[PATCH 4.5 148/200] misc: mic/scif: fix wrap around tests

Greg Kroah-Hartman
2016-05-03T00:50:14Z

From: Dan Carpenter <dan.carpenter@oracle.com>

commit 7b64dbf849abdd7e769820e25120758f956a7f13 upstream.

Signed integer overflow is undefined. Also I added a check for
"(offset < 0)" in scif_unregister() because that makes it match the
other conditions and because I didn't want to subtract a negative.

Fixes: ba612aa8b487 ('misc: mic: SCIF memory registration and unregistration')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/misc/mic/scif/scif_rma.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/misc/mic/scif/scif_rma.c
+++ b/drivers/misc/mic/scif/scif_rma.c
@@ -1511,7 +1511,7 @@ off_t scif_register_pinned_pages(scif_ep
if ((map_flags & SCIF_MAP_FIXED) &&
((ALIGN(offset, PAGE_SIZE) != offset) ||
(offset < 0) ||
- (offset + (off_t)len < offset)))
+ (len > LONG_MAX - offset)))
return -EINVAL;

might_sleep();
@@ -1614,7 +1614,7 @@ off_t scif_register(scif_epd_t epd, void
if ((map_flags & SCIF_MAP_FIXED) &&
((ALIGN(offset, PAGE_SIZE) != offset) ||
(offset < 0) ||
- (offset + (off_t)len < offset)))
+ (len > LONG_MAX - offset)))
return -EINVAL;

/* Unsupported protection requested */
@@ -1732,7 +1732,8 @@ scif_unregister(scif_epd_t epd, off_t of

/* Offset is not page aligned or offset+len wraps around */
if ((ALIGN(offset, PAGE_SIZE) != offset) ||
- (offset + (off_t)len < offset))
+ (offset < 0) ||
+ (len > LONG_MAX - offset))
return -EINVAL;

err = scif_verify_epd(ep);