[PATCH 5.4 358/389] scsi: lpfc: Prevent buffer overflow crashes in debugfs with malformed user input

[Greg Kroah-Hartman]

From: James Smart <jsmart2021@xxxxxxxxx>

[ Upstream commit f8191d40aa612981ce897e66cda6a88db8df17bb ]

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/20220701211425.2708-3-jsmart2021@xxxxxxxxx
Co-developed-by: Justin Tee <justin.tee@xxxxxxxxxxxx>
Signed-off-by: Justin Tee <justin.tee@xxxxxxxxxxxx>
Signed-off-by: James Smart <jsmart2021@xxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/lpfc/lpfc_debugfs.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_debugfs.c b/drivers/scsi/lpfc/lpfc_debugfs.c
index e15bb3dfe995..69551132f304 100644
--- a/drivers/scsi/lpfc/lpfc_debugfs.c
+++ b/drivers/scsi/lpfc/lpfc_debugfs.c
@@ -2402,8 +2402,8 @@ 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;
 
 	/* Protect copy from user */
 	if (!access_ok(buf, nbytes))
@@ -2487,8 +2487,8 @@ 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));
 
@@ -2629,8 +2629,8 @@ lpfc_debugfs_nvmektime_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));
 
@@ -2757,8 +2757,8 @@ 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));
 
@@ -2863,8 +2863,8 @@ lpfc_debugfs_cpucheck_write(struct file *file, const char __user *buf,
 	char *pbuf;
 	int i, j;
 
-	if (nbytes > 64)
-		nbytes = 64;
+	if (nbytes > sizeof(mybuf) - 1)
+		nbytes = sizeof(mybuf) - 1;
 
 	memset(mybuf, 0, sizeof(mybuf));
 
-- 
2.35.1