On Tue, Mar 18, 2025 at 08:33:20PM +1030, Gustavo A. R. Silva wrote:
> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
>
> Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of
> a flexible structure where the size of the flexible-array member
> is known at compile-time, and refactor the rest of the code,
> accordingly.
>
> So, with these changes, fix the following warning:
>
> drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c:39:40: warning:
> structure containing a flexible array member is not at the end of another
> structure [-Wflex-array-member-not-at-end]
>
> Signed-off-by: Gustavo A. R. Silva <gustavo...@kernel.org>
> ---
> Changes in v2:
> - Use MAX() to calculate the number of bytes for the flex array. (Kees)
>
> v1:
> - Link: https://lore.kernel.org/linux-hardening/Z9dy43vUUh4goi-Q@kspp/
>
> .../cros_ec_sensors/cros_ec_sensors_core.c | 28 ++++++++-----------
> 1 file changed, 11 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> index 7751d6f69b12..40d5b10c74e0 100644
> --- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> @@ -34,25 +34,19 @@
> static int cros_ec_get_host_cmd_version_mask(struct cros_ec_device *ec_dev,
> u16 cmd_offset, u16 cmd, u32 *mask)
> {
> + DEFINE_RAW_FLEX(struct cros_ec_command, buf, data,
> + MAX(sizeof(struct ec_response_get_cmd_versions),
> + sizeof(struct ec_params_get_cmd_versions)));
> int ret;
> - struct {
> - struct cros_ec_command msg;
> - union {
> - struct ec_params_get_cmd_versions params;
> - struct ec_response_get_cmd_versions resp;
> - };
> - } __packed buf = {
> - .msg = {
> - .command = EC_CMD_GET_CMD_VERSIONS + cmd_offset,
> - .insize = sizeof(struct ec_response_get_cmd_versions),
> - .outsize = sizeof(struct ec_params_get_cmd_versions)
> - },
> - .params = {.cmd = cmd}
> - };
> -
> - ret = cros_ec_cmd_xfer_status(ec_dev, &buf.msg);
> +
> + buf->command = EC_CMD_GET_CMD_VERSIONS + cmd_offset;
> + buf->insize = sizeof(struct ec_response_get_cmd_versions);
> + buf->outsize = sizeof(struct ec_params_get_cmd_versions);
> + ((struct ec_params_get_cmd_versions *)buf->data)->cmd = cmd;
> +
> + ret = cros_ec_cmd_xfer_status(ec_dev, buf);
> if (ret >= 0)
> - *mask = buf.resp.version_mask;
> + *mask = ((struct ec_response_get_cmd_versions
> *)buf->data)->version_mask;
> return ret;
> }
Since "params" is used twice, I'd say do like the other patch and assign
it to a new variable:
struct ec_response_get_cmd_versions *params = buf->data;
...
params->cmd = cmd;
...
*mask = params->version_mask;
>
> --
> 2.43.0
>
--
Kees Cook
