6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
commit 3a3be7ff9224f424e485287b54be00d2c6bd9c40 upstream.
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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/gtp.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -901,6 +901,9 @@ static netdev_tx_t gtp_dev_xmit(struct s
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. */
