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Commit 2fd36558 authored by Johan Hedberg's avatar Johan Hedberg Committed by Marcel Holtmann
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Bluetooth: Add debugfs support for max LE encryption key size 



This patch adds a debugfs control to set a different maximum LE
encryption key size. This is useful for testing that implementation of
the encryption key size handling is behaving correctly.

Signed-off-by: default avatarJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 835a6a2f

net/bluetooth/smp.c

+57 −4
Original line number Diff line number Diff line
@@ -33,6 +33,9 @@ 
#include "ecc.h"

#include "smp.h"



#define SMP_DEV(hdev) \

	((struct smp_dev *)((struct l2cap_chan *)((hdev)->smp_data))->data)



/* Low-level debug macros to be used for stuff that we don't want

 * accidentially in dmesg, i.e. the values of the various crypto keys

 * and the inputs & outputs of crypto functions.
@@ -81,6 +84,8 @@ struct smp_dev { 
	u8			local_rand[16];

	bool			debug_key;



	u8			max_key_size;



	struct crypto_blkcipher	*tfm_aes;

	struct crypto_hash	*tfm_cmac;

};
@@ -708,7 +713,7 @@ static void build_pairing_cmd(struct l2cap_conn *conn, 
	if (rsp == NULL) {

		req->io_capability = conn->hcon->io_capability;

		req->oob_flag = oob_flag;

		req->max_key_size = SMP_MAX_ENC_KEY_SIZE;

		req->max_key_size = SMP_DEV(hdev)->max_key_size;

		req->init_key_dist = local_dist;

		req->resp_key_dist = remote_dist;

		req->auth_req = (authreq & AUTH_REQ_MASK(hdev));
@@ -719,7 +724,7 @@ static void build_pairing_cmd(struct l2cap_conn *conn, 


	rsp->io_capability = conn->hcon->io_capability;

	rsp->oob_flag = oob_flag;

	rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE;

	rsp->max_key_size = SMP_DEV(hdev)->max_key_size;

	rsp->init_key_dist = req->init_key_dist & remote_dist;

	rsp->resp_key_dist = req->resp_key_dist & local_dist;

	rsp->auth_req = (authreq & AUTH_REQ_MASK(hdev));
@@ -730,10 +735,11 @@ static void build_pairing_cmd(struct l2cap_conn *conn, 
static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size)

{

	struct l2cap_chan *chan = conn->smp;

	struct hci_dev *hdev = conn->hcon->hdev;

	struct smp_chan *smp = chan->data;



	if ((max_key_size > SMP_MAX_ENC_KEY_SIZE) ||

	    (max_key_size < SMP_MIN_ENC_KEY_SIZE))

	if (max_key_size > SMP_DEV(hdev)->max_key_size ||

	    max_key_size < SMP_MIN_ENC_KEY_SIZE)

		return SMP_ENC_KEY_SIZE;



	smp->enc_key_size = max_key_size;
@@ -3130,6 +3136,7 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid) 


	smp->tfm_aes = tfm_aes;

	smp->tfm_cmac = tfm_cmac;

	smp->max_key_size = SMP_MAX_ENC_KEY_SIZE;



create_chan:

	chan = l2cap_chan_create();
@@ -3252,6 +3259,49 @@ static const struct file_operations force_bredr_smp_fops = { 
	.llseek		= default_llseek,

};



static ssize_t le_max_key_size_read(struct file *file,

				     char __user *user_buf,

				     size_t count, loff_t *ppos)

{

	struct hci_dev *hdev = file->private_data;

	char buf[4];



	snprintf(buf, sizeof(buf), "%2u\n", SMP_DEV(hdev)->max_key_size);



	return simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));

}



static ssize_t le_max_key_size_write(struct file *file,

				      const char __user *user_buf,

				      size_t count, loff_t *ppos)

{

	struct hci_dev *hdev = file->private_data;

	char buf[32];

	size_t buf_size = min(count, (sizeof(buf) - 1));

	u8 key_size;



	if (copy_from_user(buf, user_buf, buf_size))

		return -EFAULT;



	buf[buf_size] = '\0';



	sscanf(buf, "%hhu", &key_size);



	if (key_size > SMP_MAX_ENC_KEY_SIZE || key_size < SMP_MIN_ENC_KEY_SIZE)

		return -EINVAL;



	SMP_DEV(hdev)->max_key_size = key_size;



	return count;

}



static const struct file_operations le_max_key_size_fops = {

	.open		= simple_open,

	.read		= le_max_key_size_read,

	.write		= le_max_key_size_write,

	.llseek		= default_llseek,

};



int smp_register(struct hci_dev *hdev)

{

	struct l2cap_chan *chan;
@@ -3276,6 +3326,9 @@ int smp_register(struct hci_dev *hdev) 


	hdev->smp_data = chan;



	debugfs_create_file("le_max_key_size", 0644, hdev->debugfs, hdev,

			    &le_max_key_size_fops);



	/* If the controller does not support BR/EDR Secure Connections

	 * feature, then the BR/EDR SMP channel shall not be present.

	 *