From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+eqyYt1y2SaK3OAW6Iwbac47wMkr0H8uPprqMf+5IyrFMh8vEZCKSv+XtjJMCFETAi0GZB ARC-Seal: i=1; a=rsa-sha256; t=1523021300; cv=none; d=google.com; s=arc-20160816; b=WTnoY0InZdYy/outdrZq4PMIBOO/AvYCrjMLmUEfCMfYdVUeLu3V6wJ94+59s0v/o/ NlZ5BT+G26KybyL8FnpCyNsYpilJTAYNqswoxwMUxYWoHISdvqYMk7ootRFJBGxbjWgj fWooOu1iK3BdUM9N98SGE8HHx8kMqI1KHVwkATprOctiQGEl2mq6AnhezNDVcaiPJKix ID9i2zEIJa3M7j9DPVRgILOUiQ25sRooK+8i4b93tN51AfuGAX0WEMwWdTiBbvi6IXwB C47qiz6dFWJj+sg5aQXwDlqzjOB5BGS6c/s2mpTs2YWUDzjPYlEntG2tTK+N3juBz4lA +4CQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=18dKjHAGpV+EA22cHsOz7y+iYgFT8ZCvgha0u86wFL4=; b=p3dojPEI2W1LGQp991d+o9KoVBF4xvNEQuWV+AlJED3KJRMlYMKzTiU9Eddl3Wt9Dk IBwhDBxOogRO9EsNwJ8Ltc9IHm8CSFDYwHO5DEDMv0guET7pRxrNXJrnTUcEROGb+/Bu exm9OaSglNp3GEAFhio1jKSeUfguf6Xdqh+at/p9zHG1FeWaeitDlYb9oJfgG8OMGpLD khNL09eN0mxDjL83SBRoms5XQwHioovKFKTHiJZAep0M2DIuBwcnQORlqJjvheFop+XE 8j74/u3W+wfe/LXSM59vNdeNjA8zIAwRhlKOPNht2+0OrvUtN2mRt9gWxxLMRuAaB8Hz EG4A== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Yavuz, Tuba" , Oliver Neukum , Hans Verkuil , Mauro Carvalho Chehab Subject: [PATCH 3.18 79/93] media: usbtv: prevent double free in error case Date: Fri, 6 Apr 2018 15:23:48 +0200 Message-Id: <20180406084228.620670984@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180406084224.918716300@linuxfoundation.org> References: <20180406084224.918716300@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597003583168556365?= X-GMAIL-MSGID: =?utf-8?q?1597003583168556365?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Neukum commit 50e7044535537b2a54c7ab798cd34c7f6d900bd2 upstream. Quoting the original report: It looks like there is a double-free vulnerability in Linux usbtv driver on an error path of usbtv_probe function. When audio registration fails, usbtv_video_free function ends up freeing usbtv data structure, which gets freed the second time under usbtv_video_fail label. usbtv_audio_fail: usbtv_video_free(usbtv); => v4l2_device_put(&usbtv->v4l2_dev); => v4l2_device_put => kref_put => v4l2_device_release => usbtv_release (CALLBACK) => kfree(usbtv) (1st time) usbtv_video_fail: usb_set_intfdata(intf, NULL); usb_put_dev(usbtv->udev); kfree(usbtv); (2nd time) So, as we have refcounting, use it Reported-by: Yavuz, Tuba Signed-off-by: Oliver Neukum CC: stable@vger.kernel.org Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/usbtv/usbtv-core.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/media/usb/usbtv/usbtv-core.c +++ b/drivers/media/usb/usbtv/usbtv-core.c @@ -95,6 +95,8 @@ static int usbtv_probe(struct usb_interf return 0; usbtv_audio_fail: + /* we must not free at this point */ + usb_get_dev(usbtv->udev); usbtv_video_free(usbtv); usbtv_video_fail: