Hello,
syzbot found the following crash on:
HEAD commit:b835a71e usbnet: smsc95xx: Fix use-after-free after removal
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=106721ad10
kernel config: https://syzkaller.appspot.com/x/.config?x=dcc6334acae363d4
dashboard link: https://syzkaller.appspot.com/bug?extid=4c8afc85aa32ddb020dc
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13c2541910
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1768f00910
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4c8afc85aa32ddb02...@syzkaller.appspotmail.com
netlink: 'syz-executor532': attribute type 3 has an invalid length.
==
BUG: KASAN: use-after-free in nla_len include/net/netlink.h:1135 [inline]
BUG: KASAN: use-after-free in nla_memcpy+0x9c/0xa0 lib/nlattr.c:724
Read of size 2 at addr 8880a46aec14 by task syz-executor532/6937
CPU: 1 PID: 6937 Comm: syz-executor532 Not tainted 5.8.0-rc1-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
nla_len include/net/netlink.h:1135 [inline]
nla_memcpy+0x9c/0xa0 lib/nlattr.c:724
nla_get_u64 include/net/netlink.h:1606 [inline]
nl802154_dump_wpan_phy_parse net/ieee802154/nl802154.c:559 [inline]
nl802154_dump_wpan_phy+0x59b/0x9c0 net/ieee802154/nl802154.c:593
genl_lock_dumpit+0x7f/0xb0 net/netlink/genetlink.c:575
netlink_dump+0x4cd/0xf60 net/netlink/af_netlink.c:2245
__netlink_dump_start+0x643/0x900 net/netlink/af_netlink.c:2353
genl_family_rcv_msg_dumpit+0x2ac/0x310 net/netlink/genetlink.c:638
genl_family_rcv_msg net/netlink/genetlink.c:733 [inline]
genl_rcv_msg+0x797/0x9e0 net/netlink/genetlink.c:753
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469
genl_rcv+0x24/0x40 net/netlink/genetlink.c:764
netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:672
sys_sendmsg+0x6e8/0x810 net/socket.c:2352
___sys_sendmsg+0xf3/0x170 net/socket.c:2406
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x441409
Code: Bad RIP value.
RSP: 002b:7ffda49cc2b8 EFLAGS: 0246 ORIG_RAX: 002e
RAX: ffda RBX: 0003 RCX: 00441409
RDX: RSI: 2000 RDI: 0003
RBP: 006cc018 R08: 000120080522 R09: 000120080522
R10: 0004 R11: 0246 R12: 00402220
R13: 004022b0 R14: R15:
Allocated by task 6962:
save_stack+0x1b/0x40 mm/kasan/common.c:48
set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
__kmalloc_reserve net/core/skbuff.c:142 [inline]
__alloc_skb+0xae/0x550 net/core/skbuff.c:210
alloc_skb include/linux/skbuff.h:1083 [inline]
netlink_alloc_large_skb net/netlink/af_netlink.c:1175 [inline]
netlink_sendmsg+0x94f/0xd90 net/netlink/af_netlink.c:1893
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:672
sys_sendmsg+0x6e8/0x810 net/socket.c:2352
___sys_sendmsg+0xf3/0x170 net/socket.c:2406
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 6962:
save_stack+0x1b/0x40 mm/kasan/common.c:48
set_track mm/kasan/common.c:56 [inline]
kasan_set_free_info mm/kasan/common.c:316 [inline]
__kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
__cache_free mm/slab.c:3426 [inline]
kfree+0x103/0x2c0 mm/slab.c:3757
skb_free_head net/core/skbuff.c:590 [inline]
skb_release_data+0x6d9/0x910 net/core/skbuff.c:610
skb_release_all net/core/skbuff.c:664 [inline]
__kfree_skb net/core/skbuff.c:678 [inline]
consume_skb net/core/skbuff.c:837 [inline]
consume_skb+0xc2/0x160 net/core/skbuff.c:831
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x53b/0x7d0 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:672
sys_sendmsg+0x6e8/0x810 net/socket.c:2352
___sys_sendmsg+0xf3/0x170 net/socket.c:2406
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy
