From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CBEAC282CE for ; Wed, 24 Apr 2019 17:46:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CF5921773 for ; Wed, 24 Apr 2019 17:46:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556127978; bh=XXiYrON0C4xHGI6RqUGq+OUixt+Nb+T11hfDrSwNsY8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vbvBlg1k+n7kiwGaqV29QM/RqNq6AkKg1h/p2lSDJZQwQMW59oTFaUEw31d4zPiOh zLnVO4rLOdESuvQw0qpgJ7fSurHd/oLLtUGYMVmEX2H7PawSNZQfBXlJAJH2TWE7l2 cae4fqdq4P9fXRLiF4hLaPWzN21UTnmAHx60qKnI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391415AbfDXRcr (ORCPT ); Wed, 24 Apr 2019 13:32:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:59502 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391401AbfDXRco (ORCPT ); Wed, 24 Apr 2019 13:32:44 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 136E42054F; Wed, 24 Apr 2019 17:32:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556127163; bh=XXiYrON0C4xHGI6RqUGq+OUixt+Nb+T11hfDrSwNsY8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1KP7mmO1ni/Oc6p+xYZAfvufSYbGLFwqx5fu13wCdFLM7LQqDFl2/sFlEIo8HNI6h Z+oS/iexH5CJuEysBv6Mu3DivVoB1ZwV9Zx4zv9IL6VD6iFJ/rNGWGOPj3cbbKF7/6 9yCPwB5DgOp1og7IJFAlXigkRDJF29psecsoXgE8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ian Abbott Subject: [PATCH 4.19 49/96] staging: comedi: vmk80xx: Fix possible double-free of ->usb_rx_buf Date: Wed, 24 Apr 2019 19:09:54 +0200 Message-Id: <20190424170923.148546767@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170919.829037226@linuxfoundation.org> References: <20190424170919.829037226@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ian Abbott commit 663d294b4768bfd89e529e069bffa544a830b5bf upstream. `vmk80xx_alloc_usb_buffers()` is called from `vmk80xx_auto_attach()` to allocate RX and TX buffers for USB transfers. It allocates `devpriv->usb_rx_buf` followed by `devpriv->usb_tx_buf`. If the allocation of `devpriv->usb_tx_buf` fails, it frees `devpriv->usb_rx_buf`, leaving the pointer set dangling, and returns an error. Later, `vmk80xx_detach()` will be called from the core comedi module code to clean up. `vmk80xx_detach()` also frees both `devpriv->usb_rx_buf` and `devpriv->usb_tx_buf`, but `devpriv->usb_rx_buf` may have already been freed, leading to a double-free error. Fix it by removing the call to `kfree(devpriv->usb_rx_buf)` from `vmk80xx_alloc_usb_buffers()`, relying on `vmk80xx_detach()` to free the memory. Signed-off-by: Ian Abbott Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/vmk80xx.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/drivers/staging/comedi/drivers/vmk80xx.c +++ b/drivers/staging/comedi/drivers/vmk80xx.c @@ -682,10 +682,8 @@ static int vmk80xx_alloc_usb_buffers(str size = usb_endpoint_maxp(devpriv->ep_tx); devpriv->usb_tx_buf = kzalloc(size, GFP_KERNEL); - if (!devpriv->usb_tx_buf) { - kfree(devpriv->usb_rx_buf); + if (!devpriv->usb_tx_buf) return -ENOMEM; - } return 0; }