kernel/linux.git/drivers/net/tun.c, branch v6.6.143

tun: free page on build_skb failure in tun_xdp_one()

2026-06-19T11:39:10+00:00

[ Upstream commit aa8963fdce667a42fb7f0bdd2909fadcab02f9a8 ] When build_skb() fails in tun_xdp_one(), the function sets ret to -ENOMEM and jumps to the out label, which returns without freeing the page that vhost_net_build_xdp() allocated for the frame. As with the short-frame rejection path, tun_sendmsg() discards the per-buffer error and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page. Each build_skb() failure in a batch leaks one page-frag chunk. Free the page before taking the error path, matching the put_page() the other error exits of tun_xdp_one() already perform. Fixes: 043d222f93ab ("tuntap: accept an array of XDP buffs through sendmsg()") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Dongli Zhang Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260521163312.1479805-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tun: free page on short-frame rejection in tun_xdp_one()

2026-06-19T11:39:10+00:00

[ Upstream commit f4feb1e20058e407cb00f45aff47f5b7e19a6bbf ] tun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without freeing the page that vhost_net_build_xdp() allocated for it. tun_sendmsg() discards that -EINVAL and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page; each short frame in a batch leaks one page-frag chunk. A local process that can open /dev/net/tun and /dev/vhost-net can hit this path: it attaches a tun/tap device as the vhost-net backend and feeds TX descriptors whose length minus the virtio-net header is below ETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a tight submission loop exhausts host memory and triggers an OOM panic. Free the page before returning -EINVAL, matching the XDP-program error path in the same function. Fixes: 049584807f1d ("tun: add missing verification for short frame") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Dongli Zhang Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260520160020.375349-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ptr_ring: do not block hard interrupts in ptr_ring_resize_multiple()

2026-02-06T15:48:29+00:00

[ Upstream commit a126061c80d5efb4baef4bcf346094139cd81df6 ] Jakub added a lockdep_assert_no_hardirq() check in __page_pool_put_page() to increase test coverage. syzbot found a splat caused by hard irq blocking in ptr_ring_resize_multiple() [1] As current users of ptr_ring_resize_multiple() do not require hard irqs being masked, replace it to only block BH. Rename helpers to better reflect they are safe against BH only. - ptr_ring_resize_multiple() to ptr_ring_resize_multiple_bh() - skb_array_resize_multiple() to skb_array_resize_multiple_bh() [1] WARNING: CPU: 1 PID: 9150 at net/core/page_pool.c:709 __page_pool_put_page net/core/page_pool.c:709 [inline] WARNING: CPU: 1 PID: 9150 at net/core/page_pool.c:709 page_pool_put_unrefed_netmem+0x157/0xa40 net/core/page_pool.c:780 Modules linked in: CPU: 1 UID: 0 PID: 9150 Comm: syz.1.1052 Not tainted 6.11.0-rc3-syzkaller-00202-gf8669d7b5f5d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 RIP: 0010:__page_pool_put_page net/core/page_pool.c:709 [inline] RIP: 0010:page_pool_put_unrefed_netmem+0x157/0xa40 net/core/page_pool.c:780 Code: 74 0e e8 7c aa fb f7 eb 43 e8 75 aa fb f7 eb 3c 65 8b 1d 38 a8 6a 76 31 ff 89 de e8 a3 ae fb f7 85 db 74 0b e8 5a aa fb f7 90 <0f> 0b 90 eb 1d 65 8b 1d 15 a8 6a 76 31 ff 89 de e8 84 ae fb f7 85 RSP: 0018:ffffc9000bda6b58 EFLAGS: 00010083 RAX: ffffffff8997e523 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc9000fbd0000 RSI: 0000000000001842 RDI: 0000000000001843 RBP: 0000000000000000 R08: ffffffff8997df2c R09: 1ffffd40003a000d R10: dffffc0000000000 R11: fffff940003a000e R12: ffffea0001d00040 R13: ffff88802e8a4000 R14: dffffc0000000000 R15: 00000000ffffffff FS: 00007fb7aaf716c0(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa15a0d4b72 CR3: 00000000561b0000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tun_ptr_free drivers/net/tun.c:617 [inline] __ptr_ring_swap_queue include/linux/ptr_ring.h:571 [inline] ptr_ring_resize_multiple_noprof include/linux/ptr_ring.h:643 [inline] tun_queue_resize drivers/net/tun.c:3694 [inline] tun_device_event+0xaaf/0x1080 drivers/net/tun.c:3714 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2032 [inline] call_netdevice_notifiers net/core/dev.c:2046 [inline] dev_change_tx_queue_len+0x158/0x2a0 net/core/dev.c:9024 do_setlink+0xff6/0x41f0 net/core/rtnetlink.c:2923 rtnl_setlink+0x40d/0x5a0 net/core/rtnetlink.c:3201 rtnetlink_rcv_msg+0x73f/0xcf0 net/core/rtnetlink.c:6647 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550 Fixes: ff4e538c8c3e ("page_pool: add a lockdep check for recycling in hardirq") Reported-by: syzbot+f56a5c5eac2b28439810@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/671e10df.050a0220.2b8c0f.01cf.GAE@google.com/T/ Signed-off-by: Eric Dumazet Acked-by: Michael S. Tsirkin Acked-by: Jason Wang Link: https://patch.msgid.link/20241217135121.326370-1-edumazet@google.com Signed-off-by: Jakub Kicinski [ 2c321f3f70bc ("mm: change inlined allocation helpers to account at the call site") is not ported to Linux-6.6.y. So remove the suffix "_noprof". ] Signed-off-by: Alva Lan Signed-off-by: Greg Kroah-Hartman

