From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Szymon Heidrich <szymon.heidrich@gmail.com>
Subject: [PATCH 4.9 30/42] USB: gadget: zero allocate endpoint 0 buffers
Date:   Mon, 13 Dec 2021 10:30:12 +0100
Message-Id: <20211213092927.548865564@linuxfoundation.org>
In-Reply-To: <20211213092926.578829548@linuxfoundation.org>
References: <20211213092926.578829548@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 86ebbc11bb3f60908a51f3e41a17e3f477c2eaa3 upstream.

Under some conditions, USB gadget devices can show allocated buffer
contents to a host.  Fix this up by zero-allocating them so that any
extra data will all just be zeros.

Reported-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Tested-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/gadget/composite.c   |    2 +-
 drivers/usb/gadget/legacy/dbgp.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -2183,7 +2183,7 @@ int composite_dev_prepare(struct usb_com
 	if (!cdev->req)
 		return -ENOMEM;
 
-	cdev->req->buf = kmalloc(USB_COMP_EP0_BUFSIZ, GFP_KERNEL);
+	cdev->req->buf = kzalloc(USB_COMP_EP0_BUFSIZ, GFP_KERNEL);
 	if (!cdev->req->buf)
 		goto fail;
 
--- a/drivers/usb/gadget/legacy/dbgp.c
+++ b/drivers/usb/gadget/legacy/dbgp.c
@@ -136,7 +136,7 @@ static int dbgp_enable_ep_req(struct usb
 		goto fail_1;
 	}
 
-	req->buf = kmalloc(DBGP_REQ_LEN, GFP_KERNEL);
+	req->buf = kzalloc(DBGP_REQ_LEN, GFP_KERNEL);
 	if (!req->buf) {
 		err = -ENOMEM;
 		stp = 2;