20231202161441.221135-1-syoshida@redhat.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

ipv4: ip_gre: fix return value check in erspan_xmit()

2023-07-19T11:27:09+00:00

goto free_skb if an unexpected result is returned by pskb_tirm() in erspan_xmit(). Signed-off-by: Yuanjun Gong Reviewed-by: Kuniyuki Iwashima Signed-off-by: David S. Miller

ipv4: ip_gre: fix return value check in erspan_fb_xmit()

2023-07-19T11:27:09+00:00

goto err_free_skb if an unexpected result is returned by pskb_tirm() in erspan_fb_xmit(). Signed-off-by: Yuanjun Gong Reviewed-by: Kuniyuki Iwashima Signed-off-by: David S. Miller

ip_gre: clean up some inconsistent indenting

2023-06-02T09:44:46+00:00

No functional modification involved. net/ipv4/ip_gre.c:192 ipgre_err() warn: inconsistent indenting. Reported-by: Abaci Robot Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=5375 Signed-off-by: Jiapeng Chong Signed-off-by: David S. Miller

erspan: do not use skb_mac_header() in ndo_start_xmit()

2023-03-22T04:16:26+00:00

Drivers should not assume skb_mac_header(skb) == skb->data in their ndo_start_xmit(). Use skb_network_offset() and skb_transport_offset() which better describe what is needed in erspan_fb_xmit() and ip6erspan_tunnel_xmit() syzbot reported: WARNING: CPU: 0 PID: 5083 at include/linux/skbuff.h:2873 skb_mac_header include/linux/skbuff.h:2873 [inline] WARNING: CPU: 0 PID: 5083 at include/linux/skbuff.h:2873 ip6erspan_tunnel_xmit+0x1d9c/0x2d90 net/ipv6/ip6_gre.c:962 Modules linked in: CPU: 0 PID: 5083 Comm: syz-executor406 Not tainted 6.3.0-rc2-syzkaller-00866-gd4671cb96fa3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 RIP: 0010:skb_mac_header include/linux/skbuff.h:2873 [inline] RIP: 0010:ip6erspan_tunnel_xmit+0x1d9c/0x2d90 net/ipv6/ip6_gre.c:962 Code: 04 02 41 01 de 84 c0 74 08 3c 03 0f 8e 1c 0a 00 00 45 89 b4 24 c8 00 00 00 c6 85 77 fe ff ff 01 e9 33 e7 ff ff e8 b4 27 a1 f8 <0f> 0b e9 b6 e7 ff ff e8 a8 27 a1 f8 49 8d bf f0 0c 00 00 48 b8 00 RSP: 0018:ffffc90003b2f830 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 000000000000ffff RCX: 0000000000000000 RDX: ffff888021273a80 RSI: ffffffff88e1bd4c RDI: 0000000000000003 RBP: ffffc90003b2f9d8 R08: 0000000000000003 R09: 000000000000ffff R10: 000000000000ffff R11: 0000000000000000 R12: ffff88802b28da00 R13: 00000000000000d0 R14: ffff88807e25b6d0 R15: ffff888023408000 FS: 0000555556a61300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055e5b11eb6e8 CR3: 0000000027c1b000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __netdev_start_xmit include/linux/netdevice.h:4900 [inline] netdev_start_xmit include/linux/netdevice.h:4914 [inline] __dev_direct_xmit+0x504/0x730 net/core/dev.c:4300 dev_direct_xmit include/linux/netdevice.h:3088 [inline] packet_xmit+0x20a/0x390 net/packet/af_packet.c:285 packet_snd net/packet/af_packet.c:3075 [inline] packet_sendmsg+0x31a0/0x5150 net/packet/af_packet.c:3107 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 __sys_sendto+0x23a/0x340 net/socket.c:2142 __do_sys_sendto net/socket.c:2154 [inline] __se_sys_sendto net/socket.c:2150 [inline] __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2150 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f123aaa1039 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc15d12058 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f123aaa1039 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000020000040 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f123aa648c0 R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000 Fixes: 1baf5ebf8954 ("erspan: auto detect truncated packets.") Reported-by: syzbot Signed-off-by: Eric Dumazet Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20230320163427.8096-1-edumazet@google.com Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2022-12-09T02:19:59+00:00

No conflicts. Signed-off-by: Jakub Kicinski