[PATCH 6.8 333/715] Bluetooth: Fix eir name length

Sasha Levin
2024-03-24T22:40:25Z

From: Frédéric Danis <frederic.danis@collabora.com>

[ Upstream commit 2ab3e8d67fc1d4a7638b769cf83023ec209fc0a9 ]

According to Section 1.2 of Core Specification Supplement Part A the
complete or short name strings are defined as utf8s, which should not
include the trailing NULL for variable length array as defined in Core
Specification Vol1 Part E Section 2.9.3.

Removing the trailing NULL allows PTS to retrieve the random address based
on device name, e.g. for SM/PER/KDU/BV-02-C, SM/PER/KDU/BV-08-C or
GAP/BROB/BCST/BV-03-C.

Fixes: f61851f64b17 ("Bluetooth: Fix append max 11 bytes of name to scan rsp data")
Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/bluetooth/eir.c | 29 +++++++----------------------
net/bluetooth/mgmt.c | 2 +-
2 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/net/bluetooth/eir.c b/net/bluetooth/eir.c
index 9214189279e80..1bc51e2b05a34 100644
--- a/net/bluetooth/eir.c
+++ b/net/bluetooth/eir.c
@@ -13,48 +13,33 @@

#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;
size_t complete_len;

- /* no space left for name (+ NULL + type + len) */
- if ((max_adv_len(hdev) - ad_len) < HCI_MAX_SHORT_NAME_LENGTH + 3)
+ /* no space left for name (+ type + len) */
+ if ((max_adv_len(hdev) - ad_len) < HCI_MAX_SHORT_NAME_LENGTH + 2)
return ad_len;

/* use complete name if present and fits */
complete_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));
if (complete_len && complete_len <= HCI_MAX_SHORT_NAME_LENGTH)
- return eir_append_name(ptr, ad_len, EIR_NAME_COMPLETE,
- hdev->dev_name, complete_len + 1);
+ return eir_append_data(ptr, ad_len, EIR_NAME_COMPLETE,
+ hdev->dev_name, complete_len);

/* use short name if present */
short_len = strnlen(hdev->short_name, sizeof(hdev->short_name));
if (short_len)
- return eir_append_name(ptr, ad_len, EIR_NAME_SHORT,
+ return eir_append_data(ptr, ad_len, EIR_NAME_SHORT,
hdev->short_name,
- short_len == HCI_MAX_SHORT_NAME_LENGTH ?
- short_len : short_len + 1);
+ short_len);

/* use shortened full name if present, we already know that name
* is longer then HCI_MAX_SHORT_NAME_LENGTH
*/
if (complete_len)
- return eir_append_name(ptr, ad_len, EIR_NAME_SHORT,
+ return eir_append_data(ptr, ad_len, EIR_NAME_SHORT,
hdev->dev_name,
HCI_MAX_SHORT_NAME_LENGTH);

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index cc8efdc4ad431..640d6d54ac6ba 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -8400,7 +8400,7 @@ static int read_adv_features(struct sock *sk, struct hci_dev *hdev,

static u8 calculate_name_len(struct hci_dev *hdev)
{
- u8 buf[HCI_MAX_SHORT_NAME_LENGTH + 3];
+ u8 buf[HCI_MAX_SHORT_NAME_LENGTH + 2]; /* len + type + name */

return eir_append_local_name(hdev, buf, 0);
}
--
2.43.0