scsi: lpfc: Prevent buffer overflow crashes in debugfs with malformed…

… user input

Malformed user input to debugfs results in buffer overflow crashes.  Adapt
input string lengths to fit within internal buffers, leaving space for NULL
terminators.

Link: https://lore.kernel.org/r/[email protected]
Co-developed-by: Justin Tee <[email protected]>
Signed-off-by: Justin Tee <[email protected]>
Signed-off-by: James Smart <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

drivers/scsi/lpfc/lpfc_debugfs.c

@@ -2607,8 +2607,8 @@ lpfc_debugfs_multixripools_write(struct file *file, const char __user *buf,
 	struct lpfc_sli4_hdw_queue *qp;
 	struct lpfc_multixri_pool *multixri_pool;
 
-	if (nbytes > 64)
-		nbytes = 64;
+	if (nbytes > sizeof(mybuf) - 1)
+		nbytes = sizeof(mybuf) - 1;
 
 	memset(mybuf, 0, sizeof(mybuf));
 
@@ -2688,8 +2688,8 @@ lpfc_debugfs_nvmestat_write(struct file *file, const char __user *buf,
 	if (!phba->targetport)
 		return -ENXIO;
 
-	if (nbytes > 64)
-		nbytes = 64;
+	if (nbytes > sizeof(mybuf) - 1)
+		nbytes = sizeof(mybuf) - 1;
 
 	memset(mybuf, 0, sizeof(mybuf));
 
@@ -2826,8 +2826,8 @@ lpfc_debugfs_ioktime_write(struct file *file, const char __user *buf,
 	char mybuf[64];
 	char *pbuf;
 
-	if (nbytes > 64)
-		nbytes = 64;
+	if (nbytes > sizeof(mybuf) - 1)
+		nbytes = sizeof(mybuf) - 1;
 
 	memset(mybuf, 0, sizeof(mybuf));
 
@@ -2954,8 +2954,8 @@ lpfc_debugfs_nvmeio_trc_write(struct file *file, const char __user *buf,
 	char mybuf[64];
 	char *pbuf;
 
-	if (nbytes > 63)
-		nbytes = 63;
+	if (nbytes > sizeof(mybuf) - 1)
+		nbytes = sizeof(mybuf) - 1;
 
 	memset(mybuf, 0, sizeof(mybuf));
 
@@ -3060,8 +3060,8 @@ lpfc_debugfs_hdwqstat_write(struct file *file, const char __user *buf,
 	char *pbuf;
 	int i;
 
-	if (nbytes > 64)
-		nbytes = 64;
+	if (nbytes > sizeof(mybuf) - 1)
+		nbytes = sizeof(mybuf) - 1;
 
 	memset(mybuf, 0, sizeof(mybuf));