af_packet: Don't send zero-byte data in packet_sendmsg_spkt(). ...
syzkaller reported a warning below [0].
We can reproduce it by sending 0-byte data from the (AF_PACKET,
SOCK_PACKET) socket via some devices whose dev->hard_header_len
is 0.
struct sockaddr_pkt addr = {
.spkt_family = AF_PACKET,
.spkt_device = "tun0",
};
int fd;
fd = socket(AF_PACKET, SOCK_PACKET, 0);
sendto(fd, NULL, 0, 0, (struct sockaddr *)&addr, sizeof(addr));
We have a similar fix for the (AF_PACKET, SOCK_RAW) socket as
commit dc633700f0#1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:skb_assert_len include/linux/skbuff.h:2552 [inline]
RIP: 0010:__dev_queue_xmit+0x1f26/0x31d0 net/core/dev.c:4159
Code: 89 de e8 1d a2 85 fd 84 db 75 21 e8 64 a9 85 fd 48 c7 c6 80 2a 1f 86 48 c7 c7 c0 06 1f 86 c6 05 23 cf 27 04 01 e8 fa ee 56 fd <0f> 0b e8 43 a9 85 fd 0f b6 1d 0f cf 27 04 31 ff 89 de e8 e3 a1 85
RSP: 0018:ffff8880217af6e0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90001133000
RDX: 0000000000040000 RSI: ffffffff81186922 RDI: 0000000000000001
RBP: ffff8880217af8b0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffff888030045640
R13: ffff8880300456b0 R14: ffff888030045650 R15: ffff888030045718
FS: 00007fc5864da640(0000) GS:ffff88806cd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020005740 CR3: 000000003f856003 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
dev_queue_xmit include/linux/netdevice.h:3085 [inline]
packet_sendmsg_spkt+0xc4b/0x1230 net/packet/af_packet.c:2066
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg+0x1b4/0x200 net/socket.c:747
____sys_sendmsg+0x331/0x970 net/socket.c:2503
___sys_sendmsg+0x11d/0x1c0 net/socket.c:2557
__sys_sendmmsg+0x18c/0x430 net/socket.c:2643
__do_sys_sendmmsg net/socket.c:2672 [inline]
__se_sys_sendmmsg net/socket.c:2669 [inline]
__x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2669
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3c/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7fc58791de5d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48
RSP: 002b:00007fc5864d9cc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004bbf80 RCX: 00007fc58791de5d
RDX: 0000000000000001 RSI: 0000000020005740 RDI: 0000000000000004
RBP: 00000000004bbf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fc58797e530 R15: 0000000000000000
</TASK>
---[ end trace 0000000000000000 ]---
skb len=0 headroom=16 headlen=0 tailroom=304
mac=(16,0) net=(16,-1) trans=-1
shinfo(txflags=0 nr_frags=0 gso(size=0 type=0 segs=0))
csum(0x0 ip_summed=0 complete_sw=0 valid=0 level=0)
hash(0x0 sw=0 l4=0) proto=0x0000 pkttype=0 iif=0
dev name=sit0 feat=0x00000006401d7869
sk family=17 type=10 proto=0
Fixes: 1da177e4c3
6a341729fb