1 files changed, 37 insertions, 18 deletions

diff --git a/fs/ksmbd/smb2misc.c b/fs/ksmbd/smb2misc.c
index 9edd9c161b27..030ca57c3784 100644
--- a/fs/ksmbd/smb2misc.c
+++ b/fs/ksmbd/smb2misc.c
@@ -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",
-		       credit_charge, calc_credit_num);
+		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)
@@ -382,26 +400,20 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work)
 		}
 	}
 
-	if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
-	    smb2_validate_credit_charge(hdr)) {
-		work->conn->ops->set_rsp_status(work, STATUS_INVALID_PARAMETER);
-		return 1;
-	}
-
 	if (smb2_calc_size(hdr, &clc_len))
 		return 1;
 
 	if (len != clc_len) {
 		/* client can return one byte more due to implied bcc[0] */
 		if (clc_len == len + 1)
-			return 0;
+			goto validate_credit;
 
 		/*
 		 * Some windows servers (win2016) will pad also the final
 		 * PDU in a compound to 8 bytes.
 		 */
 		if (ALIGN(clc_len, 8) == len)
-			return 0;
+			goto validate_credit;
 
 		/*
 		 * windows client also pad up to 8 bytes when compounding.
@@ -414,7 +426,7 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work)
 				    "cli req padded more than expected. Length %d not %d for cmd:%d mid:%llu\n",
 				    len, clc_len, command,
 				    le64_to_cpu(hdr->MessageId));
-			return 0;
+			goto validate_credit;
 		}
 
 		ksmbd_debug(SMB,
@@ -425,6 +437,13 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work)
 		return 1;
 	}
 
+validate_credit:
+	if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
+	    smb2_validate_credit_charge(work->conn, hdr)) {
+		work->conn->ops->set_rsp_status(work, STATUS_INVALID_PARAMETER);
+		return 1;
+	}
+
 	return 0;
 }