WARNING in wiphy_register (2)

WARNING in wiphy_register (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    ec0c96714e7d Merge git://git.kernel.org/pub/scm/linux/kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17b01274400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=152cb8ccd35b1f70
dashboard link: https://syzkaller.appspot.com/bug?extid=2a12f11c306afe871c1f
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=10b2a2f8400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14ff3622400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2a12f11c306afe871c1f@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
netlink: 'syz-executor064': attribute type 9 has an invalid length.
WARNING: CPU: 0 PID: 4439 at net/wireless/core.c:550  
wiphy_verify_combinations net/wireless/core.c:550 [inline]
WARNING: CPU: 0 PID: 4439 at net/wireless/core.c:550  
wiphy_register+0x12c1/0x2510 net/wireless/core.c:741
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 4439 Comm: syz-executor064 Not tainted 4.18.0-rc8+ #184
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+0x1c9/0x2b4 lib/dump_stack.c:113
  panic+0x238/0x4e7 kernel/panic.c:184
  __warn.cold.8+0x163/0x1ba kernel/panic.c:536
  report_bug+0x252/0x2d0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:178 [inline]
  do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:wiphy_verify_combinations net/wireless/core.c:550 [inline]
RIP: 0010:wiphy_register+0x12c1/0x2510 net/wireless/core.c:741
Code: 74 08 3c 01 0f 8e c5 10 00 00 66 45 89 67 30 e9 18 f9 ff ff e8 40 00  
4c fb 0f 0b bb ea ff ff ff e9 f5 f3 ff ff e8 2f 00 4c fb <0f> 0b bb ea ff  
ff ff e9 e4 f3 ff ff e8 1e 00 4c fb 0f 0b bb ea ff
RSP: 0018:ffff8801ac51ee60 EFLAGS: 00010293
RAX: ffff8801af3fc700 RBX: 0000000000000000 RCX: ffffffff86301238
RDX: 0000000000000000 RSI: ffffffff86301821 RDI: 0000000000000005
RBP: ffff8801ac51f000 R08: ffff8801af3fc700 R09: ffffed00358d6114
R10: ffffed00358d6114 R11: ffff8801ac6b08a5 R12: ffff8801ac6b327c
R13: ffffffff87838ae0 R14: dffffc0000000000 R15: ffff8801ac6b08a0
  ieee80211_register_hw+0x13d5/0x35e0 net/mac80211/main.c:1050
  mac80211_hwsim_new_radio+0x1db8/0x33b0  
drivers/net/wireless/mac80211_hwsim.c:2772
  hwsim_new_radio_nl+0x7c0/0xa80 drivers/net/wireless/mac80211_hwsim.c:3247
  genl_family_rcv_msg+0x8a3/0x1140 net/netlink/genetlink.c:601
  genl_rcv_msg+0xc6/0x168 net/netlink/genetlink.c:626
  netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2455
  genl_rcv+0x28/0x40 net/netlink/genetlink.c:637
  netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
  netlink_unicast+0x5a0/0x760 net/netlink/af_netlink.c:1343
  netlink_sendmsg+0xa18/0xfd0 net/netlink/af_netlink.c:1908
  sock_sendmsg_nosec net/socket.c:642 [inline]
  sock_sendmsg+0xd5/0x120 net/socket.c:652
  ___sys_sendmsg+0x7fd/0x930 net/socket.c:2126
  __sys_sendmsg+0x11d/0x290 net/socket.c:2164
  __do_sys_sendmsg net/socket.c:2173 [inline]
  __se_sys_sendmsg net/socket.c:2171 [inline]
  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2171
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4402c9
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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcf9426d68 EFLAGS: 00000213 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004402c9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401b50
R13: 0000000000401be0 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with  
syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[PATCH] mac80211_hwsim: require at least one channel

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

Syzbot continues to try to create mac80211_hwsim radios, and
manages to pass parameters that are later checked with WARN_ON
in cfg80211 - catch another one in hwsim directly.

Reported-by: syzbot+2a12f11c306afe871c1f@syzkaller.appspotmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/mac80211_hwsim.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 18e819d964f1..fe1b0108f06d 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -3194,6 +3194,11 @@ static int hwsim_new_radio_nl(struct sk_buff *msg, struct genl_info *info)
 	if (info->attrs[HWSIM_ATTR_CHANNELS])
 		param.channels = nla_get_u32(info->attrs[HWSIM_ATTR_CHANNELS]);
 
+	if (param.channels < 1) {
+		GENL_SET_ERR_MSG(info, "must have at least one channel");
+		return -EINVAL;
+	}
+
 	if (param.channels > CFG80211_MAX_NUM_DIFFERENT_CHANNELS) {
 		GENL_SET_ERR_MSG(info, "too many channels specified");
 		return -EINVAL;
-- 
2.14.4