From: Alan Stern <stern@rowland.harvard.edu>
To: syzbot <syzbot+200d4bb11b23d929335f@syzkaller.appspotmail.com>
Cc: andreyknvl@google.com, <chunkeey@gmail.com>,
<chunkeey@googlemail.com>, <davem@davemloft.net>,
<kvalo@codeaurora.org>, <linux-kernel@vger.kernel.org>,
<linux-usb@vger.kernel.org>, <linux-wireless@vger.kernel.org>,
<netdev@vger.kernel.org>, <oneukum@suse.com>,
<syzkaller-bugs@googlegroups.com>
Subject: Re: KASAN: use-after-free Read in p54u_load_firmware_cb
Date: Sat, 18 May 2019 13:49:49 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1905181346380.10594-100000@netrider.rowland.org> (raw)
In-Reply-To: <000000000000b8203405892cee43@google.com>
On Sat, 18 May 2019, syzbot wrote:
> Hello,
>
> syzbot has tested the proposed patch but the reproducer still triggered
> crash:
> KASAN: use-after-free Read in usb_driver_release_interface
>
> usb 1-1: Loading firmware file isl3887usb
> usb 1-1: Direct firmware load for isl3887usb failed with error -2
> usb 1-1: Firmware not found.
> p54usb 1-1:0.143: failed to initialize device (-2)
> ==================================================================
> BUG: KASAN: use-after-free in usb_driver_release_interface+0x16b/0x190
> drivers/usb/core/driver.c:584
> Read of size 8 at addr ffff88808fc31218 by task kworker/0:1/12
Now the bad access is in a different place. That's a good sign.
In this case it indicates that although udev is still hanging around,
intf has already been freed. We really should acquire a reference to
it instead.
Alan Stern
#syz test: https://github.com/google/kasan.git usb-fuzzer
drivers/net/wireless/intersil/p54/p54usb.c | 43 ++++++++++++-----------------
1 file changed, 18 insertions(+), 25 deletions(-)
Index: usb-devel/drivers/net/wireless/intersil/p54/p54usb.c
===================================================================
--- usb-devel.orig/drivers/net/wireless/intersil/p54/p54usb.c
+++ usb-devel/drivers/net/wireless/intersil/p54/p54usb.c
@@ -33,6 +33,8 @@ MODULE_ALIAS("prism54usb");
MODULE_FIRMWARE("isl3886usb");
MODULE_FIRMWARE("isl3887usb");
+static struct usb_driver p54u_driver;
+
/*
* Note:
*
@@ -921,9 +923,9 @@ static void p54u_load_firmware_cb(const
{
struct p54u_priv *priv = context;
struct usb_device *udev = priv->udev;
+ struct usb_interface *intf = priv->intf;
int err;
- complete(&priv->fw_wait_load);
if (firmware) {
priv->fw = firmware;
err = p54u_start_ops(priv);
@@ -932,26 +934,22 @@ static void p54u_load_firmware_cb(const
dev_err(&udev->dev, "Firmware not found.\n");
}
- if (err) {
- struct device *parent = priv->udev->dev.parent;
-
- dev_err(&udev->dev, "failed to initialize device (%d)\n", err);
-
- if (parent)
- device_lock(parent);
+ complete(&priv->fw_wait_load);
+ /*
+ * At this point p54u_disconnect may have already freed
+ * the "priv" context. Do not use it anymore!
+ */
+ priv = NULL;
- device_release_driver(&udev->dev);
- /*
- * At this point p54u_disconnect has already freed
- * the "priv" context. Do not use it anymore!
- */
- priv = NULL;
+ if (err) {
+ dev_err(&intf->dev, "failed to initialize device (%d)\n", err);
- if (parent)
- device_unlock(parent);
+ usb_lock_device(udev);
+ usb_driver_release_interface(&p54u_driver, intf);
+ usb_unlock_device(udev);
}
- usb_put_dev(udev);
+ usb_put_intf(intf);
}
static int p54u_load_firmware(struct ieee80211_hw *dev,
@@ -972,14 +970,14 @@ static int p54u_load_firmware(struct iee
dev_info(&priv->udev->dev, "Loading firmware file %s\n",
p54u_fwlist[i].fw);
- usb_get_dev(udev);
+ usb_get_intf(intf);
err = request_firmware_nowait(THIS_MODULE, 1, p54u_fwlist[i].fw,
device, GFP_KERNEL, priv,
p54u_load_firmware_cb);
if (err) {
dev_err(&priv->udev->dev, "(p54usb) cannot load firmware %s "
"(%d)!\n", p54u_fwlist[i].fw, err);
- usb_put_dev(udev);
+ usb_put_intf(intf);
}
return err;
@@ -1011,8 +1009,6 @@ static int p54u_probe(struct usb_interfa
skb_queue_head_init(&priv->rx_queue);
init_usb_anchor(&priv->submitted);
- usb_get_dev(udev);
-
/* really lazy and simple way of figuring out if we're a 3887 */
/* TODO: should just stick the identification in the device table */
i = intf->altsetting->desc.bNumEndpoints;
@@ -1053,10 +1049,8 @@ static int p54u_probe(struct usb_interfa
priv->upload_fw = p54u_upload_firmware_net2280;
}
err = p54u_load_firmware(dev, intf);
- if (err) {
- usb_put_dev(udev);
+ if (err)
p54_free_common(dev);
- }
return err;
}
@@ -1072,7 +1066,6 @@ static void p54u_disconnect(struct usb_i
wait_for_completion(&priv->fw_wait_load);
p54_unregister_common(dev);
- usb_put_dev(interface_to_usbdev(intf));
release_firmware(priv->fw);
p54_free_common(dev);
}
next prev parent reply other threads:[~2019-05-18 17:49 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-06 11:16 KASAN: use-after-free Read in p54u_load_firmware_cb syzbot
2019-05-13 10:23 ` syzbot
2019-05-13 13:28 ` Oliver Neukum
2019-05-17 19:21 ` Christian Lamparter
2019-05-17 20:46 ` Alan Stern
2019-05-17 21:01 ` syzbot
2019-05-18 15:13 ` Alan Stern
2019-05-18 15:50 ` syzbot
2019-05-18 16:32 ` Alan Stern
2019-05-18 16:50 ` syzbot
2019-05-18 17:01 ` Alan Stern
2019-05-18 17:36 ` syzbot
2019-05-18 17:49 ` Alan Stern [this message]
2019-05-18 18:31 ` syzbot
2019-05-18 20:11 ` Christian Lamparter
2019-05-20 14:44 ` [PATCH] network: wireless: p54u: Fix race between disconnect and firmware loading Alan Stern
2019-05-24 21:19 ` Christian Lamparter
2019-05-28 12:11 ` Kalle Valo
2019-05-28 14:17 ` Alan Stern
2019-05-28 14:29 ` Kalle Valo
2019-06-25 4:43 ` [PATCH] p54usb: " Kalle Valo
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