misc: mic/scif: fix wrap around tests

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>

diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c
index 8310b4dbff0602ea5f4bd50f3ce87a9e58e854a7..6a451bd65bf3f8914586e3916f39c847730f15a8 100644 (file)
--- 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_epd_t epd,
        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 *addr, size_t len, off_t offset,
        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 offset, size_t len)
 
        /* 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);