On 3/30/21 12:11 PM, Hao Sun wrote: > Hi > > When using Healer(https://github.com/SunHao-0/healer/tree/dev) to fuzz > the Linux kernel, I found a use-after-free vulnerability in > macvlan_broadcast. > Hope the report can help you locate the problem. > > Details: > commit: 5695e5161 Linux 5.11 > git tree: upstream > kernel config and reproducing program can be found in the attachment. > report: > ================================================================== > BUG: KASAN: use-after-free in macvlan_broadcast+0x595/0x6e0 > Read of size 4 at addr ffff88806ae70801 by task syz-executor392/8448 > > CPU: 0 PID: 8448 Comm: syz-executor392 Not tainted 5.4.0 #14 Why is 5.4.0 printed if your tree is linux-5.11 ? You describe something that has been fixed already in linux-5.5 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > 1.13.0-1ubuntu1.1 04/01/2014 > Call Trace: > dump_stack+0xf3/0x16a > print_address_description.constprop.0.cold+0xd3/0x372 > __kasan_report.cold+0x75/0x9b > kasan_report+0x12/0x20 > macvlan_broadcast+0x595/0x6e0 > macvlan_start_xmit+0x40e/0x630 > dev_direct_xmit+0x3f6/0x5f0 > packet_sendmsg+0x233b/0x5a60 > sock_sendmsg+0xd7/0x130 > __sys_sendto+0x21e/0x330 > __x64_sys_sendto+0xe1/0x1b0 > do_syscall_64+0xbf/0x640 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x453d6d > Code: c3 e8 77 2c 00 00 0f 1f 80 00 00 00 00 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 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fff89ba8378 EFLAGS: 00000246 ORIG_RAX: 000000000000002c > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000453d6d > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 > RBP: 0000000000000040 R08: 0000000020000280 R09: 0000000000000014 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 > R13: 00007fff89ba83e8 R14: 00007fff89ba83f0 R15: 0000000000000000 > > Allocated by task 8448: > save_stack+0x1b/0x80 > __kasan_kmalloc.constprop.0+0xc2/0xd0 > __kmalloc_node_track_caller+0x116/0x410 > __kmalloc_reserve.isra.0+0x35/0xd0 > __alloc_skb+0xf3/0x5c0 > rtmsg_fib+0x16f/0x11a0 > fib_table_insert+0x66e/0x1560 > fib_magic+0x406/0x570 > fib_add_ifaddr+0x39a/0x520 > fib_netdev_event+0x3d0/0x560 > notifier_call_chain+0xc0/0x230 > __dev_notify_flags+0x125/0x2d0 > dev_change_flags+0x104/0x160 > do_setlink+0x999/0x32a0 > __rtnl_newlink+0xac8/0x14c0 > rtnl_newlink+0x68/0xa0 > rtnetlink_rcv_msg+0x4a4/0xb70 > netlink_rcv_skb+0x15e/0x410 > netlink_unicast+0x4d4/0x690 > netlink_sendmsg+0x8ae/0xd00 > sock_sendmsg+0xd7/0x130 > __sys_sendto+0x21e/0x330 > __x64_sys_sendto+0xe1/0x1b0 > do_syscall_64+0xbf/0x640 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 8448: > save_stack+0x1b/0x80 > __kasan_slab_free+0x126/0x170 > kfree+0xfa/0x460 > skb_free_head+0x8b/0xa0 > pskb_expand_head+0x2bd/0xe80 > netlink_trim+0x203/0x260 > netlink_broadcast_filtered+0x61/0xbd0 > nlmsg_notify+0x15b/0x1a0 > rtmsg_fib+0x2eb/0x11a0 > fib_table_insert+0x66e/0x1560 > fib_magic+0x406/0x570 > fib_add_ifaddr+0x39a/0x520 > fib_netdev_event+0x3d0/0x560 > notifier_call_chain+0xc0/0x230 > __dev_notify_flags+0x125/0x2d0 > dev_change_flags+0x104/0x160 > do_setlink+0x999/0x32a0 > __rtnl_newlink+0xac8/0x14c0 > rtnl_newlink+0x68/0xa0 > rtnetlink_rcv_msg+0x4a4/0xb70 > netlink_rcv_skb+0x15e/0x410 > netlink_unicast+0x4d4/0x690 > netlink_sendmsg+0x8ae/0xd00 > sock_sendmsg+0xd7/0x130 > __sys_sendto+0x21e/0x330 > __x64_sys_sendto+0xe1/0x1b0 > do_syscall_64+0xbf/0x640 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff88806ae70800 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 1 bytes inside of > 1024-byte region [ffff88806ae70800, ffff88806ae70c00) > The buggy address belongs to the page: > page:ffffea0001ab9c00 refcount:1 mapcount:0 mapping:ffff88806b802280 > index:0x0 compound_mapcount: 0 > raw: 00fff00000010200 dead000000000100 dead000000000122 ffff88806b802280 > raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff88806ae70700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff88806ae70780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff88806ae70800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff88806ae70880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88806ae70900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== >
