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| author | Guenter Roeck <linux@roeck-us.net> | 2017-07-11 20:53:55 -0700 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2017-07-15 16:38:56 -0700 |
| commit | 1009ccdc64ee2c8451f76b548589f6b989d13412 (patch) | |
| tree | 1550e7c64fa36ed378ae26a874d9a694027d4d5a /drivers/hwmon/applesmc.c | |
| parent | 5771a8c08880cdca3bfb4a3fc6d309d6bba20877 (diff) | |
| download | linux-1009ccdc64ee2c8451f76b548589f6b989d13412.tar.gz | |
hwmon: (applesmc) Avoid buffer overruns
gcc 7.1 complains that the driver uses sprintf() and thus does not validate the length of output buffers. drivers/hwmon/applesmc.c: In function 'applesmc_show_fan_position': drivers/hwmon/applesmc.c:82:21: warning: '%d' directive writing between 1 and 5 bytes into a region of size 4 Fix the problem by using scnprintf() instead of sprintf() throughout the driver. Also explicitly limit the number of supported fans to avoid actual buffer overruns and thus invalid keys. Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/applesmc.c')
| -rw-r--r-- | drivers/hwmon/applesmc.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c index 0af7fd311979..76c34f4fde13 100644 --- a/drivers/hwmon/applesmc.c +++ b/drivers/hwmon/applesmc.c @@ -566,6 +566,8 @@ static int applesmc_init_smcreg_try(void) if (ret) return ret; s->fan_count = tmp[0]; + if (s->fan_count > 10) + s->fan_count = 10; ret = applesmc_get_lower_bound(&s->temp_begin, "T"); if (ret) @@ -811,7 +813,8 @@ static ssize_t applesmc_show_fan_speed(struct device *dev, char newkey[5]; u8 buffer[2]; - sprintf(newkey, fan_speed_fmt[to_option(attr)], to_index(attr)); + scnprintf(newkey, sizeof(newkey), fan_speed_fmt[to_option(attr)], + to_index(attr)); ret = applesmc_read_key(newkey, buffer, 2); speed = ((buffer[0] << 8 | buffer[1]) >> 2); @@ -834,7 +837,8 @@ static ssize_t applesmc_store_fan_speed(struct device *dev, if (kstrtoul(sysfsbuf, 10, &speed) < 0 || speed >= 0x4000) return -EINVAL; /* Bigger than a 14-bit value */ - sprintf(newkey, fan_speed_fmt[to_option(attr)], to_index(attr)); + scnprintf(newkey, sizeof(newkey), fan_speed_fmt[to_option(attr)], + to_index(attr)); buffer[0] = (speed >> 6) & 0xff; buffer[1] = (speed << 2) & 0xff; @@ -903,7 +907,7 @@ static ssize_t applesmc_show_fan_position(struct device *dev, char newkey[5]; u8 buffer[17]; - sprintf(newkey, FAN_ID_FMT, to_index(attr)); + scnprintf(newkey, sizeof(newkey), FAN_ID_FMT, to_index(attr)); ret = applesmc_read_key(newkey, buffer, 16); buffer[16] = 0; @@ -1116,7 +1120,8 @@ static int applesmc_create_nodes(struct applesmc_node_group *groups, int num) } for (i = 0; i < num; i++) { node = &grp->nodes[i]; - sprintf(node->name, grp->format, i + 1); + scnprintf(node->name, sizeof(node->name), grp->format, + i + 1); node->sda.index = (grp->option << 16) | (i & 0xffff); node->sda.dev_attr.show = grp->show; node->sda.dev_attr.store = grp->store; |