From: Alan Stern <stern@rowland.harvard.edu>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Greg KH <greg@kroah.com>,
syzbot <syzbot+30cf45ebfe0b0c4847a1@syzkaller.appspotmail.com>,
Bjorn Helgaas <bhelgaas@google.com>, <kirr@nexedi.com>,
Kernel development list <linux-kernel@vger.kernel.org>,
USB list <linux-usb@vger.kernel.org>,
Guenter Roeck <linux@roeck-us.net>, <lkundrak@v3.sk>,
<logang@deltatee.com>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: KASAN: use-after-free Read in ld_usb_release
Date: Mon, 12 Aug 2019 10:21:14 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1908121020180.1659-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <CAAeHK+xZgjD+gP=pCkk0uKVkuPG+XZ26mgNQCGzw2ea5mqFTJg@mail.gmail.com>
On Mon, 12 Aug 2019, Andrey Konovalov wrote:
> Alan, could you submit this patch (if you haven't already)? Looks like
> it fixes this bug (and might fix some others).
I will. I was waiting to see if Greg KH had any comments.
Alan Stern
> > drivers/usb/core/file.c | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > Index: usb-devel/drivers/usb/core/file.c
> > ===================================================================
> > --- usb-devel.orig/drivers/usb/core/file.c
> > +++ usb-devel/drivers/usb/core/file.c
> > @@ -193,9 +193,10 @@ int usb_register_dev(struct usb_interfac
> > intf->minor = minor;
> > break;
> > }
> > - up_write(&minor_rwsem);
> > - if (intf->minor < 0)
> > + if (intf->minor < 0) {
> > + up_write(&minor_rwsem);
> > return -EXFULL;
> > + }
> >
> > /* create a usb class device for this usb interface */
> > snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
> > @@ -203,12 +204,11 @@ int usb_register_dev(struct usb_interfac
> > MKDEV(USB_MAJOR, minor), class_driver,
> > "%s", kbasename(name));
> > if (IS_ERR(intf->usb_dev)) {
> > - down_write(&minor_rwsem);
> > usb_minors[minor] = NULL;
> > intf->minor = -1;
> > - up_write(&minor_rwsem);
> > retval = PTR_ERR(intf->usb_dev);
> > }
> > + up_write(&minor_rwsem);
> > return retval;
> > }
> > EXPORT_SYMBOL_GPL(usb_register_dev);
> > @@ -234,12 +234,12 @@ void usb_deregister_dev(struct usb_inter
> > return;
> >
> > dev_dbg(&intf->dev, "removing %d minor\n", intf->minor);
> > + device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
> >
> > down_write(&minor_rwsem);
> > usb_minors[intf->minor] = NULL;
> > up_write(&minor_rwsem);
> >
> > - device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
> > intf->usb_dev = NULL;
> > intf->minor = -1;
> > destroy_usb_class();
next prev parent reply other threads:[~2019-08-12 14:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 13:18 KASAN: use-after-free Read in ld_usb_release syzbot
2019-08-09 16:51 ` Alan Stern
2019-08-09 17:33 ` Andrey Konovalov
2019-08-09 17:53 ` syzbot
2019-08-12 12:07 ` Andrey Konovalov
2019-08-12 14:21 ` Alan Stern [this message]
2019-08-12 14:31 ` Greg KH
2019-08-12 15:31 ` Greg KH
2019-08-12 20:11 ` [PATCH] USB: core: Fix races in character device registration and deregistraion Alan Stern
2019-08-12 20:52 ` Greg KH
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