From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/lJuzaxpPF2LI0m/kx20a2VXhvv3m/nskLKyXyYg0KM8e/5FtHye4GUGnIOMlDoW7gr5xi ARC-Seal: i=1; a=rsa-sha256; t=1523021540; cv=none; d=google.com; s=arc-20160816; b=bqVOt7XwqFear+Ul85rfqI6fKgzm4rIpfLKwp3344HhF6mmvDA3cD3zbC4umStTn5Z mQ3hC6USXbiMta512v3vsPogfrk5lkUsl/fUbjDgkwfb2ve/t/Bjr2OlRG19USesvE3H CljR4mYF7B6nFWH8GCDopk2zxyBRVNiE4n6dnc2NSQFCvfYli67U/Jzaa/B22b8F/XWP ghqZNe/cccI0xQ35jyLTb2UUxhT/5jW5eQ1nP+PSSM2a7jLx2b6/SRv9bkTT7TRXsBgl 5XV1FGEmlU15qsLG6hiCESZGCsY2EJFxK0oLrSo0oa8NNBCvtK/2/ZlPrO5ux0CTHUVe Q8WQ== 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=LU8Lh3MMYd3K2I2PsBjBbI7NjJJYFYpZKAiALJx+DCM=; b=clwLirAotuh4zybtyYVRWo838i7vrgJ7rGzibbiF98mNwFWGLukcKWV5KkNnNYBcPm syik4sfu7JOWV5OKH45a10RSaJoqhFyt+M7C4QF9oNMWCwlTQ8f/klyRdloAntZdqsFP piSIiPXKncS/rSGRqMRAH8eJ2AOayvvFteXAmcVQrNZq6zcM1+MLFzGUBmSHxm+nd8yA vuBfigVxEYZaJWaFlnqONrbNOQTJOi97DAjGQmfbTRGqWkRZZ0ahWa47T2pzl5/MXkvv y+oW5t4UhZrfyy4QWEtzLzyrPwfmQDP3S52kXDRXjtCl0xPzEHx9tB6A+m+iNVN2ydJ3 WFyQ== 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 4.4 49/72] media: usbtv: prevent double free in error case Date: Fri, 6 Apr 2018 15:23:50 +0200 Message-Id: <20180406084309.317246829@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180406084305.210085169@linuxfoundation.org> References: <20180406084305.210085169@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?1597003835146480498?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-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: