netlink: 108 bytes leftover after parsing attributes in process `syz-executor.1'. ================================================================== BUG: KASAN: use-after-free in strcmp+0x90/0xb0 lib/string.c:364 Read of size 1 at addr ffff888068451018 by task syz-executor.1/17525 CPU: 1 PID: 17525 Comm: syz-executor.1 Not tainted 5.8.0-rc2-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 strcmp+0x90/0xb0 lib/string.c:364 devlink_get_from_attrs+0x1bf/0x2f0 net/core/devlink.c:137 devlink_nl_cmd_region_read_dumpit+0x177/0xed0 net/core/devlink.c:4395 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 sock_no_sendpage+0xee/0x130 net/core/sock.c:2853 kernel_sendpage net/socket.c:3642 [inline] sock_sendpage+0xe5/0x140 net/socket.c:945 pipe_to_sendpage+0x2ad/0x380 fs/splice.c:448 splice_from_pipe_feed fs/splice.c:502 [inline] __splice_from_pipe+0x3dc/0x830 fs/splice.c:626 splice_from_pipe fs/splice.c:661 [inline] generic_splice_sendpage+0xd4/0x140 fs/splice.c:834 do_splice_from fs/splice.c:846 [inline] direct_splice_actor+0x171/0x2f0 fs/splice.c:1016 splice_direct_to_actor+0x38c/0x980 fs/splice.c:971 do_splice_direct+0x1b3/0x280 fs/splice.c:1059 do_sendfile+0x559/0xc30 fs/read_write.c:1521 __do_sys_sendfile64 fs/read_write.c:1582 [inline] __se_sys_sendfile64 fs/read_write.c:1568 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1568 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f2cef141c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000004fd720 RCX: 000000000045cb29 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000006 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000100000001 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000902 R14: 00000000004cbe0a R15: 00007f2cef1426d4 Allocated by task 17552: 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 17552: 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 address belongs to the object at ffff888068451000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of 512-byte region [ffff888068451000, ffff888068451200) The buggy address belongs to the page: page:ffffea0001a11440 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00028b2388 ffffea0002774288 ffff8880aa000a80 raw: 0000000000000000 ffff888068451000 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888068450f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888068450f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888068451000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888068451080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888068451100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================