linux-hardening - [PATCH] cpufreq: powernow: Prefer kcalloc over open coded arithmetic

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]

Message-Id: <20210904151628.6618-1-len.baker@gmx.com>
Date:   Sat,  4 Sep 2021 17:16:28 +0200
From:   Len Baker <len.baker@....com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Len Baker <len.baker@....com>, Kees Cook <keescook@...omium.org>,
        linux-pm@...r.kernel.org, linux-hardening@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] cpufreq: powernow: Prefer kcalloc over open coded arithmetic

As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

So, use the purpose specific kcalloc() function instead of the argument
size * count in the kzalloc() function.

[1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

Signed-off-by: Len Baker <len.baker@....com>
---
 drivers/cpufreq/powernow-k7.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/powernow-k7.c b/drivers/cpufreq/powernow-k7.c
index 5d515fc34836..a9d2c7bae235 100644
--- a/drivers/cpufreq/powernow-k7.c
+++ b/drivers/cpufreq/powernow-k7.c
@@ -174,8 +174,8 @@ static int get_ranges(unsigned char *pst)
 	unsigned int speed;
 	u8 fid, vid;

-	powernow_table = kzalloc((sizeof(*powernow_table) *
-				(number_scales + 1)), GFP_KERNEL);
+	powernow_table = kcalloc(number_scales + 1, sizeof(*powernow_table),
+				 GFP_KERNEL);
 	if (!powernow_table)
 		return -ENOMEM;

--
2.25.1