• Milan Broz's avatar
    bio-integrity: Fix regression if profile verify_fn is NULL · c775d209
    Milan Broz authored
    In dm-integrity target we register integrity profile that have
    both generate_fn and verify_fn callbacks set to NULL.
    
    This is used if dm-integrity is stacked under a dm-crypt device
    for authenticated encryption (integrity payload contains authentication
    tag and IV seed).
    
    In this case the verification is done through own crypto API
    processing inside dm-crypt; integrity profile is only holder
    of these data. (And memory is owned by dm-crypt as well.)
    
    After the commit (and previous changes)
      Commit 7c20f116
      Author: Christoph Hellwig <hch@lst.de>
      Date:   Mon Jul 3 16:58:43 2017 -0600
    
        bio-integrity: stop abusing bi_end_io
    
    we get this crash:
    
    : BUG: unable to handle kernel NULL pointer dereference at   (null)
    : IP:   (null)
    : *pde = 00000000
    ...
    :
    : Workqueue: kintegrityd bio_integrity_verify_fn
    : task: f48ae180 task.stack: f4b5c000
    : EIP:   (null)
    : EFLAGS: 00210286 CPU: 0
    : EAX: f4b5debc EBX: 00001000 ECX: 00000001 EDX: 00000000
    : ESI: 00001000 EDI: ed25f000 EBP: f4b5dee8 ESP: f4b5dea4
    :  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
    : CR0: 80050033 CR2: 00000000 CR3: 32823000 CR4: 001406d0
    : Call Trace:
    :  ? bio_integrity_process+0xe3/0x1e0
    :  bio_integrity_verify_fn+0xea/0x150
    :  process_one_work+0x1c7/0x5c0
    :  worker_thread+0x39/0x380
    :  kthread+0xd6/0x110
    :  ? process_one_work+0x5c0/0x5c0
    :  ? kthread_worker_fn+0x100/0x100
    :  ? kthread_worker_fn+0x100/0x100
    :  ret_from_fork+0x19/0x24
    : Code:  Bad EIP value.
    : EIP:   (null) SS:ESP: 0068:f4b5dea4
    : CR2: 0000000000000000
    
    Patch just skip the whole verify workqueue if verify_fn is set to NULL.
    
    Fixes: 7c20f116 ("bio-integrity: stop abusing bi_end_io")
    Signed-off-by: default avatarMilan Broz <gmazyland@gmail.com>
    [hch: trivial whitespace fix]
    Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
    Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
    c775d209
bio-integrity.c 13.9 KB