From: Michael Bommarito Date: Fri, 15 May 2026 14:38:19 +0000 (-0400) Subject: Bluetooth: MGMT: validate Add Extended Advertising Data length X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d3f7d17960ed50df3a6709c5158caff989c8c905;p=thirdparty%2Fkernel%2Flinux.git Bluetooth: MGMT: validate Add Extended Advertising Data length MGMT_OP_ADD_EXT_ADV_DATA is registered as a variable-length command, with MGMT_ADD_EXT_ADV_DATA_SIZE as the fixed header size. The handler then uses cp->adv_data_len and cp->scan_rsp_len to validate and copy cp->data, but it never checks that those bytes are part of the mgmt command payload. A short command can therefore make add_ext_adv_data() pass an out-of-bounds pointer into tlv_data_is_valid(). If the bytes beyond the command buffer are addressable, they can also be copied into the advertising instance as scan response data, where the caller can read them back via MGMT_OP_GET_ADV_INSTANCE. The trigger requires CAP_NET_ADMIN in the initial user namespace; KASAN reports an 8-byte slab-out-of-bounds read. Reject commands whose length does not match the fixed header plus both advertising data lengths before parsing cp->data. Fixes: 12410572833a ("Bluetooth: Break add adv into two mgmt commands") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Signed-off-by: Luiz Augusto von Dentz --- diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c index b05bb380e5f8..de5bd6b637b2 100644 --- a/net/bluetooth/mgmt.c +++ b/net/bluetooth/mgmt.c @@ -9110,9 +9110,15 @@ static int add_ext_adv_data(struct sock *sk, struct hci_dev *hdev, void *data, struct adv_info *adv_instance; int err = 0; struct mgmt_pending_cmd *cmd; + u16 expected_len; BT_DBG("%s", hdev->name); + expected_len = struct_size(cp, data, cp->adv_data_len + cp->scan_rsp_len); + if (expected_len != data_len) + return mgmt_cmd_status(sk, hdev->id, MGMT_OP_ADD_EXT_ADV_DATA, + MGMT_STATUS_INVALID_PARAMS); + hci_dev_lock(hdev); adv_instance = hci_find_adv_instance(hdev, cp->instance);