diff options
| author | Sagi Grimberg <sagi@grimberg.me> | 2021-06-17 00:19:36 +0300 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2021-08-16 15:42:22 +0300 |
| commit | e7006de6c23803799be000a5dcce4d916a36541a (patch) | |
| tree | c8ae69e3cca3580db8680b7a9558ae07325d7860 /drivers/nvme/target | |
| parent | 3b01a9d0caa8276d9ce314e09610f7fb70f49a00 (diff) | |
| download | linux-e7006de6c23803799be000a5dcce4d916a36541a.tar.xz | |
nvme: code command_id with a genctr for use-after-free validation
We cannot detect a (perhaps buggy) controller that is sending us
a completion for a request that was already completed (for example
sending a completion twice), this phenomenon was seen in the wild
a few times.
So to protect against this, we use the upper 4 msbits of the nvme sqe
command_id to use as a 4-bit generation counter and verify it matches
the existing request generation that is incrementing on every execution.
The 16-bit command_id structure now is constructed by:
| xxxx | xxxxxxxxxxxx |
gen request tag
This means that we are giving up some possible queue depth as 12 bits
allow for a maximum queue depth of 4095 instead of 65536, however we
never create such long queues anyways so no real harm done.
Suggested-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Tested-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/nvme/target')
| -rw-r--r-- | drivers/nvme/target/loop.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c index 3a17a7e26bbf..0285ccc7541f 100644 --- a/drivers/nvme/target/loop.c +++ b/drivers/nvme/target/loop.c @@ -107,10 +107,10 @@ static void nvme_loop_queue_response(struct nvmet_req *req) } else { struct request *rq; - rq = blk_mq_tag_to_rq(nvme_loop_tagset(queue), cqe->command_id); + rq = nvme_find_rq(nvme_loop_tagset(queue), cqe->command_id); if (!rq) { dev_err(queue->ctrl->ctrl.device, - "tag 0x%x on queue %d not found\n", + "got bad command_id %#x on queue %d\n", cqe->command_id, nvme_loop_queue_idx(queue)); return; } |