CVE-2026-43435: rust_binder: fix oneway spam detection

CVE-2026-43435: rust_binder: fix oneway spam detection

[Greg Kroah-Hartman]

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

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

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

rust_binder: fix oneway spam detection

The spam detection logic in TreeRange was executed before the current
request was inserted into the tree. So the new request was not being
factored in the spam calculation. Fix this by moving the logic after
the new range has been inserted.

Also, the detection logic for ArrayRange was missing altogether which
meant large spamming transactions could get away without being detected.
Fix this by implementing an equivalent low_oneway_space() in ArrayRange.

Note that I looked into centralizing this logic in RangeAllocator but
iterating through 'state' and 'size' got a bit too complicated (for me)
and I abandoned this effort.

The Linux kernel CVE team has assigned CVE-2026-43435 to this issue.


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

	Issue introduced in 6.18 with commit eafedbc7c050c44744fbdf80bdf3315e860b7513 and fixed in 6.18.19 with commit edf685946c4acbe57cb96f8d5f3c07e9a2e973c8
	Issue introduced in 6.18 with commit eafedbc7c050c44744fbdf80bdf3315e860b7513 and fixed in 6.19.9 with commit 8d34c993a9a156e657e43cb95186980745cc3597
	Issue introduced in 6.18 with commit eafedbc7c050c44744fbdf80bdf3315e860b7513 and fixed in 7.0 with commit 4fc87c240b8f30e22b7ebaae29d57105589e1c0b

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-2026-43435
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/range_alloc/array.rs
	drivers/android/binder/range_alloc/mod.rs
	drivers/android/binder/range_alloc/tree.rs


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/edf685946c4acbe57cb96f8d5f3c07e9a2e973c8
	https://git.kernel.org/stable/c/8d34c993a9a156e657e43cb95186980745cc3597
	https://git.kernel.org/stable/c/4fc87c240b8f30e22b7ebaae29d57105589e1c0b