From patchwork Wed Jan 22 04:07:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Ellerman X-Patchwork-Id: 11344973 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 98133109A for ; Wed, 22 Jan 2020 04:07:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D7EC2465B for ; Wed, 22 Jan 2020 04:07:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="iva23+yX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728916AbgAVEHd (ORCPT ); Tue, 21 Jan 2020 23:07:33 -0500 Received: from bilbo.ozlabs.org ([203.11.71.1]:54233 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727022AbgAVEHc (ORCPT ); Tue, 21 Jan 2020 23:07:32 -0500 Received: by ozlabs.org (Postfix, from userid 1034) id 482X1G3C2cz9sRR; Wed, 22 Jan 2020 15:07:30 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1579666050; bh=G7bbOYoKRp6jrs8GgGQz2ON95U4owgnlnz579hK3u2o=; h=From:To:Cc:Subject:Date:From; b=iva23+yXgpPhxd556QpzNZZ+YheLIZT1526j5B6Xr00lqX1DY/UcF1y5QwLPPn1Nq /bM0KMZARUT6MVYuFgJL7fN9GvAbN/S4x5yFX24I2MT0+mVb9JOGIbs+x8szKg6d11 XF+S07HUyPH6JC+lQaSM8MQzZzyEmMmeWXvoXbhkG/0zngeCeNnzyV3KfTFjZYrwJj fCn8kGzeCWPu/Rr6TCLRnJ53944/tlpZkTDFyZ3uEqKCBIHxH/PiFOFlvqFgjRXmOA Pf2dRKCaV9rmzMs9JY/pUhHRTpWkr258ul1XfEtFLMkcN6zm4gTHCw1JYWMlgt6yDU HnIIBz0I+A6Zg== From: Michael Ellerman To: netdev@vger.kernel.org Cc: linux-wireless@vger.kernel.org, kvalo@codeaurora.org, davem@davemloft.net, linux-kernel@vger.kernel.org, security@kernel.org, ivansprundel@ioactive.com Subject: [PATCH 1/2] airo: Fix possible info leak in AIROOLDIOCTL/SIOCDEVPRIVATE Date: Wed, 22 Jan 2020 15:07:27 +1100 Message-Id: <20200122040728.8437-1-mpe@ellerman.id.au> X-Mailer: git-send-email 2.21.1 MIME-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org The driver for Cisco Aironet 4500 and 4800 series cards (airo.c), implements AIROOLDIOCTL/SIOCDEVPRIVATE in airo_ioctl(). The ioctl handler copies an aironet_ioctl struct from userspace, which includes a command and a length. Some of the commands are handled in readrids(), which kmalloc()'s a buffer of RIDSIZE (2048) bytes. That buffer is then passed to PC4500_readrid(), which has two cases. The else case does some setup and then reads up to RIDSIZE bytes from the hardware into the kmalloc()'ed buffer. Here len == RIDSIZE, pBuf is the kmalloc()'ed buffer: // read the rid length field bap_read(ai, pBuf, 2, BAP1); // length for remaining part of rid len = min(len, (int)le16_to_cpu(*(__le16*)pBuf)) - 2; ... // read remainder of the rid rc = bap_read(ai, ((__le16*)pBuf)+1, len, BAP1); PC4500_readrid() then returns to readrids() which does: len = comp->len; if (copy_to_user(comp->data, iobuf, min(len, (int)RIDSIZE))) { Where comp->len is the user controlled length field. So if the "rid length field" returned by the hardware is < 2048, and the user requests 2048 bytes in comp->len, we will leak the previous contents of the kmalloc()'ed buffer to userspace. Fix it by kzalloc()'ing the buffer. Found by Ilja by code inspection, not tested as I don't have the required hardware. Reported-by: Ilja Van Sprundel Signed-off-by: Michael Ellerman --- drivers/net/wireless/cisco/airo.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c index f43c06569ea1..d69c2ee7e206 100644 --- a/drivers/net/wireless/cisco/airo.c +++ b/drivers/net/wireless/cisco/airo.c @@ -7813,7 +7813,7 @@ static int readrids(struct net_device *dev, aironet_ioctl *comp) { return -EINVAL; } - if ((iobuf = kmalloc(RIDSIZE, GFP_KERNEL)) == NULL) + if ((iobuf = kzalloc(RIDSIZE, GFP_KERNEL)) == NULL) return -ENOMEM; PC4500_readrid(ai,ridcode,iobuf,RIDSIZE, 1);