3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 4ffcbfac60642f63ae3d80891f573ba7e94a265c ]
KMSAN reported batadv_interface_tx() was possibly using a
garbage value [1]
batadv_get_vid() does have a pskb_may_pull() call
but batadv_interface_tx() does not actually make sure
this did not fail.
[1]
BUG: KMSAN: uninit-value in batadv_interface_tx+0x908/0x1e40 net/batman-adv/soft-interface.c:231
CPU: 0 PID: 10006 Comm: syz-executor469 Not tainted 4.20.0-rc7+ #5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x173/0x1d0 lib/dump_stack.c:113
kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613
__msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:313
batadv_interface_tx+0x908/0x1e40 net/batman-adv/soft-interface.c:231
__netdev_start_xmit include/linux/netdevice.h:4356 [inline]
netdev_start_xmit include/linux/netdevice.h:4365 [inline]
xmit_one net/core/dev.c:3257 [inline]
dev_hard_start_xmit+0x607/0xc40 net/core/dev.c:3273
__dev_queue_xmit+0x2e42/0x3bc0 net/core/dev.c:3843
dev_queue_xmit+0x4b/0x60 net/core/dev.c:3876
packet_snd net/packet/af_packet.c:2928 [inline]
packet_sendmsg+0x8306/0x8f30 net/packet/af_packet.c:2953
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg net/socket.c:631 [inline]
__sys_sendto+0x8c4/0xac0 net/socket.c:1788
__do_sys_sendto net/socket.c:1800 [inline]
__se_sys_sendto+0x107/0x130 net/socket.c:1796
__x64_sys_sendto+0x6e/0x90 net/socket.c:1796
do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x441889
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffdda6fd468 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000441889
RDX: 000000000000000e RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 00007ffdda6fd4c0
R13: 00007ffdda6fd4b0 R14: 0000000000000000 R15: 0000000000000000
Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline]
kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:158
kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176
kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:185
slab_post_alloc_hook mm/slab.h:446 [inline]
slab_alloc_node mm/slub.c:2759 [inline]
__kmalloc_node_track_caller+0xe18/0x1030 mm/slub.c:4383
__kmalloc_reserve net/core/skbuff.c:137 [inline]
__alloc_skb+0x309/0xa20 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:998 [inline]
alloc_skb_with_frags+0x1c7/0xac0 net/core/skbuff.c:5220
sock_alloc_send_pskb+0xafd/0x10e0 net/core/sock.c:2083
packet_alloc_skb net/packet/af_packet.c:2781 [inline]
packet_snd net/packet/af_packet.c:2872 [inline]
packet_sendmsg+0x661a/0x8f30 net/packet/af_packet.c:2953
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg net/socket.c:631 [inline]
__sys_sendto+0x8c4/0xac0 net/socket.c:1788
__do_sys_sendto net/socket.c:1800 [inline]
__se_sys_sendto+0x107/0x130 net/socket.c:1796
__x64_sys_sendto+0x6e/0x90 net/socket.c:1796
do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
entry_SYSCALL_64_after_hwframe+0x63/0xe7
Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Cc: Marek Lindner <mareklindner@xxxxxxxxxxxxx>
Cc: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
Cc: Antonio Quartulli <a@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/batman-adv/soft-interface.c | 2 ++
1 file changed, 2 insertions(+)
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -186,6 +186,8 @@ static int batadv_interface_tx(struct sk
switch (ntohs(ethhdr->h_proto)) {
case ETH_P_8021Q:
+ if (!pskb_may_pull(skb, sizeof(*vhdr)))
+ goto dropped;
vhdr = vlan_eth_hdr(skb);
if (vhdr->h_vlan_encapsulated_proto != ethertype) {