tun: revert fix group permission check

2025-02-17T08:40:14+00:00

[ Upstream commit a70c7b3cbc0688016810bb2e0b9b8a0d6a530045 ] This reverts commit 3ca459eaba1bf96a8c7878de84fa8872259a01e3. The blamed commit caused a regression when neither tun->owner nor tun->group is set. This is intended to be allowed, but now requires CAP_NET_ADMIN. Discussion in the referenced thread pointed out that the original issue that prompted this patch can be resolved in userspace. The relaxed access control may also make a device accessible when it previously wasn't, while existing users may depend on it to not be. This is a clean pure git revert, except for fixing the indentation on the gid_valid line that checkpatch correctly flagged. Fixes: 3ca459eaba1b ("tun: fix group permission check") Link: https://lore.kernel.org/netdev/CAFqZXNtkCBT4f+PwyVRmQGoT3p1eVa01fCG_aNtpt6dakXncUg@mail.gmail.com/ Signed-off-by: Willem de Bruijn Cc: Ondrej Mosnacek Cc: Stas Sergeev Link: https://patch.msgid.link/20250204161015.739430-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tun: fix group permission check

2025-02-17T08:40:06+00:00

[ Upstream commit 3ca459eaba1bf96a8c7878de84fa8872259a01e3 ] Currently tun checks the group permission even if the user have matched. Besides going against the usual permission semantic, this has a very interesting implication: if the tun group is not among the supplementary groups of the tun user, then effectively no one can access the tun device. CAP_SYS_ADMIN still can, but its the same as not setting the tun ownership. This patch relaxes the group checking so that either the user match or the group match is enough. This avoids the situation when no one can access the device even though the ownership is properly set. Also I simplified the logic by removing the redundant inversions: tun_not_capable() --> !tun_capable() Signed-off-by: Stas Sergeev Reviewed-by: Willem de Bruijn Acked-by: Jason Wang Link: https://patch.msgid.link/20241205073614.294773-1-stsp2@yandex.ru Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: tun: fix tun_napi_alloc_frags()

2024-12-27T12:58:50+00:00

commit 429fde2d81bcef0ebab002215358955704586457 upstream. syzbot reported the following crash [1] Issue came with the blamed commit. Instead of going through all the iov components, we keep using the first one and end up with a malformed skb. [1] kernel BUG at net/core/skbuff.c:2849 ! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 UID: 0 PID: 6230 Comm: syz-executor132 Not tainted 6.13.0-rc1-syzkaller-00407-g96b6fcc0ee41 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 RIP: 0010:__pskb_pull_tail+0x1568/0x1570 net/core/skbuff.c:2848 Code: 38 c1 0f 8c 32 f1 ff ff 4c 89 f7 e8 92 96 74 f8 e9 25 f1 ff ff e8 e8 ae 09 f8 48 8b 5c 24 08 e9 eb fb ff ff e8 d9 ae 09 f8 90 <0f> 0b 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90004cbef30 EFLAGS: 00010293 RAX: ffffffff8995c347 RBX: 00000000fffffff2 RCX: ffff88802cf45a00 RDX: 0000000000000000 RSI: 00000000fffffff2 RDI: 0000000000000000 RBP: ffff88807df0c06a R08: ffffffff8995b084 R09: 1ffff1100fbe185c R10: dffffc0000000000 R11: ffffed100fbe185d R12: ffff888076e85d50 R13: ffff888076e85c80 R14: ffff888076e85cf4 R15: ffff888076e85c80 FS: 00007f0dca6ea6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0dca6ead58 CR3: 00000000119da000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_cow_data+0x2da/0xcb0 net/core/skbuff.c:5284 tipc_aead_decrypt net/tipc/crypto.c:894 [inline] tipc_crypto_rcv+0x402/0x24e0 net/tipc/crypto.c:1844 tipc_rcv+0x57e/0x12a0 net/tipc/node.c:2109 tipc_l2_rcv_msg+0x2bd/0x450 net/tipc/bearer.c:668 __netif_receive_skb_list_ptype net/core/dev.c:5720 [inline] __netif_receive_skb_list_core+0x8b7/0x980 net/core/dev.c:5762 __netif_receive_skb_list net/core/dev.c:5814 [inline] netif_receive_skb_list_internal+0xa51/0xe30 net/core/dev.c:5905 gro_normal_list include/net/gro.h:515 [inline] napi_complete_done+0x2b5/0x870 net/core/dev.c:6256 napi_complete include/linux/netdevice.h:567 [inline] tun_get_user+0x2ea0/0x4890 drivers/net/tun.c:1982 tun_chr_write_iter+0x10d/0x1f0 drivers/net/tun.c:2057 do_iter_readv_writev+0x600/0x880 vfs_writev+0x376/0xba0 fs/read_write.c:1050 do_writev+0x1b6/0x360 fs/read_write.c:1096 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: de4f5fed3f23 ("iov_iter: add iter_iovec() helper") Reported-by: syzbot+4f66250f6663c0c1d67e@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/675b61aa.050a0220.599f4.00bb.GAE@google.com/T/#u Cc: stable@vger.kernel.org Signed-off-by: Eric Dumazet Reviewed-by: Joe Damato Reviewed-by: Jens Axboe Acked-by: Willem de Bruijn Acked-by: Michael S. Tsirkin Link: https://patch.msgid.link/20241212222247.724674-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

tun: add missing verification for short frame

2024-07-27T09:34:10+00:00

commit 049584807f1d797fc3078b68035450a9769eb5c3 upstream. The cited commit missed to check against the validity of the frame length in the tun_xdp_one() path, which could cause a corrupted skb to be sent downstack. Even before the skb is transmitted, the tun_xdp_one-->eth_type_trans() may access the Ethernet header although it can be less than ETH_HLEN. Once transmitted, this could either cause out-of-bound access beyond the actual length, or confuse the underlayer with incorrect or inconsistent header length in the skb metadata. In the alternative path, tun_get_user() already prohibits short frame which has the length less than Ethernet header size from being transmitted for IFF_TAP. This is to drop any frame shorter than the Ethernet header size just like how tun_get_user() does. CVE: CVE-2024-41091 Inspired-by: https://lore.kernel.org/netdev/1717026141-25716-1-git-send-email-si-wei.liu@oracle.com/ Fixes: 043d222f93ab ("tuntap: accept an array of XDP buffs through sendmsg()") Cc: stable@vger.kernel.org Signed-off-by: Dongli Zhang Reviewed-by: Si-Wei Liu Reviewed-by: Willem de Bruijn Reviewed-by: Paolo Abeni Reviewed-by: Jason Wang Link: https://patch.msgid.link/20240724170452.16837-3-dongli.zhang@oracle.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

tun: limit printing rate when illegal packet received by tun dev

2024-04-27T15:11:33+00:00

[ Upstream commit f8bbc07ac535593139c875ffa19af924b1084540 ] vhost_worker will call tun call backs to receive packets. If too many illegal packets arrives, tun_do_read will keep dumping packet contents. When console is enabled, it will costs much more cpu time to dump packet and soft lockup will be detected. net_ratelimit mechanism can be used to limit the dumping rate. PID: 33036 TASK: ffff949da6f20000 CPU: 23 COMMAND: "vhost-32980" #0 [fffffe00003fce50] crash_nmi_callback at ffffffff89249253 #1 [fffffe00003fce58] nmi_handle at ffffffff89225fa3 #2 [fffffe00003fceb0] default_do_nmi at ffffffff8922642e #3 [fffffe00003fced0] do_nmi at ffffffff8922660d #4 [fffffe00003fcef0] end_repeat_nmi at ffffffff89c01663 [exception RIP: io_serial_in+20] RIP: ffffffff89792594 RSP: ffffa655314979e8 RFLAGS: 00000002 RAX: ffffffff89792500 RBX: ffffffff8af428a0 RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000005 RDI: ffffffff8af428a0 RBP: 0000000000002710 R8: 0000000000000004 R9: 000000000000000f R10: 0000000000000000 R11: ffffffff8acbf64f R12: 0000000000000020 R13: ffffffff8acbf698 R14: 0000000000000058 R15: 0000000000000000 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #5 [ffffa655314979e8] io_serial_in at ffffffff89792594 #6 [ffffa655314979e8] wait_for_xmitr at ffffffff89793470 #7 [ffffa65531497a08] serial8250_console_putchar at ffffffff897934f6 #8 [ffffa65531497a20] uart_console_write at ffffffff8978b605 #9 [ffffa65531497a48] serial8250_console_write at ffffffff89796558 #10 [ffffa65531497ac8] console_unlock at ffffffff89316124 #11 [ffffa65531497b10] vprintk_emit at ffffffff89317c07 #12 [ffffa65531497b68] printk at ffffffff89318306 #13 [ffffa65531497bc8] print_hex_dump at ffffffff89650765 #14 [ffffa65531497ca8] tun_do_read at ffffffffc0b06c27 [tun] #15 [ffffa65531497d38] tun_recvmsg at ffffffffc0b06e34 [tun] #16 [ffffa65531497d68] handle_rx at ffffffffc0c5d682 [vhost_net] #17 [ffffa65531497ed0] vhost_worker at ffffffffc0c644dc [vhost] #18 [ffffa65531497f10] kthread at ffffffff892d2e72 #19 [ffffa65531497f50] ret_from_fork at ffffffff89c0022f Fixes: ef3db4a59542 ("tun: avoid BUG, dump packet on GSO errors") Signed-off-by: Lei Chen Reviewed-by: Willem de Bruijn Acked-by: Jason Wang Reviewed-by: Eric Dumazet Acked-by: Michael S. Tsirkin Link: https://lore.kernel.org/r/20240415020247.2207781-1-lei.chen@smartx.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tun: Fix xdp_rxq_info's queue_index when detaching

2024-03-06T14:48:34+00:00

[ Upstream commit 2a770cdc4382b457ca3d43d03f0f0064f905a0d0 ] When a queue(tfile) is detached, we only update tfile's queue_index, but do not update xdp_rxq_info's queue_index. This patch fixes it. Fixes: 8bf5c4ee1889 ("tun: setup xdp_rxq_info") Signed-off-by: Yunjian Wang Link: https://lore.kernel.org/r/1708398727-46308-1-git-send-email-wangyunjian@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tun: add missing rx stats accounting in tun_xdp_act

2024-02-01T00:19:01+00:00

[ Upstream commit f1084c427f55d573fcd5688d9ba7b31b78019716 ] The TUN can be used as vhost-net backend, and it is necessary to count the packets transmitted from TUN to vhost-net/virtio-net. However, there are some places in the receive path that were not taken into account when using XDP. It would be beneficial to also include new accounting for successfully received bytes using dev_sw_netstats_rx_add. Fixes: 761876c857cb ("tap: XDP support") Signed-off-by: Yunjian Wang Reviewed-by: Willem de Bruijn Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin