Patchwork [7/9] crypto: atmel-ecc: Print out serial number

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Submitter Linus Walleij
Date June 5, 2018, 1:49 p.m.
Message ID <20180605134950.6605-7-linus.walleij@linaro.org>
Download mbox | patch
Permalink /patch/10448339/
State Changes Requested
Delegated to: Herbert Xu
Headers show

Comments

Linus Walleij - June 5, 2018, 1:49 p.m.
This reads out the serial number of the crypto chip and prints it,
also toss this into the entropy pool as it is device-unique data.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/crypto/atmel-ecc.c | 56 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
Tudor-Dan Ambarus - June 12, 2018, 1:13 p.m.
Hi, Linus,

On 06/05/2018 04:49 PM, Linus Walleij wrote:
> This reads out the serial number of the crypto chip and prints it,
> also toss this into the entropy pool as it is device-unique data.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>   drivers/crypto/atmel-ecc.c | 56 ++++++++++++++++++++++++++++++++++++++
>   1 file changed, 56 insertions(+)
> 
> diff --git a/drivers/crypto/atmel-ecc.c b/drivers/crypto/atmel-ecc.c
> index 603e29bdcb97..fd8149313104 100644
> --- a/drivers/crypto/atmel-ecc.c
> +++ b/drivers/crypto/atmel-ecc.c
> @@ -29,6 +29,7 @@
>   #include <linux/scatterlist.h>
>   #include <linux/slab.h>
>   #include <linux/workqueue.h>
> +#include <linux/random.h>

includes should be ordered alphabetically.

>   #include <crypto/internal/kpp.h>
>   #include <crypto/ecdh.h>
>   #include <crypto/kpp.h>
> @@ -616,6 +617,57 @@ static inline size_t atmel_ecc_wake_token_sz(u32 bus_clk_rate)
>   	return DIV_ROUND_UP(no_of_bits, 8);
>   }
>   
> +static int atmel_ecc_get_serial(struct i2c_client *client)
> +{
> +	struct atmel_ecc_cmd *cmd;
> +	u8 serial[9];

int i, ret; before serial to avoid stack padding.

> +	int ret;
> +	int i;
> +
> +	cmd = kmalloc(sizeof(*cmd), GFP_KERNEL);
> +	if (!cmd)
> +		return -ENOMEM;
> +
> +	atmel_ecc_init_read_config_word(cmd, CONFIG_ZONE_SERIAL_0_3);
> +	ret = atmel_ecc_send_receive(client, cmd);
> +	if (ret) {

free(cmd);

> +		dev_err(&client->dev,
> +			"failed to read serial byte 0-3\n");
> +		return ret;
> +	}
> +	for (i = 0; i < 4; i++)
> +		serial[0+i] = cmd->data[RSP_DATA_IDX + i];

serial[i]?

> +
> +	atmel_ecc_init_read_config_word(cmd, CONFIG_ZONE_SERIAL_4_7);

can't we read the serial_no once?

> +	ret = atmel_ecc_send_receive(client, cmd);
> +	if (ret) {
> +		dev_err(&client->dev,
> +			"failed to read serial byte 4-7\n");
> +		return ret;
> +	}
> +	for (i = 0; i < 4; i++)
> +		serial[4+i] = cmd->data[RSP_DATA_IDX + i];

spaces preferred around that '+'

> +
> +
> +	atmel_ecc_init_read_config_word(cmd, CONFIG_ZONE_SERIAL_8_I2CEN);
> +	ret = atmel_ecc_send_receive(client, cmd);
> +	if (ret) {
> +		dev_err(&client->dev,
> +			"failed to read serial byte 8\n");
> +		return ret;
> +	}
> +	serial[8] = cmd->data[RSP_DATA_IDX];
> +
> +	/* This is device-unique data so it goes into the entropy pool */
> +	add_device_randomness(serial, sizeof(serial));
> +
> +	dev_info(&client->dev,
> +		 "serial number: %02x%02x%02x%02x%02x%02x%02x%02x%02x\n",
> +		 serial[0], serial[1], serial[2], serial[3], serial[4],
> +		 serial[5], serial[6], serial[7], serial[8]);

Why do you need the serial number printed out?

