From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 10 Feb 2017 08:57:56 -0700 From: Scott Bauer To: Arnd Bergmann Subject: Re: [PATCH V3 2/2] Move stack parameters for sed_ioctl to prevent oversized stack with CONFIG_KASAN Message-ID: <20170210155755.GA2734@sbauer-Z170X-UD5> References: <1486660801-5105-1-git-send-email-scott.bauer@intel.com> <1486660801-5105-3-git-send-email-scott.bauer@intel.com> <4455227.qpXP0b5apU@wuerfel> MIME-Version: 1.0 In-Reply-To: <4455227.qpXP0b5apU@wuerfel> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: keith.busch@intel.com, hch@infradead.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, axboe@fb.com, David.Laight@aculab.com, linux-block@vger.kernel.org, jonathan.derrick@intel.com Content-Type: text/plain; charset="us-ascii" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+axboe=kernel.dk@lists.infradead.org List-ID: On Fri, Feb 10, 2017 at 09:01:23AM +0100, Arnd Bergmann wrote: > On Thursday, February 9, 2017 10:20:01 AM CET Scott Bauer wrote: > > When CONFIG_KASAN is enabled, compilation fails: > > > > block/sed-opal.c: In function 'sed_ioctl': > > block/sed-opal.c:2447:1: error: the frame size of 2256 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] > > > > Moved all the ioctl structures off the stack and dynamically activate > > using _IOC_SIZE() > > > > Fixes: 455a7b238cd6 ("block: Add Sed-opal library") > > > > Reported-by: Arnd Bergmann > > Signed-off-by: Scott Bauer > > --- > > block/sed-opal.c | 134 +++++++++++++++++++++---------------------------------- > > 1 file changed, 50 insertions(+), 84 deletions(-) > > > > diff --git a/block/sed-opal.c b/block/sed-opal.c > > index bf1406e..4985d95 100644 > > --- a/block/sed-opal.c > > +++ b/block/sed-opal.c > > @@ -2346,7 +2346,10 @@ EXPORT_SYMBOL(opal_unlock_from_suspend); > > > > int sed_ioctl(struct opal_dev *dev, unsigned int cmd, unsigned long ptr) > > { > > + void *ioctl_ptr; > > + int ret = -ENOTTY; > > void __user *arg = (void __user *)ptr; > > + unsigned int cmd_size = _IOC_SIZE(cmd); > > > > if (!capable(CAP_SYS_ADMIN)) > > return -EACCES; > > We usually have a size check in there to avoid allocating large amounts > of memory. _IOC_SIZEBITS is 14, so you can have up to 16kb here, which > is probably ok, but I'd recommend either adding a comment to say that > it is, or just checking against the largest realistic size. Right now it's up to the storage driver to call into the sed-opal ioctl. We have a function is_sed_ioctl() which is called before jumping into sed_ioctl. So we will be weeding out any non opal ioctls before getting in there so I don't see any overly large 16kb allocations happening. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme