From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Takashi Iwai <tiwai@suse.de>
Cc: linux-acpi@vger.kernel.org, Zhang Rui <rui.zhang@intel.com>,
Len Brown <lenb@kernel.org>
Subject: Re: [PATCH] ACPI: fan: Use scnprintf() for avoiding potential buffer overflow
Date: Sat, 14 Mar 2020 11:13:55 +0100 [thread overview]
Message-ID: <6805885.HkWLXbPDYh@kreacher> (raw)
In-Reply-To: <20200311070851.3731-1-tiwai@suse.de>
On Wednesday, March 11, 2020 8:08:51 AM CET Takashi Iwai wrote:
> Since snprintf() returns the would-be-output size instead of the
> actual output size, the succeeding calls may go beyond the given
> buffer limit. Fix it by replacing with scnprintf().
>
> Also adjust the argument to really match with the actually remaining
> buffer size.
>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
> drivers/acpi/fan.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/acpi/fan.c b/drivers/acpi/fan.c
> index aaf4e8f348cf..873e039ad4b7 100644
> --- a/drivers/acpi/fan.c
> +++ b/drivers/acpi/fan.c
> @@ -276,29 +276,29 @@ static ssize_t show_state(struct device *dev, struct device_attribute *attr, cha
> int count;
>
> if (fps->control == 0xFFFFFFFF || fps->control > 100)
> - count = snprintf(buf, PAGE_SIZE, "not-defined:");
> + count = scnprintf(buf, PAGE_SIZE, "not-defined:");
> else
> - count = snprintf(buf, PAGE_SIZE, "%lld:", fps->control);
> + count = scnprintf(buf, PAGE_SIZE, "%lld:", fps->control);
>
> if (fps->trip_point == 0xFFFFFFFF || fps->trip_point > 9)
> - count += snprintf(&buf[count], PAGE_SIZE, "not-defined:");
> + count += scnprintf(&buf[count], PAGE_SIZE - count, "not-defined:");
> else
> - count += snprintf(&buf[count], PAGE_SIZE, "%lld:", fps->trip_point);
> + count += scnprintf(&buf[count], PAGE_SIZE - count, "%lld:", fps->trip_point);
>
> if (fps->speed == 0xFFFFFFFF)
> - count += snprintf(&buf[count], PAGE_SIZE, "not-defined:");
> + count += scnprintf(&buf[count], PAGE_SIZE - count, "not-defined:");
> else
> - count += snprintf(&buf[count], PAGE_SIZE, "%lld:", fps->speed);
> + count += scnprintf(&buf[count], PAGE_SIZE - count, "%lld:", fps->speed);
>
> if (fps->noise_level == 0xFFFFFFFF)
> - count += snprintf(&buf[count], PAGE_SIZE, "not-defined:");
> + count += scnprintf(&buf[count], PAGE_SIZE - count, "not-defined:");
> else
> - count += snprintf(&buf[count], PAGE_SIZE, "%lld:", fps->noise_level * 100);
> + count += scnprintf(&buf[count], PAGE_SIZE - count, "%lld:", fps->noise_level * 100);
>
> if (fps->power == 0xFFFFFFFF)
> - count += snprintf(&buf[count], PAGE_SIZE, "not-defined\n");
> + count += scnprintf(&buf[count], PAGE_SIZE - count, "not-defined\n");
> else
> - count += snprintf(&buf[count], PAGE_SIZE, "%lld\n", fps->power);
> + count += scnprintf(&buf[count], PAGE_SIZE - count, "%lld\n", fps->power);
>
> return count;
> }
>
Applied as 5.7 material, thanks!
prev parent reply other threads:[~2020-03-15 2:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 7:08 [PATCH] ACPI: fan: Use scnprintf() for avoiding potential buffer overflow Takashi Iwai
2020-03-14 10:13 ` Rafael J. Wysocki [this message]
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