Messages in this thread | | | From | Dmitry Vyukov <> | Date | Thu, 7 Jun 2018 18:58:32 +0200 | Subject | Re: KASAN: use-after-free Write in bpf_tcp_close |
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On Mon, May 28, 2018 at 12:15 AM, Daniel Borkmann <daniel@iogearbox.net> wrote: > [ +John ] > > On 05/27/2018 10:06 PM, syzbot wrote: >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: ff4fb475cea8 Merge branch 'btf-uapi-cleanups' >> git tree: bpf-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=12b3d577800000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=b632d8e2c2ab2c1 >> dashboard link: https://syzkaller.appspot.com/bug?extid=31025a5f3f7650081204 >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >> syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=109a2f37800000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=171a727b800000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+31025a5f3f7650081204@syzkaller.appspotmail.com > > Should be fixed by: https://patchwork.ozlabs.org/patch/920695/
#syz fix: bpf: sockhash fix race with bpf_tcp_close and map delete
>> ================================================================== >> BUG: KASAN: use-after-free in cmpxchg_size include/asm-generic/atomic-instrumented.h:355 [inline] >> BUG: KASAN: use-after-free in bpf_tcp_close+0x6f5/0xf80 kernel/bpf/sockmap.c:265 >> Write of size 8 at addr ffff8801ca277680 by task syz-executor749/9723 >> >> CPU: 0 PID: 9723 Comm: syz-executor749 Not tainted 4.17.0-rc4+ #19 >> 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+0x1b9/0x294 lib/dump_stack.c:113 >> print_address_description+0x6c/0x20b mm/kasan/report.c:256 >> kasan_report_error mm/kasan/report.c:354 [inline] >> kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 >> check_memory_region_inline mm/kasan/kasan.c:260 [inline] >> check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 >> kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278 >> cmpxchg_size include/asm-generic/atomic-instrumented.h:355 [inline] >> bpf_tcp_close+0x6f5/0xf80 kernel/bpf/sockmap.c:265 >> inet_release+0x104/0x1f0 net/ipv4/af_inet.c:427 >> inet6_release+0x50/0x70 net/ipv6/af_inet6.c:459 >> sock_release+0x96/0x1b0 net/socket.c:594 >> sock_close+0x16/0x20 net/socket.c:1149 >> __fput+0x34d/0x890 fs/file_table.c:209 >> ____fput+0x15/0x20 fs/file_table.c:243 >> task_work_run+0x1e4/0x290 kernel/task_work.c:113 >> exit_task_work include/linux/task_work.h:22 [inline] >> do_exit+0x1aee/0x2730 kernel/exit.c:865 >> do_group_exit+0x16f/0x430 kernel/exit.c:968 >> __do_sys_exit_group kernel/exit.c:979 [inline] >> __se_sys_exit_group kernel/exit.c:977 [inline] >> __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:977 >> do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x440a59 >> RSP: 002b:00007ffdadf92488 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7 >> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440a59 >> RDX: 0000000000440a59 RSI: 0000000000000020 RDI: 0000000000000000 >> RBP: 0000000000000000 R08: 00000000004002c8 R09: 0000000000401ea0 >> R10: 00000000004002c8 R11: 0000000000000206 R12: 000000000001b5ac >> R13: 0000000000401ea0 R14: 0000000000000000 R15: 0000000000000000 >> >> Allocated by task 9723: >> save_stack+0x43/0xd0 mm/kasan/kasan.c:448 >> set_track mm/kasan/kasan.c:460 [inline] >> kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 >> __do_kmalloc_node mm/slab.c:3682 [inline] >> __kmalloc_node+0x47/0x70 mm/slab.c:3689 >> kmalloc_node include/linux/slab.h:554 [inline] >> bpf_map_area_alloc+0x3f/0x90 kernel/bpf/syscall.c:144 >> sock_map_alloc+0x376/0x410 kernel/bpf/sockmap.c:1555 >> find_and_alloc_map kernel/bpf/syscall.c:126 [inline] >> map_create+0x393/0x1010 kernel/bpf/syscall.c:448 >> __do_sys_bpf kernel/bpf/syscall.c:2128 [inline] >> __se_sys_bpf kernel/bpf/syscall.c:2105 [inline] >> __x64_sys_bpf+0x300/0x4f0 kernel/bpf/syscall.c:2105 >> do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> >> Freed by task 4521: >> save_stack+0x43/0xd0 mm/kasan/kasan.c:448 >> set_track mm/kasan/kasan.c:460 [inline] >> __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 >> kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 >> __cache_free mm/slab.c:3498 [inline] >> kfree+0xd9/0x260 mm/slab.c:3813 >> kvfree+0x61/0x70 mm/util.c:440 >> bpf_map_area_free+0x15/0x20 kernel/bpf/syscall.c:155 >> sock_map_remove_complete kernel/bpf/sockmap.c:1443 [inline] >> sock_map_free+0x408/0x540 kernel/bpf/sockmap.c:1619 >> bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:259 >> process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 >> worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 >> kthread+0x345/0x410 kernel/kthread.c:238 >> ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 >> >> The buggy address belongs to the object at ffff8801ca277680 >> which belongs to the cache kmalloc-1024 of size 1024 >> The buggy address is located 0 bytes inside of >> 1024-byte region [ffff8801ca277680, ffff8801ca277a80) >> The buggy address belongs to the page: >> page:ffffea0007289d80 count:1 mapcount:0 mapping:ffff8801ca276000 index:0x0 compound_mapcount: 0 >> flags: 0x2fffc0000008100(slab|head) >> raw: 02fffc0000008100 ffff8801ca276000 0000000000000000 0000000100000007 >> raw: ffffea0006d12b20 ffffea000763bba0 ffff8801da800ac0 0000000000000000 >> page dumped because: kasan: bad access detected >> >> Memory state around the buggy address: >> ffff8801ca277580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff8801ca277600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>> ffff8801ca277680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ^ >> ffff8801ca277700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ffff8801ca277780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ================================================================== >> >> >> --- >> This bug is generated by a bot. It may contain errors. >> See https://goo.gl/tpsmEJ for more information about syzbot. >> syzbot engineers can be reached at syzkaller@googlegroups.com. >> >> syzbot will keep track of this bug report. See: >> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. >> syzbot can test patches for this bug, for details see: >> https://goo.gl/tpsmEJ#testing-patches > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/ca3eff64-adb0-6110-38ca-2e07b6ecc3d6%40iogearbox.net. > For more options, visit https://groups.google.com/d/optout.
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