scsi: qedf: Ensure the copied buf is NUL terminated

JIRA: https://issues.redhat.com/browse/RHEL-44202
JIRA: https://issues.redhat.com/browse/RHEL-44201
CVE: CVE-2024-38559

Currently, we allocate a count-sized kernel buffer and copy count from
userspace to that buffer. Later, we use kstrtouint on this buffer but we
don't ensure that the string is terminated inside the buffer, this can
lead to OOB read when using kstrtouint. Fix this issue by using
memdup_user_nul instead of memdup_user.

Fixes: 61d8658 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.")
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://lore.kernel.org/r/20240424-fix-oob-read-v2-4-f1f1b53a10f4@gmail.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from commit d0184a3)
Signed-off-by: John Meneghini <jmeneghi@redhat.com>

Author: johnmeneghini

drivers/scsi/qedf/qedf_debugfs.c

@@ -170,7 +170,7 @@ qedf_dbg_debug_cmd_write(struct file *filp, const char __user *buffer,
 	if (!count || *ppos)
 		return 0;
 
-	kern_buf = memdup_user(buffer, count);
+	kern_buf = memdup_user_nul(buffer, count);
 	if (IS_ERR(kern_buf))
 		return PTR_ERR(kern_buf);