syzbot


KASAN: use-after-free Read in cma_cancel_operation

Status: fixed on 2020/05/01 08:27
Reported-by: syzbot+74ab2079df15699ca121@syzkaller.appspotmail.com
Fix commit: abc4ea7f1345 RDMA/ucma: Put a lock around every call to the rdma_cm layer
First crash: 1056d, last: 906d

Fix bisection: fixed by (bisect log) :
commit abc4ea7f1345398261295345fd9b30243e4f4f8e
Author: Jason Gunthorpe <jgg@mellanox.com>
Date: Tue Feb 18 19:45:38 2020 +0000

  RDMA/ucma: Put a lock around every call to the rdma_cm layer

similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in cma_cancel_operation C done 617 955d 1635d 17/24 fixed on 2020/05/10 10:42
linux-4.14 KASAN: use-after-free Read in cma_cancel_operation C inconclusive 49 1d04h 1009d 0/1 upstream: reported C repro on 2019/12/19 22:41

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54
Read of size 8 at addr ffff8880953face8 by task syz-executor188/30263

CPU: 1 PID: 30263 Comm: syz-executor188 Not tainted 4.19.100-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+0x197/0x210 lib/dump_stack.c:118
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54
 __list_del_entry include/linux/list.h:117 [inline]
 list_del include/linux/list.h:125 [inline]
 cma_cancel_listens drivers/infiniband/core/cma.c:1625 [inline]
 cma_cancel_operation drivers/infiniband/core/cma.c:1653 [inline]
 cma_cancel_operation+0x2d7/0xa10 drivers/infiniband/core/cma.c:1641
 rdma_destroy_id+0x8d/0xab0 drivers/infiniband/core/cma.c:1717
 ucma_close+0x115/0x320 drivers/infiniband/core/ucma.c:1770
 __fput+0x2dd/0x8b0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x53d/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x408881
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 24 1a 00 00 c3 48 83 ec 08 e8 6a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 b3 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007fff31e86cd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000408881
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000006e59ec R08: 0000000000000000 R09: 0000000000000000
R10: 00007fff31e86d00 R11: 0000000000000293 R12: 00000000006e59e0
R13: 0000000000000000 R14: 000000000000002d R15: 20c49ba5e353f7cf

Allocated by task 30267:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc mm/kasan/kasan.c:553 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531
 kmem_cache_alloc_trace+0x152/0x760 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 __rdma_create_id+0x5e/0x610 drivers/infiniband/core/cma.c:784
 ucma_create_id+0x1de/0x640 drivers/infiniband/core/ucma.c:506
 ucma_write+0x2d7/0x3c0 drivers/infiniband/core/ucma.c:1689
 __vfs_write+0x114/0x810 fs/read_write.c:485
 vfs_write+0x20c/0x560 fs/read_write.c:549
 ksys_write+0x14f/0x2d0 fs/read_write.c:599
 __do_sys_write fs/read_write.c:611 [inline]
 __se_sys_write fs/read_write.c:608 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:608
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 30262:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcf/0x220 mm/slab.c:3822
 rdma_destroy_id+0x726/0xab0 drivers/infiniband/core/cma.c:1752
 ucma_close+0x115/0x320 drivers/infiniband/core/ucma.c:1770
 __fput+0x2dd/0x8b0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x53d/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880953fab00
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 488 bytes inside of
 2048-byte region [ffff8880953fab00, ffff8880953fb300)
The buggy address belongs to the page:
page:ffffea000254fe80 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0xffff8880953fa280 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea0002924f88 ffffea0002536188 ffff88812c31cc40
raw: ffff8880953fa280 ffff8880953fa280 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880953fab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880953fac00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880953fac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff8880953fad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880953fad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (6):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2020/01/31 20:57 linux-4.19.y 7cdefde351b6 0eb59c27 .config log report syz C
ci2-linux-4-19 2020/04/01 04:31 linux-4.19.y 54b4fa6d3955 a34e2c33 .config log report
ci2-linux-4-19 2020/03/28 18:00 linux-4.19.y 54b4fa6d3955 f1ebdfba .config log report
ci2-linux-4-19 2020/01/31 19:12 linux-4.19.y 7cdefde351b6 0eb59c27 .config log report
ci2-linux-4-19 2019/11/12 12:31 linux-4.19.y 7d8dbefc22ff 048f2d49 .config log report
ci2-linux-4-19 2019/11/02 17:19 linux-4.19.y ef244c308885 997ccc67 .config log report
* Struck through repros no longer work on HEAD.