Hi Sasha, Greg, Could you cherry-pick this patch for other -stable kernels? I confirm this applies up to >= 4.19-stable since it already includes pskb_inet_may_pull(). Thanks. On Mon, Aug 19, 2024 at 10:20:22AM -0400, Sasha Levin wrote: > This is a note to let you know that I've just added the patch titled > > gtp: pull network headers in gtp_dev_xmit() > > to the 6.10-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > gtp-pull-network-headers-in-gtp_dev_xmit.patch > and it can be found in the queue-6.10 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. > > > > commit 70c490935879f95a7d81403d107e7aa9a0bd7b31 > Author: Eric Dumazet <edumazet@xxxxxxxxxx> > Date: Thu Aug 8 13:24:55 2024 +0000 > > gtp: pull network headers in gtp_dev_xmit() > > [ Upstream commit 3a3be7ff9224f424e485287b54be00d2c6bd9c40 ] > > 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 <edumazet@xxxxxxxxxx> > Cc: Harald Welte <laforge@xxxxxxxxxxxx> > Reviewed-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> > Link: https://patch.msgid.link/20240808132455.3413916-1-edumazet@xxxxxxxxxx > Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c > index 427b91aca50d3..0696faf60013e 100644 > --- a/drivers/net/gtp.c > +++ b/drivers/net/gtp.c > @@ -1269,6 +1269,9 @@ static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev) > if (skb_cow_head(skb, dev->needed_headroom)) > goto tx_err; > > + if (!pskb_inet_may_pull(skb)) > + goto tx_err; > + > skb_reset_inner_headers(skb); > > /* PDP context lookups in gtp_build_skb_*() need rcu read-side lock. */
