eir_get_service_data() reads a 16-bit UUID from the service data using
get_unaligned_le16() without first checking that the data is long enough
to hold a UUID16 (2 bytes). If a malformed EIR entry has a service data
field with only 1 byte of payload (field_len=2), eir_get_data() returns
dlen=1. The subsequent get_unaligned_le16() then reads 1 byte past the
field boundary.
Additionally, if the corrupted UUID happens to match, the length
calculation "dlen - 2" underflows to SIZE_MAX since dlen is size_t.
Current callers either pass NULL for the length parameter or bounds-check
the returned length, but future callers may not.
Add a check that dlen >= sizeof(u16) and skip fields that are too short
to contain a valid UUID16.
Fixes: 8f9ae5b3ae ("Bluetooth: eir: Add helpers for managing service data")
Cc: stable@vger.kernel.org
Signed-off-by: Aamir Ahmed <elb12345@hotmail.co.uk>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
eir_get_service_data() walks the advertising data for a Service Data
field with a matching UUID. On a mismatch it advances:
eir += dlen;
eir_len -= dlen;
eir_get_data() reports dlen as the field's data length, but the field
spans dlen + 2 bytes once its length and type bytes count, and more
when non-Service-Data fields were skipped to reach it. The pointer
lands correctly on the next field. eir_len does not, and the shortfall
compounds across fields until eir_get_data() reads the length and type
bytes of a "field" past the end of the buffer.
For an ISO broadcast sink that buffer is hcon->le_per_adv_data[], filled
from the periodic advertising reports of a remote broadcaster. A PA
payload packed with mismatching Service Data fields walks off the array
into the rest of struct hci_conn. A drifted field that matches the BAA
UUID puts those bytes in iso_pi(sk)->base, where user space reads them
back with getsockopt(BT_ISO_BASE).
Recompute eir_len from the end of the buffer each iteration.
Fixes: 8f9ae5b3ae ("Bluetooth: eir: Add helpers for managing service data")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-5
Signed-off-by: HyeongJun An <sammiee5311@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
eir_create_adv_data() builds the advertising data into a fixed-size
buffer ("size", 31 for the legacy path). It may prepend a 3-byte "Flags"
AD structure (LE_AD_NO_BREDR on an LE-only controller) and then copies
the per-instance data without checking that it still fits:
memcpy(ptr, adv->adv_data, adv->adv_data_len);
tlv_data_max_len() only reserves those 3 bytes when the user-supplied
flags carry a managed-flags bit, so an instance added with flags == 0 is
accepted with adv_data_len up to the full buffer. At advertise time the
flags are still prepended, and the memcpy() writes 3 + adv_data_len
bytes into the size-byte buffer:
BUG: KASAN: stack-out-of-bounds in eir_create_adv_data (net/bluetooth/eir.c:301)
Write of size 31 at addr ffff88800a547bdc by task kworker/u9:0/65
Workqueue: hci0 hci_cmd_sync_work
__asan_memcpy (mm/kasan/shadow.c:106)
eir_create_adv_data (net/bluetooth/eir.c:301)
hci_update_adv_data_sync (net/bluetooth/hci_sync.c:1310)
hci_schedule_adv_instance_sync (net/bluetooth/hci_sync.c:1817)
hci_cmd_sync_work (net/bluetooth/hci_sync.c:332)
This frame has 1 object:
[32, 64) 'cp'
The "Flags" structure is added by the kernel, not requested by
userspace, so only prepend it when it fits together with the instance
advertising data; when there is no room for both, drop the flags rather
than the user-provided data.
Reachable by a local user with CAP_NET_ADMIN owning an LE-only
controller on the legacy advertising path.
Fixes: b44133ff03 ("Bluetooth: Support the "discoverable" adv flag")
Reported-by: Xiang Mei <xmei5@asu.edu>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
eir_create_adv_data may attempt to add EIR_FLAGS and EIR_TX_POWER
without checking if that would fit.
Link: https://github.com/bluez/bluez/issues/1117#issuecomment-2958244066
Fixes: 01ce70b0a2 ("Bluetooth: eir: Move EIR/Adv Data functions to its own file")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
The len parameter is considered optional so it can be NULL so it cannot
be used for skipping to next entry of EIR_SERVICE_DATA.
Fixes: 8f9ae5b3ae ("Bluetooth: eir: Add helpers for managing service data")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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: f61851f64b ("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>
There a few instances still using HCI_MAX_AD_LENGTH instead of using
max_adv_len which takes care of detecting what is the actual maximum
length depending on if the controller supports EA or not.
Fixes: 112b5090c2 ("Bluetooth: MGMT: Fix always using HCI_MAX_AD_LENGTH")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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>
This adds helpers for accessing and appending service data (0x16) ad
type.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This moves functions manipulating EIR/Adv Data to its own file so it
can be reused by other files.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
