From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Date: Tue, 24 May 2022 13:02:45 -0700

Subject: Bluetooth: eir: Fix using strlen with hdev->{dev_name,short_name}

Patch-mainline: v6.0-rc1

Git-commit: dd7b8cdde098cf9f7c8de409b5b7bbb98f97be80

References: jsc#PED-1407

Both dev_name and short_name are not guaranteed to be NULL terminated so

this instead use strnlen and then attempt to determine if the resulting

string needs to be truncated or not.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216018

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Acked-by: Lee, Chun-Yi <jlee@suse.com>

---

 net/bluetooth/eir.c  |   41 ++++++++++++++++++++++++++---------------

 net/bluetooth/mgmt.c |    4 ++--

 2 files changed, 28 insertions(+), 17 deletions(-)

--- a/net/bluetooth/eir.c

+++ b/net/bluetooth/eir.c

@@ -13,6 +13,20 @@

 #define PNP_INFO_SVCLASS_ID		0x1200

+static u8 eir_append_name(u8 *eir, u16 eir_len, u8 type, u8 *data, u8 data_len)

+{

+	u8 name[HCI_MAX_SHORT_NAME_LENGTH + 1];

+

+	/* If data is already NULL terminated just pass it directly */

+	if (data[data_len - 1] == '\0')

+		return eir_append_data(eir, eir_len, type, data, data_len);

+

+	memcpy(name, data, HCI_MAX_SHORT_NAME_LENGTH);

+	name[HCI_MAX_SHORT_NAME_LENGTH] = '\0';

+

+	return eir_append_data(eir, eir_len, type, name, sizeof(name));

+}

+

 u8 eir_append_local_name(struct hci_dev *hdev, u8 *ptr, u8 ad_len)

 {

 	size_t short_len;

@@ -23,29 +37,26 @@ u8 eir_append_local_name(struct hci_dev

 		return ad_len;

 	/* use complete name if present and fits */

-	complete_len = strlen(hdev->dev_name);

+	complete_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));

 	if (complete_len && complete_len <= HCI_MAX_SHORT_NAME_LENGTH)

-		return eir_append_data(ptr, ad_len, EIR_NAME_COMPLETE,

+		return eir_append_name(ptr, ad_len, EIR_NAME_COMPLETE,

 				       hdev->dev_name, complete_len + 1);

 	/* use short name if present */

-	short_len = strlen(hdev->short_name);

+	short_len = strnlen(hdev->short_name, sizeof(hdev->short_name));

 	if (short_len)

-		return eir_append_data(ptr, ad_len, EIR_NAME_SHORT,

-				       hdev->short_name, short_len + 1);

+		return eir_append_name(ptr, ad_len, EIR_NAME_SHORT,

+				       hdev->short_name,

+				       short_len == HCI_MAX_SHORT_NAME_LENGTH ?

+				       short_len : short_len + 1);

 	/* use shortened full name if present, we already know that name

 	 * is longer then HCI_MAX_SHORT_NAME_LENGTH

 	 */

-	if (complete_len) {

-		u8 name[HCI_MAX_SHORT_NAME_LENGTH + 1];

-

-		memcpy(name, hdev->dev_name, HCI_MAX_SHORT_NAME_LENGTH);

-		name[HCI_MAX_SHORT_NAME_LENGTH] = '\0';

-

-		return eir_append_data(ptr, ad_len, EIR_NAME_SHORT, name,

-				       sizeof(name));

-	}

+	if (complete_len)

+		return eir_append_name(ptr, ad_len, EIR_NAME_SHORT,

+				       hdev->dev_name,

+				       HCI_MAX_SHORT_NAME_LENGTH);

 	return ad_len;

 }

@@ -181,7 +192,7 @@ void eir_create(struct hci_dev *hdev, u8

 	u8 *ptr = data;

 	size_t name_len;

-	name_len = strlen(hdev->dev_name);

+	name_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));

 	if (name_len > 0) {

 		/* EIR Data type */

--- a/net/bluetooth/mgmt.c

+++ b/net/bluetooth/mgmt.c

@@ -1082,11 +1082,11 @@ static u16 append_eir_data_to_buf(struct

 		eir_len = eir_append_le16(eir, eir_len, EIR_APPEARANCE,

 					  hdev->appearance);

-	name_len = strlen(hdev->dev_name);

+	name_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));

 	eir_len = eir_append_data(eir, eir_len, EIR_NAME_COMPLETE,

 				  hdev->dev_name, name_len);

-	name_len = strlen(hdev->short_name);

+	name_len = strnlen(hdev->short_name, sizeof(hdev->short_name));

 	eir_len = eir_append_data(eir, eir_len, EIR_NAME_SHORT,

 				  hdev->short_name, name_len);