From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH v10 3/7] i2c: fsi: Add port structures Date: Wed, 20 Jun 2018 13:34:15 +1000 Message-ID: <5d1f980286e2bba566421ebb29721770303fcf09.camel@kernel.crashing.org> References: <1528918579-27602-1-git-send-email-eajames@linux.vnet.ibm.com> <1528918579-27602-4-git-send-email-eajames@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1528918579-27602-4-git-send-email-eajames@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: Eddie James , linux-i2c@vger.kernel.org Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, wsa@the-dreams.de, robh+dt@kernel.org, joel@jms.id.au, mark.rutland@arm.com, gregkh@linuxfoundation.org, rdunlap@infradead.org, andy.shevchenko@gmail.com, peda@axentia.se List-Id: linux-i2c@vger.kernel.org On Wed, 2018-06-13 at 14:36 -0500, Eddie James wrote: > } > > +static int fsi_i2c_remove(struct device *dev) > +{ > + struct fsi_i2c_master *i2c = dev_get_drvdata(dev); > + struct fsi_i2c_port *port; > + > + list_for_each_entry(port, &i2c->ports, list) { > + i2c_del_adapter(&port->adapter); > + kfree(port); > + } > + > + return 0; > +} > + This is a use-after-free, the list linkage of the freed port is used to get to the next one. With memory poisoning, kbooom ! You can fold that in: >>From f9d9092160897e7308f6990067a03e937339537f Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 20 Jun 2018 13:27:32 +1000 Subject: [PATCH] i2c: fsi: Fix use after free Signed-off-by: Benjamin Herrenschmidt --- drivers/i2c/busses/i2c-fsi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c index 713959b44403..ff69ab6aa79a 100644 --- a/drivers/i2c/busses/i2c-fsi.c +++ b/drivers/i2c/busses/i2c-fsi.c @@ -696,9 +696,10 @@ static int fsi_i2c_probe(struct device *dev) static int fsi_i2c_remove(struct device *dev) { struct fsi_i2c_master *i2c = dev_get_drvdata(dev); - struct fsi_i2c_port *port; + struct fsi_i2c_port *port, *tmp; - list_for_each_entry(port, &i2c->ports, list) { + list_for_each_entry_safe(port,tmp, &i2c->ports, list) { + list_del(&port->list); i2c_del_adapter(&port->adapter); kfree(port); }