Commit bf8acc9e authored by Hyunchul Lee's avatar Hyunchul Lee Committed by Steve French
Browse files

ksmbd: improve credits management 



* Requests except READ, WRITE, IOCTL, INFO, QUERY
DIRECOTRY, CANCEL must consume one credit.
* If client's granted credits are insufficient,
refuse to handle requests.
* Windows server 2016 or later grant up to 8192
credits to clients at once.

Acked-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
Signed-off-by: default avatarHyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent f7db8fd0

fs/ksmbd/connection.c

+2 −0
Original line number Diff line number Diff line
@@ -61,6 +61,8 @@ struct ksmbd_conn *ksmbd_conn_alloc(void) 
		conn->local_nls = load_nls_default();

	atomic_set(&conn->req_running, 0);

	atomic_set(&conn->r_count, 0);

	conn->total_credits = 1;



	init_waitqueue_head(&conn->req_running_q);

	INIT_LIST_HEAD(&conn->conns_list);

	INIT_LIST_HEAD(&conn->sessions);

fs/ksmbd/smb2misc.c

+28 −10
Original line number Diff line number Diff line
@@ -284,11 +284,13 @@ static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h) 
		le32_to_cpu(h->MaxOutputResponse);

}



static int smb2_validate_credit_charge(struct smb2_hdr *hdr)

static int smb2_validate_credit_charge(struct ksmbd_conn *conn,

				       struct smb2_hdr *hdr)

{

	int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;

	int credit_charge = le16_to_cpu(hdr->CreditCharge);

	unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;

	unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge);

	void *__hdr = hdr;

	int ret;



	switch (hdr->Command) {

	case SMB2_QUERY_INFO:
@@ -310,21 +312,37 @@ static int smb2_validate_credit_charge(struct smb2_hdr *hdr) 
		req_len = smb2_ioctl_req_len(__hdr);

		expect_resp_len = smb2_ioctl_resp_len(__hdr);

		break;

	default:

	case SMB2_CANCEL:

		return 0;

	default:

		req_len = 1;

		break;

	}



	credit_charge = max(1, credit_charge);

	max_len = max(req_len, expect_resp_len);

	credit_charge = max_t(unsigned short, credit_charge, 1);

	max_len = max_t(unsigned int, req_len, expect_resp_len);

	calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE);



	if (credit_charge < calc_credit_num) {

		pr_err("Insufficient credit charge, given: %d, needed: %d\n",

		ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n",

			    credit_charge, calc_credit_num);

		return 1;

	} else if (credit_charge > conn->max_credits) {

		ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge);

		return 1;

	}



	return 0;

	spin_lock(&conn->credits_lock);

	if (credit_charge <= conn->total_credits) {

		conn->total_credits -= credit_charge;

		ret = 0;

	} else {

		ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n",

			    credit_charge, conn->total_credits);

		ret = 1;

	}

	spin_unlock(&conn->credits_lock);

	return ret;

}



int ksmbd_smb2_check_message(struct ksmbd_work *work)
@@ -383,7 +401,7 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work) 
	}



	if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&

	    smb2_validate_credit_charge(hdr)) {

	    smb2_validate_credit_charge(work->conn, hdr)) {

		work->conn->ops->set_rsp_status(work, STATUS_INVALID_PARAMETER);

		return 1;

	}

fs/ksmbd/smb2pdu.c

+29 −52
Original line number Diff line number Diff line
@@ -292,22 +292,6 @@ int init_smb2_neg_rsp(struct ksmbd_work *work) 
	return 0;

}



static int smb2_consume_credit_charge(struct ksmbd_work *work,

				      unsigned short credit_charge)

{

	struct ksmbd_conn *conn = work->conn;

	unsigned int rsp_credits = 1;



	if (!conn->total_credits)

		return 0;



	if (credit_charge > 0)

		rsp_credits = credit_charge;



	conn->total_credits -= rsp_credits;

	return rsp_credits;

}



/**

 * smb2_set_rsp_credits() - set number of credits in response buffer

 * @work:	smb work containing smb response buffer
@@ -317,49 +301,43 @@ int smb2_set_rsp_credits(struct ksmbd_work *work) 
	struct smb2_hdr *req_hdr = ksmbd_req_buf_next(work);

	struct smb2_hdr *hdr = ksmbd_resp_buf_next(work);

	struct ksmbd_conn *conn = work->conn;

	unsigned short credits_requested = le16_to_cpu(req_hdr->CreditRequest);

	unsigned short credit_charge = 1, credits_granted = 0;

	unsigned short aux_max, aux_credits, min_credits;

	int rsp_credit_charge;

	unsigned short credits_requested;

	unsigned short credit_charge, credits_granted = 0;

	unsigned short aux_max, aux_credits;



	if (hdr->Command == SMB2_CANCEL)

		goto out;

	if (work->send_no_response)

		return 0;



	/* get default minimum credits by shifting maximum credits by 4 */

	min_credits = conn->max_credits >> 4;

	hdr->CreditCharge = req_hdr->CreditCharge;



	if (conn->total_credits >= conn->max_credits) {

	if (conn->total_credits > conn->max_credits) {

		hdr->CreditRequest = 0;

		pr_err("Total credits overflow: %d\n", conn->total_credits);

		conn->total_credits = min_credits;

	}



	rsp_credit_charge =

		smb2_consume_credit_charge(work, le16_to_cpu(req_hdr->CreditCharge));

	if (rsp_credit_charge < 0)

		return -EINVAL;

	}



	hdr->CreditCharge = cpu_to_le16(rsp_credit_charge);

	credit_charge = max_t(unsigned short,

			      le16_to_cpu(req_hdr->CreditCharge), 1);

	credits_requested = max_t(unsigned short,

				  le16_to_cpu(req_hdr->CreditRequest), 1);



	if (credits_requested > 0) {

	/* according to smb2.credits smbtorture, Windows server

	 * 2016 or later grant up to 8192 credits at once.

	 *

	 * TODO: Need to adjuct CreditRequest value according to

	 * current cpu load

	 */

	aux_credits = credits_requested - 1;

		aux_max = 32;

	if (hdr->Command == SMB2_NEGOTIATE)

		aux_max = 0;

		aux_credits = (aux_credits < aux_max) ? aux_credits : aux_max;

		credits_granted = aux_credits + credit_charge;

	else

		aux_max = conn->max_credits - credit_charge;

	aux_credits = min_t(unsigned short, aux_credits, aux_max);

	credits_granted = credit_charge + aux_credits;



		/* if credits granted per client is getting bigger than default

		 * minimum credits then we should wrap it up within the limits.

		 */

		if ((conn->total_credits + credits_granted) > min_credits)

			credits_granted = min_credits -	conn->total_credits;

		/*

		 * TODO: Need to adjuct CreditRequest value according to

		 * current cpu load

		 */

	} else if (conn->total_credits == 0) {

		credits_granted = 1;

	}

	if (conn->max_credits - conn->total_credits < credits_granted)

		credits_granted = conn->max_credits -

			conn->total_credits;



	conn->total_credits += credits_granted;

	work->credits_granted += credits_granted;
@@ -368,7 +346,6 @@ int smb2_set_rsp_credits(struct ksmbd_work *work) 
		/* Update CreditRequest in last request */

		hdr->CreditRequest = cpu_to_le16(work->credits_granted);

	}

out:

	ksmbd_debug(SMB,

		    "credits: requested[%d] granted[%d] total_granted[%d]\n",

		    credits_requested, credits_granted,