From: Colin King <colin.king@canonical.com>
To: Ian Abbott <abbotti@mev.co.uk>,
H Hartley Sweeten <hsweeten@visionengravers.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
devel@driverdev.osuosl.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] staging: comedi: dt2811: fix integer overflow in multiply
Date: Sat, 02 Feb 2019 21:59:16 +0000 [thread overview]
Message-ID: <20190202215916.25753-1-colin.king@canonical.com> (raw)
From: Colin Ian King <colin.king@canonical.com>
Multiplying two unsigned ints leads to an unsigned int result. The
intention is that the result is a unsigned long long, so to fix the
overflow cast the div to an unsigned long long to ensure that the
multiplication is on unsigned long longs to avoid overflow.
Detected by CoverityScan, CID#1357597 ("Unintentioal integer overflow")
Fixes: f2975a9b2ab9 ("staging: comedi: dt2811: add async command support for AI subdevice")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/staging/comedi/drivers/dt2811.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/comedi/drivers/dt2811.c b/drivers/staging/comedi/drivers/dt2811.c
index 05207a519755..820e75f850ff 100644
--- a/drivers/staging/comedi/drivers/dt2811.c
+++ b/drivers/staging/comedi/drivers/dt2811.c
@@ -323,7 +323,8 @@ static unsigned int dt2811_ns_to_timer(unsigned int *nanosec,
for (_mult = 0; _mult <= 7; _mult++) {
unsigned int div = dt2811_clk_dividers[_div];
unsigned int mult = dt2811_clk_multipliers[_mult];
- unsigned long long divider = div * mult;
+ unsigned long long divider + (unsigned long long)div * mult;
unsigned int divisor = DT2811_TMRCTR_MANTISSA(_div) |
DT2811_TMRCTR_EXPONENT(_mult);
--
2.20.1
next reply other threads:[~2019-02-02 21:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-02 21:59 Colin King [this message]
2019-02-03 11:29 ` [PATCH] staging: comedi: dt2811: fix integer overflow in multiply Dan Carpenter
2019-02-04 7:48 ` Dan Carpenter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190202215916.25753-1-colin.king@canonical.com \
--to=colin.king@canonical.com \
--cc=abbotti@mev.co.uk \
--cc=devel@driverdev.osuosl.org \
--cc=gregkh@linuxfoundation.org \
--cc=hsweeten@visionengravers.com \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox