Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) client-ip=23.128.96.35;
From:   Mark O'Donovan <shiftee@posteo.net>
To:     linux-kernel@vger.kernel.org
Cc:     linux-nvme@lists.infradead.org, sagi@grimberg.me, hch@lst.de,
        axboe@kernel.dk, kbusch@kernel.org, hare@suse.de,
        Mark O'Donovan <shiftee@posteo.net>
Subject: [PATCH v2 3/3] nvme-auth: always set valid seq_num in dhchap reply
Date:   Mon, 23 Oct 2023 14:00:03 +0000
Message-Id: <20231023140003.58019-4-shiftee@posteo.net>
In-Reply-To: <20231023140003.58019-1-shiftee@posteo.net>
References: <20231023140003.58019-1-shiftee@posteo.net>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Currently a seqnum of zero is sent during uni-directional
authentication. The zero value is reserved for the secure channel
feature which is not yet implemented.

Relevant extract from the spec:
The value 0h is used to indicate that bidirectional authentication
is not performed, but a challenge value C2 is carried in order to
generate a pre-shared key (PSK) for subsequent establishment of a
secure channel

Signed-off-by: Mark O'Donovan <shiftee@posteo.net>

---
v1: used incorrect prefix nvme-tcp
v2: added spec extract to commit message

 drivers/nvme/host/auth.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index 8558a02865ac..7f6b2e99a78c 100644
--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -316,15 +316,14 @@ static int nvme_auth_set_dhchap_reply_data(struct nvme_ctrl *ctrl,
 		chap->bi_directional = true;
 		get_random_bytes(chap->c2, chap->hash_len);
 		data->cvalid = 1;
-		chap->s2 = nvme_auth_get_seqnum();
 		memcpy(data->rval + chap->hash_len, chap->c2,
 		       chap->hash_len);
 		dev_dbg(ctrl->device, "%s: qid %d ctrl challenge %*ph\n",
 			__func__, chap->qid, (int)chap->hash_len, chap->c2);
 	} else {
 		memset(chap->c2, 0, chap->hash_len);
-		chap->s2 = 0;
 	}
+	chap->s2 = nvme_auth_get_seqnum();
 	data->seqnum = cpu_to_le32(chap->s2);
 	if (chap->host_key_len) {
 		dev_dbg(ctrl->device, "%s: qid %d host public key %*ph\n",
-- 
2.39.2