Subject: CVE-2024-44999: gtp: pull network headers in gtp_dev_xmit()

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

gtp: pull network headers in gtp_dev_xmit()

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

The Linux kernel CVE team has assigned CVE-2024-44999 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 4.19.321 with commit 3d89d0c4a1c6
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 5.4.283 with commit f5dda8db382c
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 5.10.225 with commit cbb9a969fc19
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 5.15.166 with commit 1f6b62392453
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 6.1.107 with commit 137d565ab89c
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 6.6.48 with commit 34ba4f29f3d9
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 6.10.7 with commit 3939d787139e
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 6.11 with commit 3a3be7ff9224

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-44999
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/gtp.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/3d89d0c4a1c6d4d2a755e826351b0a101dbc86f3
	https://git.kernel.org/stable/c/f5dda8db382c5751c4e572afc7c99df7da1f83ca
	https://git.kernel.org/stable/c/cbb9a969fc190e85195d1b0f08038e7f6199044e
	https://git.kernel.org/stable/c/1f6b62392453d8f36685d19b761307a8c5617ac1
	https://git.kernel.org/stable/c/137d565ab89ce3584503b443bc9e00d44f482593
	https://git.kernel.org/stable/c/34ba4f29f3d9eb52dee37512059efb2afd7e966f
	https://git.kernel.org/stable/c/3939d787139e359b77aaf9485d1e145d6713d7b9
	https://git.kernel.org/stable/c/3a3be7ff9224f424e485287b54be00d2c6bd9c40