scsi: sg: allocate with __GFP_ZERO in sg_build_indirect()

commit a45b599ad808c3c982fdcdc12b0b8611c2f92824 upstream.

This shall help avoid copying uninitialized memory to the userspace when
calling ioctl(fd, SG_IO) with an empty command.

Reported-by: syzbot+7d26fc1eea198488deab@syzkaller.appspotmail.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 0206b495b65e7c2a89ce8a6ccf4db2ffd478dc2d..cc4e3f1c204b6cd170f72ed3968042ec9fdfa0d0 100644 (file)
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1825,7 +1825,7 @@ retry:
                num = (rem_sz > scatter_elem_sz_prev) ?
                        scatter_elem_sz_prev : rem_sz;
 
-               schp->pages[k] = alloc_pages(gfp_mask, order);
+               schp->pages[k] = alloc_pages(gfp_mask | __GFP_ZERO, order);
                if (!schp->pages[k])
                        goto out;