From mboxrd@z Thu Jan 1 00:00:00 1970 From: Colin Ian King Date: Tue, 15 Sep 2020 17:14:42 +0000 Subject: Re: [PATCH] media: rc: fix check on dev->min_timeout for LIRC_GET_MIN_TIMEOUT ioctl Message-Id: List-Id: References: <20200915153608.35154-1-colin.king@canonical.com> <20200915171256.GA681@gofer.mess.org> In-Reply-To: <20200915171256.GA681@gofer.mess.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Sean Young Cc: Mauro Carvalho Chehab , Maxim Levitsky , linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org On 15/09/2020 18:12, Sean Young wrote: > 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? Oops. I totally misread the analysis report. My bad. > > 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