> +	return 0;
> +}
> +
>   static int device_sanity_check(struct i2c_client *client)
>   {
>   	struct atmel_ecc_cmd *cmd;
> @@ -700,6 +752,10 @@ static int atmel_ecc_probe(struct i2c_client *client,
>   	if (ret)
>   		return ret;
>   
> +	ret = atmel_ecc_get_serial(client);
> +	if (ret)
> +		return ret;
> +
>   	spin_lock(&driver_data.i2c_list_lock);
>   	list_add_tail(&i2c_priv->i2c_client_list_node,
>   		      &driver_data.i2c_client_list);
>

Patch

diff --git a/drivers/crypto/atmel-ecc.c b/drivers/crypto/atmel-ecc.c
index 603e29bdcb97..fd8149313104 100644
--- a/drivers/crypto/atmel-ecc.c
+++ b/drivers/crypto/atmel-ecc.c
@@ -29,6 +29,7 @@ 
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
+#include <linux/random.h>
 #include <crypto/internal/kpp.h>
 #include <crypto/ecdh.h>
 #include <crypto/kpp.h>
@@ -616,6 +617,57 @@  static inline size_t atmel_ecc_wake_token_sz(u32 bus_clk_rate)
 	return DIV_ROUND_UP(no_of_bits, 8);
 }
 
+static int atmel_ecc_get_serial(struct i2c_client *client)
+{
+	struct atmel_ecc_cmd *cmd;
+	u8 serial[9];
+	int ret;
+	int i;
+
+	cmd = kmalloc(sizeof(*cmd), GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	atmel_ecc_init_read_config_word(cmd, CONFIG_ZONE_SERIAL_0_3);
+	ret = atmel_ecc_send_receive(client, cmd);
+	if (ret) {
+		dev_err(&client->dev,
+			"failed to read serial byte 0-3\n");
+		return ret;
+	}
+	for (i = 0; i < 4; i++)
+		serial[0+i] = cmd->data[RSP_DATA_IDX + i];
+
+	atmel_ecc_init_read_config_word(cmd, CONFIG_ZONE_SERIAL_4_7);
+	ret = atmel_ecc_send_receive(client, cmd);
+	if (ret) {
+		dev_err(&client->dev,
+			"failed to read serial byte 4-7\n");
+		return ret;
+	}
+	for (i = 0; i < 4; i++)
+		serial[4+i] = cmd->data[RSP_DATA_IDX + i];
+
+
+	atmel_ecc_init_read_config_word(cmd, CONFIG_ZONE_SERIAL_8_I2CEN);
+	ret = atmel_ecc_send_receive(client, cmd);
+	if (ret) {
+		dev_err(&client->dev,
+			"failed to read serial byte 8\n");
+		return ret;
+	}
+	serial[8] = cmd->data[RSP_DATA_IDX];
+
+	/* This is device-unique data so it goes into the entropy pool */
+	add_device_randomness(serial, sizeof(serial));
+
+	dev_info(&client->dev,
+		 "serial number: %02x%02x%02x%02x%02x%02x%02x%02x%02x\n",
+		 serial[0], serial[1], serial[2], serial[3], serial[4],
+		 serial[5], serial[6], serial[7], serial[8]);
+	return 0;
+}
+
 static int device_sanity_check(struct i2c_client *client)
 {
 	struct atmel_ecc_cmd *cmd;
@@ -700,6 +752,10 @@  static int atmel_ecc_probe(struct i2c_client *client,
 	if (ret)
 		return ret;
 
+	ret = atmel_ecc_get_serial(client);
+	if (ret)
+		return ret;
+
 	spin_lock(&driver_data.i2c_list_lock);
 	list_add_tail(&i2c_priv->i2c_client_list_node,
 		      &driver_data.i2c_client_list);