From: Kees Cook <keescook@chromium.org>
To: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Markus Mayer <mmayer@broadcom.com>,
Broadcom internal kernel review list
<bcm-kernel-feedback-list@broadcom.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Florian Fainelli <florian.fainelli@broadcom.com>,
linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2] cpufreq: brcmstb-avs-cpufreq: Fix -Warray-bounds bug
Date: Mon, 31 Jul 2023 16:16:58 -0700 [thread overview]
Message-ID: <202307311610.B1EB796684@keescook> (raw)
In-Reply-To: <ZMgiiEmBORZRaobc@work>
On Mon, Jul 31, 2023 at 03:07:20PM -0600, Gustavo A. R. Silva wrote:
> Update the iteration conditions in the for() loop to avoid writing in
> array `table` beyond its allocated size at:
>
> drivers/cpufreq/brcmstb-avs-cpufreq.c:
> 449 table[i].frequency = CPUFREQ_TABLE_END;
>
> This fixes the following -Warray-bounds warning seen after building
> ARM with multi_v7_defconfig (GCC 13):
> In function 'brcm_avs_get_freq_table',
> inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
> drivers/cpufreq/brcmstb-avs-cpufreq.c:449:28: warning: array subscript 5 is outside array bounds of 'void[60]' [-Warray-bounds=]
> 449 | table[i].frequency = CPUFREQ_TABLE_END;
#define AVS_PSTATE_P0 0x0
#define AVS_PSTATE_P1 0x1
#define AVS_PSTATE_P2 0x2
#define AVS_PSTATE_P3 0x3
#define AVS_PSTATE_P4 0x4
#define AVS_PSTATE_MAX AVS_PSTATE_P4
table = devm_kcalloc(dev, AVS_PSTATE_MAX + 1, sizeof(*table),
GFP_KERNEL);
...
for (i = AVS_PSTATE_P0; i <= AVS_PSTATE_MAX; i++) {
...
}
table[i].frequency = CPUFREQ_TABLE_END;
I see "AVS_PSTATE_MAX + 1" being used for the allocation, and so the
loop is likely correctly doing P0 through P4. If there is supposed to be
a terminating element in the table, I think the correct fix would be to
allocate an additional element, not stop the loop from processing P4.
> [...]
> - for (i = AVS_PSTATE_P0; i <= AVS_PSTATE_MAX; i++) {
> + for (i = AVS_PSTATE_P0; i < AVS_PSTATE_MAX; i++) {
> ret = brcm_avs_set_pstate(priv, i);
> if (ret)
> return ERR_PTR(ret);
-Kees
--
Kees Cook
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-07-31 23:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-31 21:07 [PATCH v2] cpufreq: brcmstb-avs-cpufreq: Fix -Warray-bounds bug Gustavo A. R. Silva
2023-07-31 23:16 ` Kees Cook [this message]
2023-08-01 3:20 ` Gustavo A. R. Silva
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=202307311610.B1EB796684@keescook \
--to=keescook@chromium.org \
--cc=bcm-kernel-feedback-list@broadcom.com \
--cc=florian.fainelli@broadcom.com \
--cc=gustavoars@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mmayer@broadcom.com \
--cc=rafael@kernel.org \
--cc=viresh.kumar@linaro.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;
as well as URLs for NNTP newsgroup(s).