Linux Power Management development
 help / color / mirror / Atom feed
From: Takashi Iwai <tiwai@suse.de>
To: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-pm@vger.kernel.org
Subject: [PATCH] cpufreq: Use scnprintf() for avoiding potential buffer overflow
Date: Wed, 11 Mar 2020 08:13:41 +0100	[thread overview]
Message-ID: <20200311071341.4339-1-tiwai@suse.de> (raw)

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().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 drivers/cpufreq/cpufreq_stats.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index f9bcf0f3ea30..94d959a8e954 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -90,35 +90,35 @@ static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
 	if (policy->fast_switch_enabled)
 		return 0;
 
-	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
-	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
+	len += scnprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
+	len += scnprintf(buf + len, PAGE_SIZE - len, "         : ");
 	for (i = 0; i < stats->state_num; i++) {
 		if (len >= PAGE_SIZE)
 			break;
-		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%9u ",
 				stats->freq_table[i]);
 	}
 	if (len >= PAGE_SIZE)
 		return PAGE_SIZE;
 
-	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
+	len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
 
 	for (i = 0; i < stats->state_num; i++) {
 		if (len >= PAGE_SIZE)
 			break;
 
-		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 				stats->freq_table[i]);
 
 		for (j = 0; j < stats->state_num; j++) {
 			if (len >= PAGE_SIZE)
 				break;
-			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
+			len += scnprintf(buf + len, PAGE_SIZE - len, "%9u ",
 					stats->trans_table[i*stats->max_state+j]);
 		}
 		if (len >= PAGE_SIZE)
 			break;
-		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
+		len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
 	}
 
 	if (len >= PAGE_SIZE) {
-- 
2.16.4


             reply	other threads:[~2020-03-11  7:13 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11  7:13 Takashi Iwai [this message]
2020-03-11  7:14 ` [PATCH] cpufreq: Use scnprintf() for avoiding potential buffer overflow Viresh Kumar

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=20200311071341.4339-1-tiwai@suse.de \
    --to=tiwai@suse.de \
    --cc=linux-pm@vger.kernel.org \
    --cc=rjw@rjwysocki.net \
    --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