Subject: CVE-2024-26606: binder: signal epoll threads of self-work

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

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

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

binder: signal epoll threads of self-work

In (e)poll mode, threads often depend on I/O events to determine when
data is ready for consumption. Within binder, a thread may initiate a
command via BINDER_WRITE_READ without a read buffer and then make use
of epoll_wait() or similar to consume any responses afterwards.

It is then crucial that epoll threads are signaled via wakeup when they
queue their own work. Otherwise, they risk waiting indefinitely for an
event leaving their work unhandled. What is worse, subsequent commands
won't trigger a wakeup either as the thread has pending work.

The Linux kernel CVE team has assigned CVE-2024-26606 to this issue.

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

	Issue introduced in 2.6.29 with commit 457b9a6f09f0 and fixed in 4.19.307 with commit dd64bb8329ce
	Issue introduced in 2.6.29 with commit 457b9a6f09f0 and fixed in 5.4.269 with commit 42beab162dce
	Issue introduced in 2.6.29 with commit 457b9a6f09f0 and fixed in 5.10.210 with commit a423042052ec
	Issue introduced in 2.6.29 with commit 457b9a6f09f0 and fixed in 5.15.149 with commit 82722b453dc2
	Issue introduced in 2.6.29 with commit 457b9a6f09f0 and fixed in 6.1.79 with commit 90e09c016d72
	Issue introduced in 2.6.29 with commit 457b9a6f09f0 and fixed in 6.6.18 with commit a7ae586f6f60
	Issue introduced in 2.6.29 with commit 457b9a6f09f0 and fixed in 6.7.6 with commit 93b372c39c40
	Issue introduced in 2.6.29 with commit 457b9a6f09f0 and fixed in 6.8 with commit 97830f3c3088

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-2024-26606
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/dd64bb8329ce0ea27bc557e4160c2688835402ac
	https://git.kernel.org/stable/c/42beab162dcee1e691ee4934292d51581c29df61
	https://git.kernel.org/stable/c/a423042052ec2bdbf1e552e621e6a768922363cc
	https://git.kernel.org/stable/c/82722b453dc2f967b172603e389ee7dc1b3137cc
	https://git.kernel.org/stable/c/90e09c016d72b91e76de25f71c7b93d94cc3c769
	https://git.kernel.org/stable/c/a7ae586f6f6024f490b8546c8c84670f96bb9b68
	https://git.kernel.org/stable/c/93b372c39c40cbf179e56621e6bc48240943af69
	https://git.kernel.org/stable/c/97830f3c3088638ff90b20dfba2eb4d487bf14d7