Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Peilin Ye <yepeilin.cs@gmail.com>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Peilin Ye <yepeilin.cs@gmail.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel-mentees@lists.linuxfoundation.org,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [Linux-kernel-mentees] [PATCH v2] block/scsi-ioctl: Prevent kernel-infoleak in scsi_put_cdrom_generic_arg()
Date:   Mon, 27 Jul 2020 15:00:13 -0400
Message-Id: <20200727190013.324812-1-yepeilin.cs@gmail.com>
In-Reply-To: <20200727161932.322955-1-yepeilin.cs@gmail.com>
References: <20200727161932.322955-1-yepeilin.cs@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

scsi_put_cdrom_generic_arg() is copying uninitialized stack memory to
userspace due to the compiler not initializing holes in statically
allocated structures. Fix it by adding a padding field to `struct
compat_cdrom_generic_command`.

Cc: stable@vger.kernel.org
Fixes: f3ee6e63a9df ("compat_ioctl: move CDROM_SEND_PACKET handling into scsi")
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Change in v2:
    - Add a padding field to `struct compat_cdrom_generic_command`,
      instead of doing memset() on `cgc32`. (Suggested by Jens Axboe
      <axboe@kernel.dk>)

 block/scsi_ioctl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index ef722f04f88a..72108404718f 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -651,6 +651,7 @@ struct compat_cdrom_generic_command {
 	compat_int_t	stat;
 	compat_caddr_t	sense;
 	unsigned char	data_direction;
+	unsigned char	pad[3];
 	compat_int_t	quiet;
 	compat_int_t	timeout;
 	compat_caddr_t	reserved[1];
-- 
2.25.1