================================================================== BUG: KASAN: double-free or invalid-free in security_tun_dev_free_security+0x3e/0x70 security/security.c:2342 CPU: 0 PID: 27606 Comm: syz-executor.5 Not tainted 5.16.0-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:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x2ed mm/kasan/report.c:247 kasan_report_invalid_free+0x51/0x80 mm/kasan/report.c:372 ____kasan_slab_free mm/kasan/common.c:346 [inline] __kasan_slab_free+0xf6/0x110 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:235 [inline] __cache_free mm/slab.c:3445 [inline] kfree+0x10d/0x2c0 mm/slab.c:3802 security_tun_dev_free_security+0x3e/0x70 security/security.c:2342 tun_free_netdev+0xdc/0x140 drivers/net/tun.c:2215 netdev_run_todo+0x6b4/0xa80 net/core/dev.c:10627 __tun_chr_ioctl.isra.0+0x9a1/0x4230 drivers/net/tun.c:3302 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fcf502c3ae9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fcf4d818188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fcf503d7020 RCX: 00007fcf502c3ae9 RDX: 0000000020000000 RSI: 00000000400454ca RDI: 0000000000000003 RBP: 00007fcf5031df6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc7fc286bf R14: 00007fcf4d818300 R15: 0000000000022000 Allocated by task 27606: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] ____kasan_kmalloc mm/kasan/common.c:472 [inline] __kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:522 kasan_kmalloc include/linux/kasan.h:269 [inline] kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3575 kmalloc include/linux/slab.h:590 [inline] kzalloc include/linux/slab.h:724 [inline] selinux_tun_dev_alloc_security+0x43/0x180 security/selinux/hooks.c:5594 security_tun_dev_alloc_security+0x40/0x90 security/security.c:2336 __tun_chr_ioctl.isra.0+0x27e6/0x4230 drivers/net/tun.c:2727 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 27606: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xd1/0x110 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:235 [inline] __cache_free mm/slab.c:3445 [inline] kfree+0x10d/0x2c0 mm/slab.c:3802 security_tun_dev_free_security+0x3e/0x70 security/security.c:2342 __tun_chr_ioctl.isra.0+0x2cbf/0x4230 drivers/net/tun.c:2782 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff8880669e9140 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 0 bytes inside of 32-byte region [ffff8880669e9140, ffff8880669e9160) The buggy address belongs to the page: page:ffffea00019a7a40 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880669e9fc1 pfn:0x669e9 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0001b23dc8 ffffea000080a208 ffff888010c40100 raw: ffff8880669e9fc1 ffff8880669e9000 0000000100000034 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x3420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_HARDWALL|__GFP_THISNODE), pid 16986, ts 1379900048577, free_ts 1379895021866 prep_new_page mm/page_alloc.c:2418 [inline] get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4149 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369 __alloc_pages_node include/linux/gfp.h:570 [inline] kmem_getpages mm/slab.c:1377 [inline] cache_grow_begin+0x75/0x470 mm/slab.c:2593 cache_alloc_refill+0x27f/0x380 mm/slab.c:2965 ____cache_alloc mm/slab.c:3048 [inline] ____cache_alloc mm/slab.c:3031 [inline] __do_cache_alloc mm/slab.c:3275 [inline] slab_alloc mm/slab.c:3316 [inline] __do_kmalloc mm/slab.c:3700 [inline] __kmalloc_track_caller+0x3b0/0x4d0 mm/slab.c:3717 kvasprintf+0xb5/0x150 lib/kasprintf.c:25 kasprintf+0xbb/0xf0 lib/kasprintf.c:59 device_get_devnode+0xaa/0x2b0 drivers/base/core.c:3668 dev_uevent+0x41c/0x780 drivers/base/core.c:2305 uevent_show+0x1bb/0x390 drivers/base/core.c:2393 dev_attr_show+0x4b/0x90 drivers/base/core.c:2095 sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59 seq_read_iter+0x4f6/0x1240 fs/seq_file.c:230 kernfs_fop_read_iter+0x44f/0x5f0 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2156 [inline] new_sync_read+0x421/0x6e0 fs/read_write.c:400 vfs_read+0x35c/0x600 fs/read_write.c:481 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1338 [inline] free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1389 free_unref_page_prepare mm/page_alloc.c:3309 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3388 mm_free_pgd kernel/fork.c:647 [inline] __mmdrop+0xcb/0x3f0 kernel/fork.c:698 mmdrop include/linux/sched/mm.h:49 [inline] __mmput+0x3f1/0x4b0 kernel/fork.c:1123 mmput+0x56/0x60 kernel/fork.c:1134 free_bprm+0x65/0x2e0 fs/exec.c:1481 kernel_execve+0x380/0x460 fs/exec.c:1978 call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Memory state around the buggy address: ffff8880669e9000: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ffff8880669e9080: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc >ffff8880669e9100: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff8880669e9180: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ffff8880669e9200: fb fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ==================================================================