From: Johan Hedberg <johan.hedberg@xxxxxxxxx>
This patch adds a debugfs control to set a different maximum SMP
encryption key size. This is useful for testing that implementation of
the encryption key size handling is behaving correctly.
Signed-off-by: Johan Hedberg <johan.hedberg@xxxxxxxxx>
---
net/bluetooth/smp.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 59 insertions(+), 6 deletions(-)
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 3921cba056d3..4d5e24ec570e 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -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;
@@ -1691,7 +1697,7 @@ static void build_bredr_pairing_cmd(struct smp_chan *smp,
req->init_key_dist = local_dist;
req->resp_key_dist = remote_dist;
- req->max_key_size = SMP_MAX_ENC_KEY_SIZE;
+ req->max_key_size = SMP_DEV(hdev)->max_key_size;
smp->remote_key_dist = remote_dist;
@@ -1700,7 +1706,7 @@ static void build_bredr_pairing_cmd(struct smp_chan *smp,
memset(rsp, 0, sizeof(*rsp));
- 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;
@@ -3123,6 +3129,7 @@ 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();
@@ -3245,6 +3252,49 @@ static const struct file_operations force_bredr_smp_fops = {
.llseek = default_llseek,
};
+static ssize_t smp_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 smp_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 smp_max_key_size_fops = {
+ .open = simple_open,
+ .read = smp_max_key_size_read,
+ .write = smp_max_key_size_write,
+ .llseek = default_llseek,
+};
+
int smp_register(struct hci_dev *hdev)
{
struct l2cap_chan *chan;
@@ -3269,6 +3319,9 @@ int smp_register(struct hci_dev *hdev)
hdev->smp_data = chan;
+ debugfs_create_file("smp_max_key_size", 0644, hdev->debugfs,
+ hdev, &smp_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.
*
--
2.4.2
--
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