Subject: CVE-2024-46740: binder: fix UAF caused by offsets overwrite

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

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

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

binder: fix UAF caused by offsets overwrite

Binder objects are processed and copied individually into the target
buffer during transactions. Any raw data in-between these objects is
copied as well. However, this raw data copy lacks an out-of-bounds
check. If the raw data exceeds the data section size then the copy
overwrites the offsets section. This eventually triggers an error that
attempts to unwind the processed objects. However, at this point the
offsets used to index these objects are now corrupted.

Unwinding with corrupted offsets can result in decrements of arbitrary
nodes and lead to their premature release. Other users of such nodes are
left with a dangling pointer triggering a use-after-free. This issue is
made evident by the following KASAN report (trimmed):

  ==================================================================
  BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xe4/0x19c
  Write of size 4 at addr ffff47fc91598f04 by task binder-util/743

  CPU: 9 UID: 0 PID: 743 Comm: binder-util Not tainted 6.11.0-rc4 #1
  Hardware name: linux,dummy-virt (DT)
  Call trace:
   _raw_spin_lock+0xe4/0x19c
   binder_free_buf+0x128/0x434
   binder_thread_write+0x8a4/0x3260
   binder_ioctl+0x18f0/0x258c
  [...]

  Allocated by task 743:
   __kmalloc_cache_noprof+0x110/0x270
   binder_new_node+0x50/0x700
   binder_transaction+0x413c/0x6da8
   binder_thread_write+0x978/0x3260
   binder_ioctl+0x18f0/0x258c
  [...]

  Freed by task 745:
   kfree+0xbc/0x208
   binder_thread_read+0x1c5c/0x37d4
   binder_ioctl+0x16d8/0x258c
  [...]
  ==================================================================

To avoid this issue, let's check that the raw data copy is within the
boundaries of the data section.

The Linux kernel CVE team has assigned CVE-2024-46740 to this issue.

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

	Issue introduced in 5.4.226 with commit c056a6ba35e0 and fixed in 5.4.284 with commit 5a32bfd23022
	Issue introduced in 5.10.157 with commit 23e9d815fad8 and fixed in 5.10.226 with commit 3a8154bb4ab4
	Issue introduced in 5.15.17 with commit 7a9ad4aceb02 and fixed in 5.15.167 with commit eef79854a04f
	Issue introduced in 5.17 with commit 6d98eb95b450 and fixed in 6.1.110 with commit 4f79e0b80dc6
	Issue introduced in 5.17 with commit 6d98eb95b450 and fixed in 6.6.51 with commit 1f33d9f1d9ac
	Issue introduced in 5.17 with commit 6d98eb95b450 and fixed in 6.10.10 with commit 109e845c1184
	Issue introduced in 5.17 with commit 6d98eb95b450 and fixed in 6.11 with commit 4df153652cc4
	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-2024-46740
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/5a32bfd23022ffa7e152f273fa3fa29befb7d929
	https://git.kernel.org/stable/c/3a8154bb4ab4a01390a3abf1e6afac296e037da4
	https://git.kernel.org/stable/c/eef79854a04feac5b861f94d7b19cbbe79874117
	https://git.kernel.org/stable/c/4f79e0b80dc69bd5eaaed70f0df1b558728b4e59
	https://git.kernel.org/stable/c/1f33d9f1d9ac3f0129f8508925000900c2fe5bb0
	https://git.kernel.org/stable/c/109e845c1184c9f786d41516348ba3efd9112792
	https://git.kernel.org/stable/c/4df153652cc46545722879415937582028c18af5