4.9-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ 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@google.com Reported-by: syzbot syzkaller@googlegroups.com Cc: Marek Lindner mareklindner@neomailbox.ch Cc: Simon Wunderlich sw@simonwunderlich.de Cc: Antonio Quartulli a@unstable.cc Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -217,6 +217,8 @@ 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);
/* drop batman-in-batman packets to prevent loops */