nvmet: avoid potential UAF in nvmet_req_complete()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: nvmet: avoid potential UAF in nvmet_req_complete() 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.

References

• https://git.kernel.org/stable/c/e5d99b29012bbf0e86929403209723b2806500c1
• https://git.kernel.org/stable/c/fafcb4b26393870c45462f9af6a48e581dbbcf7e
• https://git.kernel.org/stable/c/04c394208831d5e0d5cfee46722eb0f033cd4083
• https://git.kernel.org/stable/c/a6317235da8aa7cb97529ebc8121cc2a4c4c437a
• https://git.kernel.org/stable/c/f1d5888a5efe345b63c430b256e95acb0a475642
• https://git.kernel.org/stable/c/bcd535f07c58342302a2cd2bdd8894fe0872c8a9
• https://git.kernel.org/stable/c/8ed9813871038b25a934b21ab76b5b7dbf44fc3a
• https://git.kernel.org/stable/c/6173a77b7e9d3e202bdb9897b23f2a8afe7bf286