CVE-2026-89583: Bluetooth: eir: Fix OOB read in eir_get_service_data()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: eir: Fix OOB read in eir_get_service_data()

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.

The Linux kernel CVE team has assigned CVE-2026-89583 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.19 with commit 8f9ae5b3ae80f168a6224529e3787f4fb27f299a and fixed in 6.12.109 with commit 815fc98c227a78cbd93d4c29f2833705b7c2bc0f
	Issue introduced in 5.19 with commit 8f9ae5b3ae80f168a6224529e3787f4fb27f299a and fixed in 6.18.50 with commit c21fa79301d7d6ac0a4ec6c51e8ba10beaa08c50
	Issue introduced in 5.19 with commit 8f9ae5b3ae80f168a6224529e3787f4fb27f299a and fixed in 7.2.4 with commit bb56e97bd67614238c1c0a4084704ccadbb875b4
	Issue introduced in 5.19 with commit 8f9ae5b3ae80f168a6224529e3787f4fb27f299a and fixed in 7.3-rc1 with commit 4beb198bc59b242404a47c21990bc84165052c8a

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-89583
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/bluetooth/eir.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/815fc98c227a78cbd93d4c29f2833705b7c2bc0f
	https://git.kernel.org/stable/c/c21fa79301d7d6ac0a4ec6c51e8ba10beaa08c50
	https://git.kernel.org/stable/c/bb56e97bd67614238c1c0a4084704ccadbb875b4
	https://git.kernel.org/stable/c/4beb198bc59b242404a47c21990bc84165052c8a