CVE-2024-44999

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

gtp: pull network headers in gtpdevxmit()

syzbot/KMSAN reported use of uninit-value in getdevxmit() [1]

We must make sure the IPv4 or Ipv6 header is pulled in skb->head before accessing fields in them.

Use pskbinetmay_pull() to fix this issue.

[1] BUG: KMSAN: uninit-value in ipv6pdpfind drivers/net/gtp.c:220 [inline] BUG: KMSAN: uninit-value in gtpbuildskbip6 drivers/net/gtp.c:1229 [inline] BUG: KMSAN: uninit-value in gtpdevxmit+0x1424/0x2540 drivers/net/gtp.c:1281 ipv6pdpfind drivers/net/gtp.c:220 [inline] gtpbuildskbip6 drivers/net/gtp.c:1229 [inline] gtpdevxmit+0x1424/0x2540 drivers/net/gtp.c:1281 __netdevstartxmit include/linux/netdevice.h:4913 [inline] netdevstartxmit include/linux/netdevice.h:4922 [inline] xmitone net/core/dev.c:3580 [inline] devhardstartxmit+0x247/0xa20 net/core/dev.c:3596 __devqueuexmit+0x358c/0x5610 net/core/dev.c:4423 devqueuexmit include/linux/netdevice.h:3105 [inline] packetxmit+0x9c/0x6c0 net/packet/afpacket.c:276 packetsnd net/packet/afpacket.c:3145 [inline] packetsendmsg+0x90e3/0xa3a0 net/packet/afpacket.c:3177 socksendmsgnosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 __sys_sendto+0x685/0x830 net/socket.c:2204 __dosyssendto net/socket.c:2216 [inline] __sesyssendto net/socket.c:2212 [inline] _x64syssendto+0x125/0x1d0 net/socket.c:2212 x64syscall+0x3799/0x3c10 arch/x86/include/generated/asm/syscalls64.h:45 dosyscallx64 arch/x86/entry/common.c:52 [inline] dosyscall64+0xcd/0x1e0 arch/x86/entry/common.c:83 entrySYSCALL64afterhwframe+0x77/0x7f

Uninit was created at: slabpostallochook mm/slub.c:3994 [inline] slaballocnode mm/slub.c:4037 [inline] kmemcacheallocnodenoprof+0x6bf/0xb80 mm/slub.c:4080 kmallocreserve+0x13d/0x4a0 net/core/skbuff.c:583 __allocskb+0x363/0x7b0 net/core/skbuff.c:674 allocskb include/linux/skbuff.h:1320 [inline] alloc_skbwithfrags+0xc8/0xbf0 net/core/skbuff.c:6526 sockallocsendpskb+0xa81/0xbf0 net/core/sock.c:2815 packetallocskb net/packet/afpacket.c:2994 [inline] packetsnd net/packet/afpacket.c:3088 [inline] packetsendmsg+0x749c/0xa3a0 net/packet/afpacket.c:3177 socksendmsgnosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 __sys_sendto+0x685/0x830 net/socket.c:2204 __dosyssendto net/socket.c:2216 [inline] __sesyssendto net/socket.c:2212 [inline] _x64syssendto+0x125/0x1d0 net/socket.c:2212 x64syscall+0x3799/0x3c10 arch/x86/include/generated/asm/syscalls64.h:45 dosyscallx64 arch/x86/entry/common.c:52 [inline] dosyscall64+0xcd/0x1e0 arch/x86/entry/common.c:83 entrySYSCALL64afterhwframe+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