Messages in this thread |  | | Date | Sun, 29 Apr 2018 09:31:01 -0700 | Subject | KASAN: use-after-free Read in path_init | From | syzbot <> |
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Hello,
syzbot hit the following crash on upstream commit d8a332730e757129e70675679f2b2a03f1ecf65e (Fri Apr 27 17:39:38 2018 +0000) Merge tag 'char-misc-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=ebb37fc8fd7a28c93dec
Unfortunately, I don't have any reproducer for this crash yet. Raw console output: https://syzkaller.appspot.com/x/log.txt?id=6333718402695168 Kernel config: https://syzkaller.appspot.com/x/.config?id=7043958930931867332 compiler: gcc (GCC) 8.0.1 20180413 (experimental)
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TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. ================================================================== BUG: KASAN: use-after-free in path_init+0x1675/0x2320 fs/namei.c:2132 Read of size 1 at addr ffff8801c907ae80 by task syz-executor7/4548
CPU: 1 PID: 4548 Comm: syz-executor7 Not tainted 4.17.0-rc2+ #20 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 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 path_init+0x1675/0x2320 fs/namei.c:2132 path_openat+0x1f1/0x4e20 fs/namei.c:3495 do_filp_open+0x249/0x350 fs/namei.c:3535 do_sys_open+0x56f/0x740 fs/open.c:1093 __do_sys_open fs/open.c:1111 [inline] __se_sys_open fs/open.c:1106 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1106 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x453aa0 RSP: 002b:0000000000a3d940 EFLAGS: 00000202 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000000000000004a RCX: 0000000000453aa0 RDX: 000000000000000c RSI: 0000000000090800 RDI: 0000000000a3f790 RBP: 0000000000a3f790 R08: 0000000000000001 R09: 0000000000e25940 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000001e4 R13: 0000000000000000 R14: 00000000000001e4 R15: 000000000001b450
Allocated by task 4549: 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 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554 getname_flags+0xd0/0x5a0 fs/namei.c:140 getname fs/namei.c:211 [inline] do_rmdir+0xe3/0x610 fs/namei.c:3878 __do_sys_rmdir fs/namei.c:3929 [inline] __se_sys_rmdir fs/namei.c:3927 [inline] __x64_sys_rmdir+0x36/0x40 fs/namei.c:3927 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 4549: 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] kmem_cache_free+0x86/0x2d0 mm/slab.c:3756 putname+0xf2/0x130 fs/namei.c:261 do_rmdir+0x202/0x610 fs/namei.c:3919 __do_sys_rmdir fs/namei.c:3929 [inline] __se_sys_rmdir fs/namei.c:3927 [inline] __x64_sys_rmdir+0x36/0x40 fs/namei.c:3927 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff8801c907ae80 which belongs to the cache names_cache of size 4096 The buggy address is located 0 bytes inside of 4096-byte region [ffff8801c907ae80, ffff8801c907be80) The buggy address belongs to the page: page:ffffea0007241e80 count:1 mapcount:0 mapping:ffff8801c907ae80 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffff8801c907ae80 0000000000000000 0000000100000001 raw: ffffea0007245ea0 ffffea0006bbc220 ffff8801da988dc0 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff8801c907ad80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801c907ae00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801c907ae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801c907af00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c907af80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================
--- This bug is generated by a dumb bot. It may contain errors. See https://goo.gl/tpsmEJ for details. Direct all questions to syzkaller@googlegroups.com.
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