From 97e05463e0dfa8df709009625302fa5c5049b016 Mon Sep 17 00:00:00 2001 From: Milan Broz Date: Wed, 9 Aug 2017 17:47:26 +0200 Subject: [PATCH] bio-integrity: Fix regression if profile verify_fn is NULL 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 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: Milan Broz [hch: trivial whitespace fix] Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/bio-integrity.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/block/bio-integrity.c b/block/bio-integrity.c index fc71e6172869..553d75e357b4 100644 --- a/block/bio-integrity.c +++ b/block/bio-integrity.c @@ -385,7 +385,10 @@ 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 = blk_get_integrity(bio->bi_disk); + + if (bio_op(bio) == REQ_OP_READ && !bio->bi_status && + bi->profile->verify_fn) { struct bio_integrity_payload *bip = bio_integrity(bio); INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);