Commit 3b81d8bd authored by Nick Crews's avatar Nick Crews Committed by Enric Balletbo i Serra
Browse files

platform/chrome: wilco_ec: Add batt_ppid_info command to telemetry driver 



Add the GET_BATT_PPID_INFO=0x8A command to the allowlist of accepted
telemetry commands. In addition, since this new command requires
verifying the contents of some of the arguments, I also restructure
the request to use a union of the argument structs. Also, zero out the
request buffer before each request, and change "whitelist" to
"allowlist".

Signed-off-by: default avatarNick Crews <ncrews@chromium.org>
Signed-off-by: default avatarEnric Balletbo i Serra <enric.balletbo@collabora.com>
parent 5f9e832c

drivers/platform/chrome/wilco_ec/telemetry.c

+43 −21
Original line number Diff line number Diff line
@@ -9,7 +9,7 @@ 
 * the OS sends a command to the EC via a write() to a char device,

 * and can read the response with a read(). The write() request is

 * verified by the driver to ensure that it is performing only one

 * of the whitelisted commands, and that no extraneous data is

 * of the allowlisted commands, and that no extraneous data is

 * being transmitted to the EC. The response is passed directly

 * back to the reader with no modification.

 *
@@ -59,21 +59,10 @@ static DEFINE_IDA(telem_ida); 
#define WILCO_EC_TELEM_GET_TEMP_INFO		0x95

#define WILCO_EC_TELEM_GET_TEMP_READ		0x2C

#define WILCO_EC_TELEM_GET_BATT_EXT_INFO	0x07

#define WILCO_EC_TELEM_GET_BATT_PPID_INFO	0x8A



#define TELEM_ARGS_SIZE_MAX	30



/**

 * struct wilco_ec_telem_request - Telemetry command and arguments sent to EC.

 * @command: One of WILCO_EC_TELEM_GET_* command codes.

 * @reserved: Must be 0.

 * @args: The first N bytes are one of telem_args_get_* structs, the rest is 0.

 */

struct wilco_ec_telem_request {

	u8 command;

	u8 reserved;

	u8 args[TELEM_ARGS_SIZE_MAX];

} __packed;



/*

 * The following telem_args_get_* structs are embedded within the |args| field

 * of wilco_ec_telem_request.
@@ -122,6 +111,32 @@ struct telem_args_get_batt_ext_info { 
	u8 var_args[5];

} __packed;



struct telem_args_get_batt_ppid_info {

	u8 always1; /* Should always be 1 */

} __packed;



/**

 * struct wilco_ec_telem_request - Telemetry command and arguments sent to EC.

 * @command: One of WILCO_EC_TELEM_GET_* command codes.

 * @reserved: Must be 0.

 * @args: The first N bytes are one of telem_args_get_* structs, the rest is 0.

 */

struct wilco_ec_telem_request {

	u8 command;

	u8 reserved;

	union {

		u8 buf[TELEM_ARGS_SIZE_MAX];

		struct telem_args_get_log		get_log;

		struct telem_args_get_version		get_version;

		struct telem_args_get_fan_info		get_fan_info;

		struct telem_args_get_diag_info		get_diag_info;

		struct telem_args_get_temp_info		get_temp_info;

		struct telem_args_get_temp_read		get_temp_read;

		struct telem_args_get_batt_ext_info	get_batt_ext_info;

		struct telem_args_get_batt_ppid_info	get_batt_ppid_info;

	} args;

} __packed;



/**

 * check_telem_request() - Ensure that a request from userspace is valid.

 * @rq: Request buffer copied from userspace.
@@ -133,7 +148,7 @@ struct telem_args_get_batt_ext_info { 
 * We do not want to allow userspace to send arbitrary telemetry commands to

 * the EC. Therefore we check to ensure that

 * 1. The request follows the format of struct wilco_ec_telem_request.

 * 2. The supplied command code is one of the whitelisted commands.

 * 2. The supplied command code is one of the allowlisted commands.

 * 3. The request only contains the necessary data for the header and arguments.

 */

static int check_telem_request(struct wilco_ec_telem_request *rq,
@@ -146,25 +161,31 @@ static int check_telem_request(struct wilco_ec_telem_request *rq, 


	switch (rq->command) {

	case WILCO_EC_TELEM_GET_LOG:

		max_size += sizeof(struct telem_args_get_log);

		max_size += sizeof(rq->args.get_log);

		break;

	case WILCO_EC_TELEM_GET_VERSION:

		max_size += sizeof(struct telem_args_get_version);

		max_size += sizeof(rq->args.get_version);

		break;

	case WILCO_EC_TELEM_GET_FAN_INFO:

		max_size += sizeof(struct telem_args_get_fan_info);

		max_size += sizeof(rq->args.get_fan_info);

		break;

	case WILCO_EC_TELEM_GET_DIAG_INFO:

		max_size += sizeof(struct telem_args_get_diag_info);

		max_size += sizeof(rq->args.get_diag_info);

		break;

	case WILCO_EC_TELEM_GET_TEMP_INFO:

		max_size += sizeof(struct telem_args_get_temp_info);

		max_size += sizeof(rq->args.get_temp_info);

		break;

	case WILCO_EC_TELEM_GET_TEMP_READ:

		max_size += sizeof(struct telem_args_get_temp_read);

		max_size += sizeof(rq->args.get_temp_read);

		break;

	case WILCO_EC_TELEM_GET_BATT_EXT_INFO:

		max_size += sizeof(struct telem_args_get_batt_ext_info);

		max_size += sizeof(rq->args.get_batt_ext_info);

		break;

	case WILCO_EC_TELEM_GET_BATT_PPID_INFO:

		if (rq->args.get_batt_ppid_info.always1 != 1)

			return -EINVAL;



		max_size += sizeof(rq->args.get_batt_ppid_info);

		break;

	default:

		return -EINVAL;
@@ -250,6 +271,7 @@ static ssize_t telem_write(struct file *filp, const char __user *buf, 


	if (count > sizeof(sess_data->request))

		return -EMSGSIZE;

	memset(&sess_data->request, 0, sizeof(sess_data->request));

	if (copy_from_user(&sess_data->request, buf, count))

		return -EFAULT;

	ret = check_telem_request(&sess_data->request, count);

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