kernel/linux.git/drivers/net/tap.c, branch v6.18.36

tap: free page on error paths in tap_get_user_xdp()

2026-06-19T11:43:57+00:00

[ Upstream commit 3bcf7aec6a9d16438f2cec29f5d7c8d5b8edf9b2 ] tap_get_user_xdp() rejects a frame shorter than ETH_HLEN with -EINVAL, and returns -ENOMEM when build_skb() fails. Both paths jump to the err label without freeing the page that vhost_net_build_xdp() allocated for the frame. tap_sendmsg() discards the per-buffer return value and always returns 0, so vhost_tx_batch() takes the success path and never frees the page; each rejected frame in a batch leaks one page-frag chunk. Free the page on both error paths, before the skb is built. This is the tap counterpart of the same leak in tun_xdp_one(). Fixes: 0efac27791ee ("tap: accept an array of XDP buffs through sendmsg()") Fixes: ed7f2afdd0e0 ("tap: 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/20260521163230.1478627-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski (cherry picked from commit 3bcf7aec6a9d16438f2cec29f5d7c8d5b8edf9b2) Signed-off-by: Harshit Mogalapalli Signed-off-by: Sasha Levin

tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR

2026-06-01T15:51:07+00:00

[ Upstream commit bddc09212c24934643bd44fc794748d2bbb3b6cd ] In the SIOCGIFHWADDR path, tap_ioctl() copies 16 bytes of an uninitialised on-stack struct sockaddr_storage to userspace via ifr_hwaddr, but netif_get_mac_address() only writes sa_family and dev->addr_len (6 for Ethernet) bytes, leaving sa_data[6..13] uninitialised. Those 8 trailing bytes leak kernel stack contents; SIOCGIFHWADDR on a macvtap chardev returns kernel .text and direct-map pointers, defeating KASLR. Initialise ss at declaration. Fixes: 3b23a32a6321 ("net: fix dev_ifsioc_locked() race condition") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260520075736.3415676-3-bestswngs@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: s/dev_get_mac_address/netif_get_mac_address/

2025-07-19T00:27:46+00:00

Commit cc34acd577f1 ("docs: net: document new locking reality") introduced netif_ vs dev_ function semantics: the former expects locked netdev, the latter takes care of the locking. We don't strictly follow this semantics on either side, but there are more dev_xxx handlers now that don't fit. Rename them to netif_xxx where appropriate. netif_get_mac_address is used only by tun/tap, so move it into NETDEV_INTERNAL namespace. Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250717172333.1288349-3-sdf@fomichev.me Signed-off-by: Jakub Kicinski

tun: remove unnecessary tun_xdp_hdr structure

2025-07-02T22:29:46+00:00

With f95f0f95cfb7("net, xdp: Introduce xdp_init_buff utility routine"), buffer length could be stored as frame size so there's no need to have a dedicated tun_xdp_hdr structure. We can simply store virtio net header instead. Acked-by: Willem de Bruijn Signed-off-by: Jason Wang Link: https://patch.msgid.link/20250701010352.74515-1-jasowang@redhat.com Signed-off-by: Jakub Kicinski

net: core: Convert dev_set_mac_address_user() to use struct sockaddr_storage

2025-05-27T06:25:43+00:00

Convert callers of dev_set_mac_address_user() to use struct sockaddr_storage. Add sanity checks on dev->addr_len usage. Signed-off-by: Kees Cook Acked-by: Gustavo A. R. Silva Link: https://patch.msgid.link/20250521204619.2301870-8-kees@kernel.org Signed-off-by: Paolo Abeni

Revert "net: replace dev_addr_sem with netdev instance lock"

2025-03-19T17:52:00+00:00

This reverts commit df43d8bf10316a7c3b1e47e3cc0057a54df4a5b8. Cc: Kohei Enju Reviewed-by: Kuniyuki Iwashima Fixes: df43d8bf1031 ("net: replace dev_addr_sem with netdev instance lock") Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250312190513.1252045-2-sdf@fomichev.me Tested-by: Lei Yang Signed-off-by: Paolo Abeni

net: replace dev_addr_sem with netdev instance lock

2025-03-06T20:59:45+00:00

Lockdep reports possible circular dependency in [0]. Instead of fixing the ordering, replace global dev_addr_sem with netdev instance lock. Most of the paths that set/get mac are RTNL protected. Two places where it's not, convert to explicit locking: - sysfs address_show - dev_get_mac_address via dev_ioctl 0: https://netdev-3.bots.linux.dev/vmksft-forwarding-dbg/results/993321/24-router-bridge-1d-lag-sh/stderr Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250305163732.2766420-12-sdf@fomichev.me Signed-off-by: Jakub Kicinski

tap: Use tun's vnet-related code

2025-02-11T03:07:11+00:00

tun and tap implements the same vnet-related features so reuse the code. Signed-off-by: Akihiko Odaki Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20250207-tun-v6-7-fb49cf8b103e@daynix.com Signed-off-by: Jakub Kicinski

tap: Keep hdr_len in tap_get_user()

2025-02-11T03:07:11+00:00

hdr_len is repeatedly used so keep it in a local variable. Signed-off-by: Akihiko Odaki Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20250207-tun-v6-6-fb49cf8b103e@daynix.com Signed-off-by: Jakub Kicinski

ptr_ring: do not block hard interrupts in ptr_ring_resize_multiple()

2024-12-19T01:55:30+00:00

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