1 files changed, 50 insertions, 1 deletions

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index d0220fb76dc0..d9ed5e8ee6a0 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -84,6 +84,7 @@ struct smp_dev {
 	u8			local_rand[16];
 	bool			debug_key;
 
+	u8			min_key_size;
 	u8			max_key_size;
 
 	struct crypto_blkcipher	*tfm_aes;
@@ -3136,6 +3137,7 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid)
 
 	smp->tfm_aes = tfm_aes;
 	smp->tfm_cmac = tfm_cmac;
+	smp->min_key_size = SMP_MIN_ENC_KEY_SIZE;
 	smp->max_key_size = SMP_MAX_ENC_KEY_SIZE;
 
 create_chan:
@@ -3259,6 +3261,50 @@ static const struct file_operations force_bredr_smp_fops = {
 	.llseek		= default_llseek,
 };
 
+static ssize_t le_min_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)->min_key_size);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
+}
+
+static ssize_t le_min_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_DEV(hdev)->max_key_size ||
+	    key_size < SMP_MIN_ENC_KEY_SIZE)
+		return -EINVAL;
+
+	SMP_DEV(hdev)->min_key_size = key_size;
+
+	return count;
+}
+
+static const struct file_operations le_min_key_size_fops = {
+	.open		= simple_open,
+	.read		= le_min_key_size_read,
+	.write		= le_min_key_size_write,
+	.llseek		= default_llseek,
+};
+
 static ssize_t le_max_key_size_read(struct file *file,
 				     char __user *user_buf,
 				     size_t count, loff_t *ppos)
@@ -3287,7 +3333,8 @@ static ssize_t le_max_key_size_write(struct file *file,
 
 	sscanf(buf, "%hhu", &key_size);
 
-	if (key_size > SMP_MAX_ENC_KEY_SIZE || key_size < SMP_MIN_ENC_KEY_SIZE)
+	if (key_size > SMP_MAX_ENC_KEY_SIZE ||
+	    key_size < SMP_DEV(hdev)->min_key_size)
 		return -EINVAL;
 
 	SMP_DEV(hdev)->max_key_size = key_size;
@@ -3326,6 +3373,8 @@ int smp_register(struct hci_dev *hdev)
 
 	hdev->smp_data = chan;
 
+	debugfs_create_file("le_min_key_size", 0644, hdev->debugfs, hdev,
+			    &le_min_key_size_fops);
 	debugfs_create_file("le_max_key_size", 0644, hdev->debugfs, hdev,
 			    &le_max_key_size_fops);