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 7c20f11680a441df09de7235206f70115fbf6290
Author: Christoph Hellwig <hch@xxxxxx>
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.
Signed-off-by: Milan Broz <gmazyland@xxxxxxxxx>
---
block/bio-integrity.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 83e92beb3c9f..b9d1580bfc13 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -387,7 +387,9 @@ static void bio_integrity_verify_fn(struct work_struct *work)
*/
bool __bio_integrity_endio(struct bio *bio)
{
- if (bio_op(bio) == REQ_OP_READ && !bio->bi_status) {
+ struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+
+ if (bi->profile->verify_fn && bio_op(bio) == REQ_OP_READ && !bio->bi_status) {
struct bio_integrity_payload *bip = bio_integrity(bio);
INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
--
2.13.3
--
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