R10: 0000000000200fc0 R11: 0000000000000246 R12: 0000000000000027 R13: 00007fffbe61159f R14: 00007f8f575079c0 R15: 000000000118bf2c tipc: Failed do clone local mcast rcv buffer ================================================================== BUG: KASAN: use-after-free in __skb_unlink include/linux/skbuff.h:2031 [inline] BUG: KASAN: use-after-free in __skb_dequeue include/linux/skbuff.h:2050 [inline] BUG: KASAN: use-after-free in __skb_queue_purge include/linux/skbuff.h:2761 [inline] BUG: KASAN: use-after-free in tipc_mcast_xmit+0x101f/0x1690 net/tipc/bcast.c:421 Read of size 8 at addr ffff8881d7012780 by task syz-executor.4/15963 CPU: 1 PID: 15963 Comm: syz-executor.4 Not tainted 5.4.68-syzkaller-00471-g6fa60aa03b21 #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+0x1b0/0x21e lib/dump_stack.c:118 print_address_description+0x96/0x5d0 mm/kasan/report.c:374 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506 kasan_report+0x27/0x50 mm/kasan/common.c:634 __skb_unlink include/linux/skbuff.h:2031 [inline] __skb_dequeue include/linux/skbuff.h:2050 [inline] __skb_queue_purge include/linux/skbuff.h:2761 [inline] tipc_mcast_xmit+0x101f/0x1690 net/tipc/bcast.c:421 tipc_sendmcast+0xc00/0xeb0 net/tipc/socket.c:819 __tipc_sendmsg+0x120d/0x2ce0 net/tipc/socket.c:1357 tipc_sendmsg+0x51/0x70 net/tipc/socket.c:1290 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg net/socket.c:658 [inline] kernel_sendmsg+0xe2/0x120 net/socket.c:678 sock_no_sendpage+0x13f/0x1b0 net/core/sock.c:2768 kernel_sendpage net/socket.c:3764 [inline] sock_sendpage+0xd0/0x120 net/socket.c:936 pipe_to_sendpage+0x23b/0x300 fs/splice.c:449 splice_from_pipe_feed fs/splice.c:500 [inline] __splice_from_pipe+0x2d3/0x870 fs/splice.c:624 splice_from_pipe fs/splice.c:659 [inline] generic_splice_sendpage+0x172/0x200 fs/splice.c:829 splice_direct_to_actor+0x496/0xb00 fs/splice.c:976 do_splice_direct+0x279/0x3d0 fs/splice.c:1064 do_sendfile+0x89d/0x1110 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1ae/0x220 fs/read_write.c:1511 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45dd99 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8f57506c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000027ec0 RCX: 000000000045dd99 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 00007f8f57506ca0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000200fc0 R11: 0000000000000246 R12: 0000000000000027 R13: 00007fffbe61159f R14: 00007f8f575079c0 R15: 000000000118bf2c Allocated by task 15963: save_stack mm/kasan/common.c:69 [inline] set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc+0x117/0x1b0 mm/kasan/common.c:510 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2793 [inline] slab_alloc mm/slub.c:2801 [inline] kmem_cache_alloc+0x1d5/0x250 mm/slub.c:2806 kmem_cache_alloc_node include/linux/slab.h:427 [inline] __alloc_skb+0x88/0x4d0 net/core/skbuff.c:198 alloc_skb_fclone include/linux/skbuff.h:1107 [inline] tipc_buf_acquire net/tipc/msg.c:66 [inline] tipc_msg_build+0x727/0x1a60 net/tipc/msg.c:368 tipc_sendmcast+0x92a/0xeb0 net/tipc/socket.c:813 __tipc_sendmsg+0x120d/0x2ce0 net/tipc/socket.c:1357 tipc_sendmsg+0x51/0x70 net/tipc/socket.c:1290 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg net/socket.c:658 [inline] kernel_sendmsg+0xe2/0x120 net/socket.c:678 sock_no_sendpage+0x13f/0x1b0 net/core/sock.c:2768 kernel_sendpage net/socket.c:3764 [inline] sock_sendpage+0xd0/0x120 net/socket.c:936 pipe_to_sendpage+0x23b/0x300 fs/splice.c:449 splice_from_pipe_feed fs/splice.c:500 [inline] __splice_from_pipe+0x2d3/0x870 fs/splice.c:624 splice_from_pipe fs/splice.c:659 [inline] generic_splice_sendpage+0x172/0x200 fs/splice.c:829 splice_direct_to_actor+0x496/0xb00 fs/splice.c:976 do_splice_direct+0x279/0x3d0 fs/splice.c:1064 do_sendfile+0x89d/0x1110 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1ae/0x220 fs/read_write.c:1511 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 15963: save_stack mm/kasan/common.c:69 [inline] set_track mm/kasan/common.c:77 [inline] kasan_set_free_info mm/kasan/common.c:332 [inline] __kasan_slab_free+0x168/0x220 mm/kasan/common.c:471 slab_free_hook mm/slub.c:1443 [inline] slab_free_freelist_hook+0xd0/0x150 mm/slub.c:1476 slab_free mm/slub.c:3041 [inline] kmem_cache_free+0xac/0x5c0 mm/slub.c:3057 tipc_buf_append+0x2d1/0xad0 net/tipc/msg.c:188 tipc_msg_reassemble+0x331/0x590 net/tipc/msg.c:726 tipc_mcast_xmit+0x223/0x1690 net/tipc/bcast.c:385 tipc_sendmcast+0xc00/0xeb0 net/tipc/socket.c:819 __tipc_sendmsg+0x120d/0x2ce0 net/tipc/socket.c:1357 tipc_sendmsg+0x51/0x70 net/tipc/socket.c:1290 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg net/socket.c:658 [inline] kernel_sendmsg+0xe2/0x120 net/socket.c:678 sock_no_sendpage+0x13f/0x1b0 net/core/sock.c:2768 kernel_sendpage net/socket.c:3764 [inline] sock_sendpage+0xd0/0x120 net/socket.c:936 pipe_to_sendpage+0x23b/0x300 fs/splice.c:449 splice_from_pipe_feed fs/splice.c:500 [inline] __splice_from_pipe+0x2d3/0x870 fs/splice.c:624 splice_from_pipe fs/splice.c:659 [inline] generic_splice_sendpage+0x172/0x200 fs/splice.c:829 splice_direct_to_actor+0x496/0xb00 fs/splice.c:976 do_splice_direct+0x279/0x3d0 fs/splice.c:1064 do_sendfile+0x89d/0x1110 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1ae/0x220 fs/read_write.c:1511 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8881d7012780 which belongs to the cache skbuff_fclone_cache of size 488 The buggy address is located 0 bytes inside of 488-byte region [ffff8881d7012780, ffff8881d7012968) The buggy address belongs to the page: page:ffffea00075c0480 refcount:1 mapcount:0 mapping:ffff8881daa92a00 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 ffffea000592f500 0000000d0000000d ffff8881daa92a00 raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881d7012680: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff8881d7012700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881d7012780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d7012800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d7012880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle page fault for address: ffff88817d64c400 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0011) - permissions violation PGD 6001067 P4D 6001067 PUD 17f07a063 PMD 800000017d6001e3 Oops: 0011 [#1] PREEMPT SMP KASAN CPU: 0 PID: 15963 Comm: syz-executor.4 Tainted: G B 5.4.68-syzkaller-00471-g6fa60aa03b21 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:0xffff88817d64c400 Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> e1 0e c7 81 88 ff ff a3 a9 a4 fc 9f 55 00 00 00 00 00 00 00 00 RSP: 0018:ffff8881d47bee98 EFLAGS: 00010296 RAX: c935378c686f9e00 RBX: 1ffff1103b273b1c RCX: ffffffff83214a84 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881d939d880 RBP: 0000000000000000 R08: ffffffff83214a64 R09: 0000000000000007 R10: ffffed103b273b2d R11: 00000000000000fb R12: dffffc0000000000 R13: 1ffff1103b273b1b R14: ffff8881d939d880 R15: ffff8881d939d8e0 FS: 00007f8f57507700(0000) GS:ffff8881db800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88817d64c400 CR3: 00000001a0d34005 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: Modules linked in: CR2: ffff88817d64c400 ---[ end trace fdddc2b7398a34de ]--- RIP: 0010:0xffff88817d64c400 Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> e1 0e c7 81 88 ff ff a3 a9 a4 fc 9f 55 00 00 00 00 00 00 00 00 RSP: 0018:ffff8881d47bee98 EFLAGS: 00010296 RAX: c935378c686f9e00 RBX: 1ffff1103b273b1c RCX: ffffffff83214a84 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881d939d880 RBP: 0000000000000000 R08: ffffffff83214a64 R09: 0000000000000007 R10: ffffed103b273b2d R11: 00000000000000fb R12: dffffc0000000000 R13: 1ffff1103b273b1b R14: ffff8881d939d880 R15: ffff8881d939d8e0 FS: 00007f8f57507700(0000) GS:ffff8881db800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88817d64c400 CR3: 00000001a0d34005 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400