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author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2023-11-14 22:53:08 +0300 |
---|---|---|
committer | Guenter Roeck <linux@roeck-us.net> | 2023-12-11 17:20:28 +0300 |
commit | b0d51ada88a326e2bb58323b64879a596cd339f3 (patch) | |
tree | 53d2929365a7ca441a85501e4c718fe02e91de94 /drivers/hwmon/aspeed-pwm-tacho.c | |
parent | 10bd80e0b3160008d65c9240ca9660c596e2f269 (diff) | |
download | linux-b0d51ada88a326e2bb58323b64879a596cd339f3.tar.xz |
hwmon: (aspeed-pwm-tacho) Fix -Wstringop-overflow warning in aspeed_create_fan_tach_channel()
Based on the documentation below, the maximum number of Fan tach
channels is 16:
Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt:45:
45 - aspeed,fan-tach-ch : should specify the Fan tach input channel.
46 integer value in the range 0 through 15, with 0 indicating
47 Fan tach channel 0 and 15 indicating Fan tach channel 15.
48 At least one Fan tach input channel is required.
However, the compiler doesn't know that, and legitimaly warns about a potential
overwrite in array `u8 fan_tach_ch_source[16]` in `struct aspeed_pwm_tacho_data`,
in case `index` takes a value outside the boundaries of the array:
drivers/hwmon/aspeed-pwm-tacho.c:
179 struct aspeed_pwm_tacho_data {
...
184 bool fan_tach_present[16];
...
193 u8 fan_tach_ch_source[16];
196 };
In function ‘aspeed_create_fan_tach_channel’,
inlined from ‘aspeed_create_fan’ at drivers/hwmon/aspeed-pwm-tacho.c:877:2,
inlined from ‘aspeed_pwm_tacho_probe’ at drivers/hwmon/aspeed-pwm-tacho.c:936:9:
drivers/hwmon/aspeed-pwm-tacho.c:751:49: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
751 | priv->fan_tach_ch_source[index] = pwm_source;
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
drivers/hwmon/aspeed-pwm-tacho.c: In function ‘aspeed_pwm_tacho_probe’:
drivers/hwmon/aspeed-pwm-tacho.c:193:12: note: at offset [48, 255] into destination object ‘fan_tach_ch_source’ of size 16
193 | u8 fan_tach_ch_source[16];
| ^~~~~~~~~~~~~~~~~~
Fix this by sanity checking `index` before using it to index arrays of
size 16 elements in `struct aspeed_pwm_tacho_data`. Also, pass `dev` as
argument to function `aspeed_create_fan_tach_channel()`, and add an error
message in case `index` is out-of-bounds, in which case return `-EINVAL`.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/ZVPQJIP26dIzRAr6@work
[groeck: Fixed continuation line alignment]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/aspeed-pwm-tacho.c')
-rw-r--r-- | drivers/hwmon/aspeed-pwm-tacho.c | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c index 997df4b40509..f6e1e55e8292 100644 --- a/drivers/hwmon/aspeed-pwm-tacho.c +++ b/drivers/hwmon/aspeed-pwm-tacho.c @@ -166,6 +166,8 @@ #define MAX_CDEV_NAME_LEN 16 +#define MAX_ASPEED_FAN_TACH_CHANNELS 16 + struct aspeed_cooling_device { char name[16]; struct aspeed_pwm_tacho_data *priv; @@ -181,7 +183,7 @@ struct aspeed_pwm_tacho_data { struct reset_control *rst; unsigned long clk_freq; bool pwm_present[8]; - bool fan_tach_present[16]; + bool fan_tach_present[MAX_ASPEED_FAN_TACH_CHANNELS]; u8 type_pwm_clock_unit[3]; u8 type_pwm_clock_division_h[3]; u8 type_pwm_clock_division_l[3]; @@ -190,7 +192,7 @@ struct aspeed_pwm_tacho_data { u16 type_fan_tach_unit[3]; u8 pwm_port_type[8]; u8 pwm_port_fan_ctrl[8]; - u8 fan_tach_ch_source[16]; + u8 fan_tach_ch_source[MAX_ASPEED_FAN_TACH_CHANNELS]; struct aspeed_cooling_device *cdev[8]; const struct attribute_group *groups[3]; }; @@ -737,20 +739,27 @@ static void aspeed_create_pwm_port(struct aspeed_pwm_tacho_data *priv, aspeed_set_pwm_port_fan_ctrl(priv, pwm_port, INIT_FAN_CTRL); } -static void aspeed_create_fan_tach_channel(struct aspeed_pwm_tacho_data *priv, - u8 *fan_tach_ch, - int count, - u8 pwm_source) +static int aspeed_create_fan_tach_channel(struct device *dev, + struct aspeed_pwm_tacho_data *priv, + u8 *fan_tach_ch, + int count, + u8 pwm_source) { u8 val, index; for (val = 0; val < count; val++) { index = fan_tach_ch[val]; + if (index >= MAX_ASPEED_FAN_TACH_CHANNELS) { + dev_err(dev, "Invalid Fan Tach input channel %u\n.", index); + return -EINVAL; + } aspeed_set_fan_tach_ch_enable(priv->regmap, index, true); priv->fan_tach_present[index] = true; priv->fan_tach_ch_source[index] = pwm_source; aspeed_set_fan_tach_ch_source(priv->regmap, index, pwm_source); } + + return 0; } static int @@ -874,7 +883,10 @@ static int aspeed_create_fan(struct device *dev, fan_tach_ch, count); if (ret) return ret; - aspeed_create_fan_tach_channel(priv, fan_tach_ch, count, pwm_port); + + ret = aspeed_create_fan_tach_channel(dev, priv, fan_tach_ch, count, pwm_port); + if (ret) + return ret; return 0; } |