Bingquan Chen 2c054e17d9 net/packet: fix TOCTOU race on mmap'd vnet_hdr in tpacket_snd() ... In tpacket_snd(), when PACKET_VNET_HDR is enabled, vnet_hdr points directly into the mmap'd TX ring buffer shared with userspace. The kernel validates the header via __packet_snd_vnet_parse() but then re-reads all fields later in virtio_net_hdr_to_skb(). A concurrent userspace thread can modify the vnet_hdr fields between validation and use, bypassing all safety checks. The non-TPACKET path (packet_snd()) already correctly copies vnet_hdr to a stack-local variable. All other vnet_hdr consumers in the kernel (tun.c, tap.c, virtio_net.c) also use stack copies. The TPACKET TX path is the only caller of virtio_net_hdr_to_skb() that reads directly from user-controlled shared memory. Fix this by copying vnet_hdr from the mmap'd ring buffer to a stack-local variable before validation and use, consistent with the approach used in packet_snd() and all other callers. Fixes: 1d036d25e5 ("packet: tpacket_snd gso and checksum offload") Signed-off-by: Bingquan Chen <patzilla007@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20260418112006.78823-1-patzilla007@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>		2026-04-22 20:16:34 -07:00
..
af_packet.c	net/packet: fix TOCTOU race on mmap'd vnet_hdr in tpacket_snd()	2026-04-22 20:16:34 -07:00
diag.c	net: change sock.sk_ino and sock_i_ino() to u64	2026-03-06 14:31:26 +01:00
internal.h	net: af_packet: Use hrtimer to do the retire operation	2025-09-11 18:40:06 -07:00
Kconfig	treewide: replace '---help---' in Kconfig files with 'help'	2020-06-14 01:57:21 +09:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00