linux-kernel - [PATCH] iio: frequency: adf4371: Fix divide by zero exception bug

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 7 Jan 2020 15:15:59 +0200
From:   Beniamin Bia <beniamin.bia@...log.com>
To:     <jic23@...nel.org>
CC:     <lars@...afoo.de>, <Michael.Hennerich@...log.com>,
        <pmeerw@...erw.net>, <linux-iio@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <biabeniamin@...look.com>,
        <knaack.h@....de>,
        Michael Hennerich <michael.hennerich@...log.com>,
        Beniamin Bia <beniamin.bia@...log.com>
Subject: [PATCH] iio: frequency: adf4371: Fix divide by zero exception bug

From: Michael Hennerich <michael.hennerich@...log.com>

During initialization adf4371_pll_fract_n_get_rate() is called on all
output channels to determine if the device was setup. In this case
mod2 is zero which can cause a divide by zero exception.
Return before that can happen.

Fixes: 7f699bd149134 ("iio: frequency: adf4371: Add support for ADF4371 PLL")
Signed-off-by: Michael Hennerich <michael.hennerich@...log.com>
Signed-off-by: Beniamin Bia <beniamin.bia@...log.com>
---
 drivers/iio/frequency/adf4371.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iio/frequency/adf4371.c b/drivers/iio/frequency/adf4371.c
index e2a599b912e5..c21462238314 100644
--- a/drivers/iio/frequency/adf4371.c
+++ b/drivers/iio/frequency/adf4371.c
@@ -191,6 +191,9 @@ static unsigned long long adf4371_pll_fract_n_get_rate(struct adf4371_state *st,
 	unsigned long long val, tmp;
 	unsigned int ref_div_sel;
 
+	if (st->mod2 == 0)
+		return 0;
+
 	val = (((u64)st->integer * ADF4371_MODULUS1) + st->fract1) * st->fpfd;
 	tmp = (u64)st->fract2 * st->fpfd;
 	do_div(tmp, st->mod2);
-- 
2.17.1