2024-06-06 13:13:22

by Dan Carpenter

[permalink] [raw]
Subject: [PATCH] hwmon: (cros_ec) Prevent read overflow in probe()

The "resp.sensor_name" comes from cros_ec_cmd() and it hasn't necessarily
been NUL terminated. We had not intended to read past "sensor_name_size"
bytes, however, there is a width vs precision bug in the format string.
The format needs to be precision '%.*s' instead of width '%*s'.
Precision prevents an out of bounds read, but width is a no-op.

Fixes: bc3e45258096 ("hwmon: add ChromeOS EC driver")
Signed-off-by: Dan Carpenter <[email protected]>
---
drivers/hwmon/cros_ec_hwmon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/cros_ec_hwmon.c b/drivers/hwmon/cros_ec_hwmon.c
index 41f268fa8260..b3ba7247e06b 100644
--- a/drivers/hwmon/cros_ec_hwmon.c
+++ b/drivers/hwmon/cros_ec_hwmon.c
@@ -212,7 +212,7 @@ static void cros_ec_hwmon_probe_temp_sensors(struct device *dev, struct cros_ec_
continue;

sensor_name_size = strnlen(resp.sensor_name, sizeof(resp.sensor_name));
- priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%*s",
+ priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%.*s",
(int)sensor_name_size,
resp.sensor_name);
}
--
2.43.0



2024-06-06 14:06:13

by Guenter Roeck

[permalink] [raw]
Subject: Re: [PATCH] hwmon: (cros_ec) Prevent read overflow in probe()

On 6/6/24 06:12, Dan Carpenter wrote:
> The "resp.sensor_name" comes from cros_ec_cmd() and it hasn't necessarily
> been NUL terminated. We had not intended to read past "sensor_name_size"
> bytes, however, there is a width vs precision bug in the format string.
> The format needs to be precision '%.*s' instead of width '%*s'.
> Precision prevents an out of bounds read, but width is a no-op.
>
> Fixes: bc3e45258096 ("hwmon: add ChromeOS EC driver")
> Signed-off-by: Dan Carpenter <[email protected]>

Reviewed-by: Guenter Roeck <[email protected]>

> ---
> drivers/hwmon/cros_ec_hwmon.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hwmon/cros_ec_hwmon.c b/drivers/hwmon/cros_ec_hwmon.c
> index 41f268fa8260..b3ba7247e06b 100644
> --- a/drivers/hwmon/cros_ec_hwmon.c
> +++ b/drivers/hwmon/cros_ec_hwmon.c
> @@ -212,7 +212,7 @@ static void cros_ec_hwmon_probe_temp_sensors(struct device *dev, struct cros_ec_
> continue;
>
> sensor_name_size = strnlen(resp.sensor_name, sizeof(resp.sensor_name));
> - priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%*s",
> + priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%.*s",
> (int)sensor_name_size,
> resp.sensor_name);
> }


2024-06-06 15:14:04

by Thomas Weißschuh

[permalink] [raw]
Subject: Re: [PATCH] hwmon: (cros_ec) Prevent read overflow in probe()

Thanks!

On 2024-06-06 16:12:11+0000, Dan Carpenter wrote:
> The "resp.sensor_name" comes from cros_ec_cmd() and it hasn't necessarily
> been NUL terminated. We had not intended to read past "sensor_name_size"
> bytes, however, there is a width vs precision bug in the format string.
> The format needs to be precision '%.*s' instead of width '%*s'.
> Precision prevents an out of bounds read, but width is a no-op.
>
> Fixes: bc3e45258096 ("hwmon: add ChromeOS EC driver")
> Signed-off-by: Dan Carpenter <[email protected]>

Acked-by: Thomas Weißschuh <[email protected]>

devm_kstrndup() would have been nice.


Thomas

Subject: Re: [PATCH] hwmon: (cros_ec) Prevent read overflow in probe()

Hello:

This patch was applied to chrome-platform/linux.git (for-kernelci)
by Tzung-Bi Shih <[email protected]>:

On Thu, 6 Jun 2024 16:12:11 +0300 you wrote:
> The "resp.sensor_name" comes from cros_ec_cmd() and it hasn't necessarily
> been NUL terminated. We had not intended to read past "sensor_name_size"
> bytes, however, there is a width vs precision bug in the format string.
> The format needs to be precision '%.*s' instead of width '%*s'.
> Precision prevents an out of bounds read, but width is a no-op.
>
> Fixes: bc3e45258096 ("hwmon: add ChromeOS EC driver")
> Signed-off-by: Dan Carpenter <[email protected]>
>
> [...]

Here is the summary with links:
- hwmon: (cros_ec) Prevent read overflow in probe()
https://git.kernel.org/chrome-platform/c/1f72dd046270

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



Subject: Re: [PATCH] hwmon: (cros_ec) Prevent read overflow in probe()

Hello:

This patch was applied to chrome-platform/linux.git (for-next)
by Tzung-Bi Shih <[email protected]>:

On Thu, 6 Jun 2024 16:12:11 +0300 you wrote:
> The "resp.sensor_name" comes from cros_ec_cmd() and it hasn't necessarily
> been NUL terminated. We had not intended to read past "sensor_name_size"
> bytes, however, there is a width vs precision bug in the format string.
> The format needs to be precision '%.*s' instead of width '%*s'.
> Precision prevents an out of bounds read, but width is a no-op.
>
> Fixes: bc3e45258096 ("hwmon: add ChromeOS EC driver")
> Signed-off-by: Dan Carpenter <[email protected]>
>
> [...]

Here is the summary with links:
- hwmon: (cros_ec) Prevent read overflow in probe()
https://git.kernel.org/chrome-platform/c/1f72dd046270

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html