[PATCH 5.12 687/700] scsi: libfc: Correct the condition check and invalid argument passed

[Greg Kroah-Hartman]

From: Javed Hasan <jhasan@xxxxxxxxxxx>

commit 8f70328c068f9f5c5db82848724cb276f657b9cd upstream.

Incorrect condition check was leading to data corruption.

Link: https://lore.kernel.org/r/20210603101404.7841-3-jhasan@xxxxxxxxxxx
Fixes: 8fd9efca86d0 ("scsi: libfc: Work around -Warray-bounds warning")
CC: stable@xxxxxxxxxxxxxxx
Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
Signed-off-by: Javed Hasan <jhasan@xxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/scsi/libfc/fc_encode.h |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/scsi/libfc/fc_encode.h
+++ b/drivers/scsi/libfc/fc_encode.h
@@ -166,9 +166,11 @@ static inline int fc_ct_ns_fill(struct f
 static inline void fc_ct_ms_fill_attr(struct fc_fdmi_attr_entry *entry,
 				    const char *in, size_t len)
 {
-	int copied = strscpy(entry->value, in, len);
-	if (copied > 0)
-		memset(entry->value, copied, len - copied);
+	int copied;
+
+	copied = strscpy((char *)&entry->value, in, len);
+	if (copied > 0 && (copied + 1) < len)
+		memset((entry->value + copied + 1), 0, len - copied - 1);
 }
 
 /**