Subject: CVE-2024-26926: binder: check offset alignment in binder_get_object()

From: Greg Kroah-Hartman <[email-masked]>

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

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

binder: check offset alignment in binder_get_object()

Commit 6d98eb95b450 ("binder: avoid potential data leakage when copying
txn") introduced changes to how binder objects are copied. In doing so,
it unintentionally removed an offset alignment check done through calls
to binder_alloc_copy_from_buffer() -> check_buffer().

These calls were replaced in binder_get_object() with copy_from_user(),
so now an explicit offset alignment check is needed here. This avoids
later complications when unwinding the objects gets harder.

It is worth noting this check existed prior to commit 7a67a39320df
("binder: add function to copy binder object from buffer"), likely
removed due to redundancy at the time.

The Linux kernel CVE team has assigned CVE-2024-26926 to this issue.

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

	Issue introduced in 5.4.226 with commit c056a6ba35e0 and fixed in 5.4.275 with commit 68a28f551e46
	Issue introduced in 5.10.157 with commit 23e9d815fad8 and fixed in 5.10.216 with commit 48a1f83ca9c6
	Issue introduced in 5.15.17 with commit 7a9ad4aceb02 and fixed in 5.15.157 with commit a2fd6dbc98be
	Issue introduced in 5.17 with commit 6d98eb95b450 and fixed in 6.1.88 with commit a6d2a8b211c8
	Issue introduced in 5.17 with commit 6d98eb95b450 and fixed in 6.6.29 with commit 1d7f1049035b
	Issue introduced in 5.17 with commit 6d98eb95b450 and fixed in 6.8.8 with commit f01d66190457
	Issue introduced in 5.17 with commit 6d98eb95b450 and fixed in 6.9 with commit aaef73821a3b
	Issue introduced in 5.16.3 with commit 66e12f5b3a97

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-2024-26926
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:
	drivers/android/binder.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/68a28f551e4690db2b27b3db716c7395f6fada12
	https://git.kernel.org/stable/c/48a1f83ca9c68518b1a783c62e6a8223144fa9fc
	https://git.kernel.org/stable/c/a2fd6dbc98be1105a1d8e9e31575da8873ef115c
	https://git.kernel.org/stable/c/a6d2a8b211c874971ee4cf3ddd167408177f6e76
	https://git.kernel.org/stable/c/1d7f1049035b2060342f11eff957cf567d810bdc
	https://git.kernel.org/stable/c/f01d6619045704d78613b14e2e0420bfdb7f1c15
	https://git.kernel.org/stable/c/aaef73821a3b0194a01bd23ca77774f704a04d40