nvmet-auth: expire authentication sessions

Each authentication step is required to be completed within the
KATO interval (or two minutes if not set). So add a workqueue function
to reset the transaction ID and the expected next protocol step;
this will automatically the next authentication command referring
to the terminated authentication.

Signed-off-by: Hannes Reinecke <[e-mail]>
Reviewed-by: Sagi Grimberg <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

drivers/nvme/target/auth.c

···
 
 void nvmet_auth_sq_free(struct nvmet_sq *sq)
 {
+	cancel_delayed_work(&sq->auth_expired_work);
 	kfree(sq->dhchap_c1);
 	sq->dhchap_c1 = NULL;
 	kfree(sq->dhchap_c2);

drivers/nvme/target/fabrics-cmd-auth.c

···
 #include <crypto/kpp.h>
 #include "nvmet.h"
 
+static void nvmet_auth_expired_work(struct work_struct *work)
+{
+	struct nvmet_sq *sq = container_of(to_delayed_work(work),
+			struct nvmet_sq, auth_expired_work);
+
+	pr_debug("%s: ctrl %d qid %d transaction %u expired, resetting\n",
+		 __func__, sq->ctrl->cntlid, sq->qid, sq->dhchap_tid);
+	sq->dhchap_step = NVME_AUTH_DHCHAP_MESSAGE_NEGOTIATE;
+	sq->dhchap_tid = -1;
+}
+
 void nvmet_init_auth(struct nvmet_ctrl *ctrl, struct nvmet_req *req)
 {
 	u32 result = le32_to_cpu(req->cqe->result.u32);
 
 	/* Initialize in-band authentication */
+	INIT_DELAYED_WORK(&req->sq->auth_expired_work,
+			  nvmet_auth_expired_work);
 	req->sq->authenticated = false;
 	req->sq->dhchap_step = NVME_AUTH_DHCHAP_MESSAGE_NEGOTIATE;
 	result |= (u32)NVME_CONNECT_AUTHREQ_ATR << 16;
···
 	req->cqe->result.u64 = 0;
 	nvmet_req_complete(req, status);
 	if (req->sq->dhchap_step != NVME_AUTH_DHCHAP_MESSAGE_SUCCESS2 &&
-	    req->sq->dhchap_step != NVME_AUTH_DHCHAP_MESSAGE_FAILURE2)
+	    req->sq->dhchap_step != NVME_AUTH_DHCHAP_MESSAGE_FAILURE2) {
+		unsigned long auth_expire_secs = ctrl->kato ? ctrl->kato : 120;
+
+		mod_delayed_work(system_wq, &req->sq->auth_expired_work,
+				 auth_expire_secs * HZ);
 		return;
+	}
 	/* Final states, clear up variables */
 	nvmet_auth_sq_free(req->sq);
 	if (req->sq->dhchap_step == NVME_AUTH_DHCHAP_MESSAGE_FAILURE2)

drivers/nvme/target/nvmet.h

···
 	u32			sqhd;
 	bool			sqhd_disabled;
 #ifdef CONFIG_NVME_TARGET_AUTH
+	struct delayed_work	auth_expired_work;
 	bool			authenticated;
 	u16			dhchap_tid;
 	u16			dhchap_status;