[SCSI] scsi_debug: fix map_region and unmap_region oops

map_region and unmap_region could access to invalid memory area since
they don't check the size boundary.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 136329b4027b..b02bdc6c2cd1 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1991,7 +1991,8 @@ static void map_region(sector_t lba, unsigned int len)
                 block = lba + alignment;
                 rem = do_div(block, granularity);
 
-                set_bit(block, map_storep);
+                if (block < map_size)
+                        set_bit(block, map_storep);
 
                 lba += granularity - rem;
         }
@@ -2011,7 +2012,8 @@ static void unmap_region(sector_t lba, unsigned int len)
                 block = lba + alignment;
                 rem = do_div(block, granularity);
 
-                if (rem == 0 && lba + granularity <= end)
+                if (rem == 0 && lba + granularity <= end &&
+                    block < map_size)
                         clear_bit(block, map_storep);
 
                 lba += granularity - rem;