Subject: Re: [PATCH 10/12] nvmet: Implement basic In-Band Authentication
To:     Sagi Grimberg <sagi@grimberg.me>
Cc:     Christoph Hellwig <hch@lst.de>, Keith Busch <keith.busch@wdc.com>,
        linux-nvme@lists.infradead.org,
        Herbert Xu <herberg@gondor.apana.org.au>,
        David Miller <davem@davemloft.org>,
        linux-crypto@vger.kernel.org
References: <20211122074727.25988-1-hare@suse.de>
 <20211122074727.25988-11-hare@suse.de>
 <762ce404-9035-30ca-078d-eb0b36223e4c@grimberg.me>
 <313b19d2-ea54-ce1c-f9cb-3f1fb6743787@suse.de>
 <891fe077-40d3-5bad-52fb-f0ee6f6107b6@grimberg.me>
From:   Hannes Reinecke <hare@suse.de>
Organization: SUSE Linux GmbH
Message-ID: <f7011868-4542-bd09-6d44-3aaa192a9212@suse.de>
Date:   Mon, 22 Nov 2021 15:17:59 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.12.0
MIME-Version: 1.0
In-Reply-To: <891fe077-40d3-5bad-52fb-f0ee6f6107b6@grimberg.me>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 11/22/21 3:00 PM, Sagi Grimberg wrote:
> 
> 
> On 11/22/21 3:21 PM, Hannes Reinecke wrote:
>> On 11/22/21 12:59 PM, Sagi Grimberg wrote:
>>>
>>>> +void nvmet_execute_auth_send(struct nvmet_req *req)
>>>> +{
>>>> +    struct nvmet_ctrl *ctrl = req->sq->ctrl;
>>>> +    struct nvmf_auth_dhchap_success2_data *data;
>>>> +    void *d;
>>>> +    u32 tl;
>>>> +    u16 status = 0;
>>>> +
>>>> +    if (req->cmd->auth_send.secp !=
>>>> NVME_AUTH_DHCHAP_PROTOCOL_IDENTIFIER) {
>>>> +        status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
>>>> +        req->error_loc =
>>>> +            offsetof(struct nvmf_auth_send_command, secp);
>>>> +        goto done;
>>>> +    }
>>>> +    if (req->cmd->auth_send.spsp0 != 0x01) {
>>>> +        status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
>>>> +        req->error_loc =
>>>> +            offsetof(struct nvmf_auth_send_command, spsp0);
>>>> +        goto done;
>>>> +    }
>>>> +    if (req->cmd->auth_send.spsp1 != 0x01) {
>>>> +        status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
>>>> +        req->error_loc =
>>>> +            offsetof(struct nvmf_auth_send_command, spsp1);
>>>> +        goto done;
>>>> +    }
>>>> +    tl = le32_to_cpu(req->cmd->auth_send.tl);
>>>> +    if (!tl) {
>>>> +        status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
>>>> +        req->error_loc =
>>>> +            offsetof(struct nvmf_auth_send_command, tl);
>>>> +        goto done;
>>>> +    }
>>>> +    if (!nvmet_check_transfer_len(req, tl)) {
>>>> +        pr_debug("%s: transfer length mismatch (%u)\n", __func__, tl);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    d = kmalloc(tl, GFP_KERNEL);
>>>> +    if (!d) {
>>>> +        status = NVME_SC_INTERNAL;
>>>> +        goto done;
>>>> +    }
>>>> +
>>>> +    status = nvmet_copy_from_sgl(req, 0, d, tl);
>>>> +    if (status) {
>>>> +        kfree(d);
>>>> +        goto done;
>>>> +    }
>>>> +
>>>> +    data = d;
>>>> +    pr_debug("%s: ctrl %d qid %d type %d id %d step %x\n", __func__,
>>>> +         ctrl->cntlid, req->sq->qid, data->auth_type, data->auth_id,
>>>> +         req->sq->dhchap_step);
>>>> +    if (data->auth_type != NVME_AUTH_COMMON_MESSAGES &&
>>>> +        data->auth_type != NVME_AUTH_DHCHAP_MESSAGES)
>>>> +        goto done_failure1;
>>>> +    if (data->auth_type == NVME_AUTH_COMMON_MESSAGES) {
>>>> +        if (data->auth_id == NVME_AUTH_DHCHAP_MESSAGE_NEGOTIATE) {
>>>> +            /* Restart negotiation */
>>>> +            pr_debug("%s: ctrl %d qid %d reset negotiation\n",
>>>> __func__,
>>>> +                 ctrl->cntlid, req->sq->qid);
>>>> +            if (!req->sq->qid) {
>>>> +                status = nvmet_setup_auth(ctrl);
>>>
>>> Aren't you leaking memory here?
>>
>> I've checked, and I _think_ everything is in order.
>> Any particular concerns?
>> ( 'd' is free at 'done_kfree', and we never exit without going through
>> it AFAICS).
>> Have I missed something?
> 
> You are calling nvmet_setup_auth for re-authentication, who is calling
> nvmet_destroy_auth to free the controller auth stuff?
> 
> Don't you need something like:
> -- 
>         if (!req->sq->qid) {
>             nvmet_destroy_auth(ctrl);
>             status = nvmet_setup_auth(ctrl);
>             ...
>         }
> -- 

nvme_setup_auth() should be re-entrant, ie it'll free old and reallocate
new keys as required. Hence no need to call nvmet_destroy_auth().
At least that's the plan.
Always possible that I messed up things somewhere.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		        Kernel Storage Architect
hare@suse.de			               +49 911 74053 688
SUSE Software Solutions Germany GmbH, 90409 Nürnberg
GF: F. Imendörffer, HRB 36809 (AG Nürnberg)