UPSTREAM: scsi: qla2xxx: Fix an integer overflow in sysfs code

The value of "size" comes from the user.  When we add "start + size" it
could lead to an integer overflow bug.

It means we vmalloc() a lot more memory than we had intended.  I believe
that on 64 bit systems vmalloc() can succeed even if we ask it to
allocate huge 4GB buffers.  So we would get memory corruption and likely
a crash when we call ha->isp_ops->write_optrom() and ->read_optrom().

Only root can trigger this bug.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=194061

BUG=chromium:761615
TEST=Build and run

Change-Id: I00e345983bf5f86cc0c654cb113180faa7b68be7
Cc: <stable@vger.kernel.org>
Fixes: b7cc176c9eb3 ("[SCSI] qla2xxx: Allow region-based flash-part accesses.")
Reported-by: shqking <shqking@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Guenter Roeck <groeck@chromium.org>
(cherry picked from commit e6f77540c067)
Reviewed-on: https://chromium-review.googlesource.com/660408
Reviewed-by: Dylan Reid <dgreid@chromium.org>
1 file changed