From 2fd36558f02c0606768929fc77671716680d01c2 Mon Sep 17 00:00:00 2001 From: Johan Hedberg Date: Thu, 11 Jun 2015 13:52:26 +0300 Subject: 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: Johan Hedberg Signed-off-by: Marcel Holtmann --- net/bluetooth/smp.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 57 insertions(+), 4 deletions(-) diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c index 4bfaa3d3ed28..d0220fb76dc0 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; @@ -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. * -- cgit v1.2.3-58-ga151