Re: KASAN: use-after-free Read in cma_check_port

[Leon Romanovsky]

#syz dup: WARNING in cma_exit_net

On Mon, Apr 01, 2019 at 10:35:06AM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    e3ecb83e Add linux-next specific files for 20190401
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=12e48937200000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=db6c9f2bfeb91a99
> dashboard link: https://syzkaller.appspot.com/bug?extid=70f6c187224c333bb8da
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+70f6c187224c333bb8da@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> ==================================================================
> BUG: KASAN: use-after-free in cma_check_port+0x8ce/0x8f0
> drivers/infiniband/core/cma.c:3354
> Read of size 8 at addr ffff88809a6e7a08 by task syz-executor.2/901
>
> CPU: 0 PID: 901 Comm: syz-executor.2 Not tainted 5.1.0-rc2-next-20190401 #15
> 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+0x172/0x1f0 lib/dump_stack.c:113
>  print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
>  kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
>  __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
>  cma_check_port+0x8ce/0x8f0 drivers/infiniband/core/cma.c:3354
>  cma_use_port drivers/infiniband/core/cma.c:3391 [inline]
>  cma_get_port drivers/infiniband/core/cma.c:3473 [inline]
>  rdma_bind_addr+0x19c3/0x1f80 drivers/infiniband/core/cma.c:3591
>  cma_bind_addr drivers/infiniband/core/cma.c:3121 [inline]
>  rdma_resolve_addr+0x437/0x21f0 drivers/infiniband/core/cma.c:3132
>  ucma_resolve_ip+0x153/0x210 drivers/infiniband/core/ucma.c:715
>  ucma_write+0x2da/0x3c0 drivers/infiniband/core/ucma.c:1696
>  __vfs_write+0x8d/0x110 fs/read_write.c:485
>  vfs_write+0x20c/0x580 fs/read_write.c:549
>  ksys_write+0xea/0x1f0 fs/read_write.c:598
>  __do_sys_write fs/read_write.c:610 [inline]
>  __se_sys_write fs/read_write.c:607 [inline]
>  __x64_sys_write+0x73/0xb0 fs/read_write.c:607
>  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x458209
> Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007f1cae168c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458209
> RDX: 0000000000000048 RSI: 00000000200001c0 RDI: 000000000000000b
> RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1cae1696d4
> R13: 00000000004ce0e8 R14: 00000000004dd828 R15: 00000000ffffffff
>
> Allocated by task 884:
>  save_stack+0x45/0xd0 mm/kasan/common.c:75
>  set_track mm/kasan/common.c:87 [inline]
>  __kasan_kmalloc mm/kasan/common.c:497 [inline]
>  __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
>  kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511
>  kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3622
>  kmalloc include/linux/slab.h:547 [inline]
>  kzalloc include/linux/slab.h:742 [inline]
>  cma_alloc_port+0x4f/0x1a0 drivers/infiniband/core/cma.c:3241
>  cma_use_port drivers/infiniband/core/cma.c:3389 [inline]
>  cma_get_port drivers/infiniband/core/cma.c:3473 [inline]
>  rdma_bind_addr+0x1bc0/0x1f80 drivers/infiniband/core/cma.c:3591
>  cma_bind_addr drivers/infiniband/core/cma.c:3121 [inline]
>  rdma_resolve_addr+0x437/0x21f0 drivers/infiniband/core/cma.c:3132
>  ucma_resolve_ip+0x153/0x210 drivers/infiniband/core/ucma.c:715
>  ucma_write+0x2da/0x3c0 drivers/infiniband/core/ucma.c:1696
>  __vfs_write+0x8d/0x110 fs/read_write.c:485
>  vfs_write+0x20c/0x580 fs/read_write.c:549
>  ksys_write+0xea/0x1f0 fs/read_write.c:598
>  __do_sys_write fs/read_write.c:610 [inline]
>  __se_sys_write fs/read_write.c:607 [inline]
>  __x64_sys_write+0x73/0xb0 fs/read_write.c:607
>  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Freed by task 881:
>  save_stack+0x45/0xd0 mm/kasan/common.c:75
>  set_track mm/kasan/common.c:87 [inline]
>  __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
>  kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
>  __cache_free mm/slab.c:3499 [inline]
>  kfree+0xcf/0x230 mm/slab.c:3822
>  cma_release_port drivers/infiniband/core/cma.c:1773 [inline]
>  rdma_destroy_id+0x7fc/0xaa0 drivers/infiniband/core/cma.c:1840
>  ucma_close+0x115/0x320 drivers/infiniband/core/ucma.c:1777
>  __fput+0x2e5/0x8d0 fs/file_table.c:278
>  ____fput+0x16/0x20 fs/file_table.c:309
>  task_work_run+0x14a/0x1c0 kernel/task_work.c:113
>  tracehook_notify_resume include/linux/tracehook.h:188 [inline]
>  exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
>  prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
>  syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
>  do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> The buggy address belongs to the object at ffff88809a6e7a00
>  which belongs to the cache kmalloc-32 of size 32
> The buggy address is located 8 bytes inside of
>  32-byte region [ffff88809a6e7a00, ffff88809a6e7a20)
> The buggy address belongs to the page:
> page:ffffea000269b9c0 count:1 mapcount:0 mapping:ffff88812c3f01c0
> index:0xffff88809a6e7fc1
> flags: 0x1fffc0000000200(slab)
> raw: 01fffc0000000200 ffffea0002945248 ffffea00023b0f48 ffff88812c3f01c0
> raw: ffff88809a6e7fc1 ffff88809a6e7000 0000000100000039 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffff88809a6e7900: 00 01 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
>  ffff88809a6e7980: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
> > ffff88809a6e7a00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>                       ^
>  ffff88809a6e7a80: 00 00 00 00 fc fc fc fc fb fb fb fb fc fc fc fc
>  ffff88809a6e7b00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
> ==================================================================
>
>
> ---
> 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@xxxxxxxxxxxxxxxxx
>
> syzbot will keep track of this bug report. See:
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