[patch] [SCSI] megaraid: missing bounds check in mimd_to_kioc()

[Dan Carpenter <dan.carpenter@oracle.com>]

pthru32->dataxferlen comes from the user so we need to check that it's
not too large so we don't overflow the buffer.

Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Please review this carefully because I have not tested it.

diff --git a/drivers/scsi/megaraid/megaraid_mm.c b/drivers/scsi/megaraid/megaraid_mm.c
index dfffd0f..a706927 100644
--- a/drivers/scsi/megaraid/megaraid_mm.c
+++ b/drivers/scsi/megaraid/megaraid_mm.c
@@ -486,6 +486,8 @@ mimd_to_kioc(mimd_t __user *umimd, mraid_mmadp_t *adp, uioc_t *kioc)
 
 	pthru32->dataxferaddr	= kioc->buf_paddr;
 	if (kioc->data_dir & UIOC_WR) {
+		if (pthru32->dataxferlen > kioc->xferlen)
+			return -EINVAL;
 		if (copy_from_user(kioc->buf_vaddr, kioc->user_data,
 						pthru32->dataxferlen)) {
 			return (-EFAULT);