netlink: 20 bytes leftover after parsing attributes in process `syz-executor.2'. ================================================================== BUG: KASAN: use-after-free in nla_parse_nested_deprecated include/net/netlink.h:1218 [inline] BUG: KASAN: use-after-free in tipc_udp_nl_dump_remoteip+0xb92/0xba0 net/tipc/udp_media.c:467 Read of size 2 at addr ffff8880a87e3014 by task syz-executor.2/17246 CPU: 1 PID: 17246 Comm: syz-executor.2 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+0xd3/0x413 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 nla_parse_nested_deprecated include/net/netlink.h:1218 [inline] tipc_udp_nl_dump_remoteip+0xb92/0xba0 net/tipc/udp_media.c:467 genl_lock_dumpit+0x7f/0xb0 net/netlink/genetlink.c:575 netlink_dump+0x50b/0xe70 net/netlink/af_netlink.c:2245 __netlink_dump_start+0x63f/0x910 net/netlink/af_netlink.c:2353 genl_family_rcv_msg_dumpit.isra.0+0x296/0x300 net/netlink/genetlink.c:638 genl_family_rcv_msg net/netlink/genetlink.c:733 [inline] genl_rcv_msg+0x781/0x9c0 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+0x537/0x740 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352 ___sys_sendmsg+0x100/0x170 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: 0033:0x45ca59 Code: Bad RIP value. RSP: 002b:00007f7c015f6c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000005017e0 RCX: 000000000045ca59 RDX: 0000000000000000 RSI: 0000000020000200 RDI: 0000000000000003 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000a15 R14: 00000000004d69a8 R15: 00007f7c015f76d4 Allocated by task 17254: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc mm/kasan/common.c:494 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467 __kmalloc_reserve.isra.0+0x39/0xe0 net/core/skbuff.c:142 __alloc_skb+0xef/0x5a0 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+0x97b/0xe10 net/netlink/af_netlink.c:1893 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352 ___sys_sendmsg+0x100/0x170 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 17254: 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+0xf7/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kfree+0x109/0x2b0 mm/slab.c:3757 skb_free_head+0x8b/0xa0 net/core/skbuff.c:590 skb_release_data+0x617/0x8a0 net/core/skbuff.c:610 skb_release_all+0x46/0x60 net/core/skbuff.c:664 __kfree_skb net/core/skbuff.c:678 [inline] consume_skb net/core/skbuff.c:837 [inline] consume_skb+0xf3/0x3f0 net/core/skbuff.c:831 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x53f/0x740 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352 ___sys_sendmsg+0x100/0x170 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 address belongs to the object at ffff8880a87e3000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 20 bytes inside of 512-byte region [ffff8880a87e3000, ffff8880a87e3200) The buggy address belongs to the page: page:ffffea0002a1f8c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a87e3400 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea000228b1c8 ffffea000289fb48 ffff8880aa000a80 raw: ffff8880a87e3400 ffff8880a87e3000 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a87e2f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a87e2f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880a87e3000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a87e3080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a87e3100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================