[PATCH v2 1/4] ses: fix slab-out-of-bounds reported by KASAN in ses_enclosure_data_process

[Tomas Henzl <thenzl@redhat.com>]

A fix for:
BUG: KASAN: slab-out-of-bounds in ses_enclosure_data_process+0x949/0xe30 [ses]
Read of size 1 at addr ffff88a1b043a451 by task systemd-udevd/3271
Checking after (and before in next loop) addl_desc_ptr[1] is sufficient,
we expect the size to be sanitized before first access to addl_desc_ptr[1].
Testing for one more byte shall protect partially the ses_process_descriptor.

Signed-off-by: Tomas Henzl <thenzl@redhat.com>
---
 drivers/scsi/ses.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index 0a1734f34587..1ee927ac8603 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -603,9 +603,11 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
 			     /* these elements are optional */
 			     type_ptr[0] == ENCLOSURE_COMPONENT_SCSI_TARGET_PORT ||
 			     type_ptr[0] == ENCLOSURE_COMPONENT_SCSI_INITIATOR_PORT ||
-			     type_ptr[0] == ENCLOSURE_COMPONENT_CONTROLLER_ELECTRONICS))
+			     type_ptr[0] == ENCLOSURE_COMPONENT_CONTROLLER_ELECTRONICS)){
 				addl_desc_ptr += addl_desc_ptr[1] + 2;
-
+				if (addl_desc_ptr + 1 >= ses_dev->page10 + ses_dev->page10_len)
+					addl_desc_ptr = NULL;
+			}
 		}
 	}
 	kfree(buf);
-- 
2.38.1