From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Date: Mon, 6 Mar 2023 01:13:13 +0000 (+0900)
Subject: nvmet: avoid potential UAF in nvmet_req_complete()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f1d5888a5efe345b63c430b256e95acb0a475642;p=linux.git

nvmet: avoid potential UAF in nvmet_req_complete()

[ Upstream commit 6173a77b7e9d3e202bdb9897b23f2a8afe7bf286 ]

An nvme target ->queue_response() operation implementation may free the
request passed as argument. Such implementation potentially could result
in a use after free of the request pointer when percpu_ref_put() is
called in nvmet_req_complete().

Avoid such problem by using a local variable to save the sq pointer
before calling __nvmet_req_complete(), thus avoiding dereferencing the
req pointer after that function call.

Fixes: a07b4970f464 ("nvmet: add a generic NVMe target")
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index cfd0385511564..4c6d56dd29adc 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -756,8 +756,10 @@ static void __nvmet_req_complete(struct nvmet_req *req, u16 status)
 
 void nvmet_req_complete(struct nvmet_req *req, u16 status)
 {
+	struct nvmet_sq *sq = req->sq;
+
 	__nvmet_req_complete(req, status);
-	percpu_ref_put(&req->sq->ref);
+	percpu_ref_put(&sq->ref);
 }
 EXPORT_SYMBOL_GPL(nvmet_req_complete);