From 949fe25f2ad31f72572dcad491843d355dc93b32 Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai@suse.de> Date: Wed, 11 Mar 2020 08:08:51 +0100 Subject: [PATCH] ACPI: fan: Use scnprintf() for avoiding potential buffer overflow 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> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> --- 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 aaf4e8f348cf3..873e039ad4b70 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; } -- GitLab