Subject: CVE-2024-26936: ksmbd: validate request buffer size in smb2_allocate_rsp_buf()

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

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

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

ksmbd: validate request buffer size in smb2_allocate_rsp_buf()

The response buffer should be allocated in smb2_allocate_rsp_buf
before validating request. But the fields in payload as well as smb2 header
is used in smb2_allocate_rsp_buf(). This patch add simple buffer size
validation to avoid potencial out-of-bounds in request buffer.

The Linux kernel CVE team has assigned CVE-2024-26936 to this issue.

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

	Fixed in 5.15.159 with commit 8f3d0bf1d0c6
	Fixed in 6.1.88 with commit 21ff9d7d223c
	Fixed in 6.6.29 with commit 5c20b242d4fe
	Fixed in 6.8.8 with commit 2c27a64a2bc4
	Fixed in 6.9 with commit 17cf0c2794bd

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-2024-26936
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:
	fs/smb/server/smb2pdu.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/8f3d0bf1d0c62b539d54c5b9108a845cff619b99
	https://git.kernel.org/stable/c/21ff9d7d223c5c19cb4334009e4c0c83a2f4d674
	https://git.kernel.org/stable/c/5c20b242d4fed73a93591e48bfd9772e2322fb11
	https://git.kernel.org/stable/c/2c27a64a2bc47d9bfc7c3cf8be14be53b1ee7cb6
	https://git.kernel.org/stable/c/17cf0c2794bdb6f39671265aa18aea5c22ee8c4a