CVE-2026-64393: ksmbd: run set info with opener credentials

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

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

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

ksmbd: run set info with opener credentials

SMB2 SET_INFO handlers call path-based VFS helpers after checking the
access mask granted to the SMB handle. Those helpers perform their owner,
inode permission and LSM checks using the current ksmbd worker credentials.

Run the complete SET_INFO dispatch with the credentials captured when the
handle was opened. This also removes the separate security information
credential setup and keeps all SET_INFO classes under one credential scope.

Direct override_creds() is used because it can nest with the request
credential overrides already used by rename and link helpers.

The Linux kernel CVE team has assigned CVE-2026-64393 to this issue.


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

	Fixed in 6.1.178 with commit 5cbabf3a71575cd31bc7785d92d4ab42338a654b
	Fixed in 6.6.145 with commit b35afd5cf8fab236ef21117e42ee45691d4ffa7b
	Fixed in 6.12.96 with commit 0ce682867fd506f61f40c76bde7e4205bde34e87
	Fixed in 6.18.39 with commit 20ee516a62989a8d505ee432f9e59525ea23984e
	Fixed in 7.1.4 with commit 8cc9ec711f5255167247a9ab6a7179b787426ed7
	Fixed in 7.2-rc1 with commit b383bcad3d2fe634b26efbce53e22bbb5753a520

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-2026-64393
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/5cbabf3a71575cd31bc7785d92d4ab42338a654b
	https://git.kernel.org/stable/c/b35afd5cf8fab236ef21117e42ee45691d4ffa7b
	https://git.kernel.org/stable/c/0ce682867fd506f61f40c76bde7e4205bde34e87
	https://git.kernel.org/stable/c/20ee516a62989a8d505ee432f9e59525ea23984e
	https://git.kernel.org/stable/c/8cc9ec711f5255167247a9ab6a7179b787426ed7
	https://git.kernel.org/stable/c/b383bcad3d2fe634b26efbce53e22bbb5753a520