From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] drivers/net/wimax/i2400m/fw.c fix possible double free Date: Tue, 16 Mar 2010 14:14:45 -0700 (PDT) Message-ID: <20100316.141445.27416807.davem@davemloft.net> References: <1268739988.17270.8.camel@ICE-BOX> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: inaky.perez-gonzalez@intel.com, linux-wimax@intel.com, kernel-janitors@vger.kernel.org, cindy.h.kao@intel.com, dirk.j.brandewie@intel.com, wimax@linuxwimax.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: darrenrjenkins@gmail.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:46828 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754364Ab0CPVOX (ORCPT ); Tue, 16 Mar 2010 17:14:23 -0400 In-Reply-To: <1268739988.17270.8.camel@ICE-BOX> Sender: netdev-owner@vger.kernel.org List-ID: From: Darren Jenkins Date: Tue, 16 Mar 2010 22:46:28 +1100 > i2400m_fw_check() can free i2400m->fw_hdrs if krealloc() fails causing a double free > Add a check so we don't free the memory a second time. > > coverity CID: 13455 > > Signed-off-by: Darren Jenkins Please don't fix it like this, the check is obscure and it's allowing other bugs to happen. If krealloc() fails, any refrence to i2400m->fw_hdrs is referencing freed memory. Therefore the krealloc() failure handling in this driver should NULL out i2400m->fw_hdrs and that will fix the double kfree problem as well as trap any stray references. > --- > drivers/net/wimax/i2400m/fw.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/drivers/net/wimax/i2400m/fw.c b/drivers/net/wimax/i2400m/fw.c > index 25c24f0..a97c413 100644 > --- a/drivers/net/wimax/i2400m/fw.c > +++ b/drivers/net/wimax/i2400m/fw.c > @@ -1490,7 +1490,8 @@ int i2400m_fw_bootstrap(struct i2400m *i2400m, const struct firmware *fw, > if (ret < 0) > dev_err(dev, "%s: cannot use: %d, skipping\n", > i2400m->fw_name, ret); > - kfree(i2400m->fw_hdrs); > + if (ret != -ENOMEM) > + kfree(i2400m->fw_hdrs); > i2400m->fw_hdrs = NULL; > d_fnend(5, dev, "(i2400m %p) = %d\n", i2400m, ret); > return ret; > -- > 1.6.3.3