* [PATCH] cpufreq: Use scnprintf() for avoiding potential buffer overflow
@ 2020-03-11 7:13 Takashi Iwai
2020-03-11 7:14 ` Viresh Kumar
0 siblings, 1 reply; 2+ messages in thread
From: Takashi Iwai @ 2020-03-11 7:13 UTC (permalink / raw)
To: Rafael J . Wysocki, Viresh Kumar; +Cc: linux-pm
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] cpufreq: Use scnprintf() for avoiding potential buffer overflow
2020-03-11 7:13 [PATCH] cpufreq: Use scnprintf() for avoiding potential buffer overflow Takashi Iwai
@ 2020-03-11 7:14 ` Viresh Kumar
0 siblings, 0 replies; 2+ messages in thread
From: Viresh Kumar @ 2020-03-11 7:14 UTC (permalink / raw)
To: Takashi Iwai; +Cc: Rafael J . Wysocki, linux-pm
On 11-03-20, 08:13, 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().
>
> 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) {
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
--
viresh
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