[PATCH] platform/chrome: cros_ec_chardev: fix kernel data leak from ioctl

[PATCH] platform/chrome: cros_ec_chardev: fix kernel data leak from ioctl

[Tzung-Bi Shih]

It is possible to peep kernel page's data by providing larger `insize`
in struct cros_ec_command[1] when invoking EC host commands.

Fix it by using zeroed memory.

[1]: https://elixir.bootlin.com/linux/v6.2/source/include/linux/platform_data/cros_ec_proto.h#L74

Fixes: eda2e30c6684 ("mfd / platform: cros_ec: Miscellaneous character device to talk with the EC")
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
 drivers/platform/chrome/cros_ec_chardev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/chrome/cros_ec_chardev.c b/drivers/platform/chrome/cros_ec_chardev.c
index 0de7c255254e..d6de5a294128 100644
--- a/drivers/platform/chrome/cros_ec_chardev.c
+++ b/drivers/platform/chrome/cros_ec_chardev.c
@@ -284,7 +284,7 @@ static long cros_ec_chardev_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
 	    u_cmd.insize > EC_MAX_MSG_BYTES)
 		return -EINVAL;
 
-	s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
+	s_cmd = kzalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
 			GFP_KERNEL);
 	if (!s_cmd)
 		return -ENOMEM;
-- 
2.40.0.348.gf938b09366-goog

Re: [PATCH] platform/chrome: cros_ec_chardev: fix kernel data leak from ioctl

[Guenter Roeck]

On Thu, Mar 23, 2023 at 6:07 PM Tzung-Bi Shih <tzungbi@kernel.org> wrote:
>
> It is possible to peep kernel page's data by providing larger `insize`
> in struct cros_ec_command[1] when invoking EC host commands.
>
> Fix it by using zeroed memory.
>
> [1]: https://elixir.bootlin.com/linux/v6.2/source/include/linux/platform_data/cros_ec_proto.h#L74
>
> Fixes: eda2e30c6684 ("mfd / platform: cros_ec: Miscellaneous character device to talk with the EC")
> Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

Reviewed-by: Guenter Roeck <groeck@chromium.org>

> ---
>  drivers/platform/chrome/cros_ec_chardev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_chardev.c b/drivers/platform/chrome/cros_ec_chardev.c
> index 0de7c255254e..d6de5a294128 100644
> --- a/drivers/platform/chrome/cros_ec_chardev.c
> +++ b/drivers/platform/chrome/cros_ec_chardev.c
> @@ -284,7 +284,7 @@ static long cros_ec_chardev_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
>             u_cmd.insize > EC_MAX_MSG_BYTES)
>                 return -EINVAL;
>
> -       s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
> +       s_cmd = kzalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
>                         GFP_KERNEL);
>         if (!s_cmd)
>                 return -ENOMEM;
> --
> 2.40.0.348.gf938b09366-goog
>

Re: [PATCH] platform/chrome: cros_ec_chardev: fix kernel data leak from ioctl

[patchwork-bot+chrome-platform]

Hello:

This patch was applied to chrome-platform/linux.git (for-kernelci)
by Tzung-Bi Shih <tzungbi@kernel.org>:

On Fri, 24 Mar 2023 09:06:58 +0800 you wrote:
> It is possible to peep kernel page's data by providing larger `insize`
> in struct cros_ec_command[1] when invoking EC host commands.
> 
> Fix it by using zeroed memory.
> 
> [1]: https://elixir.bootlin.com/linux/v6.2/source/include/linux/platform_data/cros_ec_proto.h#L74
> 
> [...]

Here is the summary with links:
  - platform/chrome: cros_ec_chardev: fix kernel data leak from ioctl
    https://git.kernel.org/chrome-platform/c/b20cf3f89c56

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

Re: [PATCH] platform/chrome: cros_ec_chardev: fix kernel data leak from ioctl

[patchwork-bot+chrome-platform]

Hello:

This patch was applied to chrome-platform/linux.git (for-next)
by Tzung-Bi Shih <tzungbi@kernel.org>:

On Fri, 24 Mar 2023 09:06:58 +0800 you wrote:
> It is possible to peep kernel page's data by providing larger `insize`
> in struct cros_ec_command[1] when invoking EC host commands.
> 
> Fix it by using zeroed memory.
> 
> [1]: https://elixir.bootlin.com/linux/v6.2/source/include/linux/platform_data/cros_ec_proto.h#L74
> 
> [...]

Here is the summary with links:
  - platform/chrome: cros_ec_chardev: fix kernel data leak from ioctl
    https://git.kernel.org/chrome-platform/c/b20cf3f89c56

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