From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Young Date: Tue, 15 Sep 2020 17:12:56 +0000 Subject: Re: [PATCH] media: rc: fix check on dev->min_timeout for LIRC_GET_MIN_TIMEOUT ioctl Message-Id: <20200915171256.GA681@gofer.mess.org> List-Id: References: <20200915153608.35154-1-colin.king@canonical.com> In-Reply-To: <20200915153608.35154-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Colin King Cc: Mauro Carvalho Chehab , Maxim Levitsky , linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org On Tue, Sep 15, 2020 at 04:36:08PM +0100, Colin King wrote: > From: Colin Ian King > > Currently the LIRC_GET_MIN_TIMEOUT is checking for a null dev->max_timeout > and then accessing dev->min_timeout, hence we may have a potential null > pointer dereference issue. This looks like a cut-n-paste typo, fix it > by checking on dev->min_timeout before accessing it. max_timeout and min_timeout are both u32, not pointers. So, the commit message is wrong: there is no null pointer dereference issue. Every driver which has max_timeout also has min_timeout set (I've checked for this). So technically this is not wrong, but maybe it looks wrong? Thanks, Sean > > Addresses-Coverity: ("Copy-paste error") > Fixes: e589333f346b ("V4L/DVB: IR: extend interfaces to support more device settings") > Signed-off-by: Colin Ian King > --- > drivers/media/rc/lirc_dev.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/rc/lirc_dev.c b/drivers/media/rc/lirc_dev.c > index 220363b9a868..d230c21e1d31 100644 > --- a/drivers/media/rc/lirc_dev.c > +++ b/drivers/media/rc/lirc_dev.c > @@ -533,7 +533,7 @@ static long lirc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > > /* Generic timeout support */ > case LIRC_GET_MIN_TIMEOUT: > - if (!dev->max_timeout) > + if (!dev->min_timeout) > ret = -ENOTTY; > else > val = dev->min_timeout; > -- > 2.27.0