CVE-2026-89498: orangefs: fix double-free of trailer_buf on readdir copy failure

CVE-2026-89498: orangefs: fix double-free of trailer_buf on readdir copy failure

[Greg Kroah-Hartman]

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

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

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

orangefs: fix double-free of trailer_buf on readdir copy failure

On a readdir downcall, orangefs_devreq_write_iter() frees
op->downcall.trailer_buf with vfree() when copy_from_iter_full() fails,
but does not clear the pointer before goto Efault. The waiter in
do_readdir() is then woken with a negative status and frees the same
pointer again on its r < 0 path, causing a deterministic double-free.
A client holding /dev/pvfs2-req triggers it by sending a readdir
downcall whose declared trailer_size exceeds the bytes it supplies.

Clear the pointer after freeing so the readdir-side vfree() becomes a
no-op.

The Linux kernel CVE team has assigned CVE-2026-89498 to this issue.


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

	Issue introduced in 4.12 with commit 382f4581e67f57209c7aa67e39f26ba076306a2e and fixed in 6.12.109 with commit 2f5454a25127854c232fde5d1d65d16fbcd42d43
	Issue introduced in 4.12 with commit 382f4581e67f57209c7aa67e39f26ba076306a2e and fixed in 6.18.50 with commit f796f38a324e89547738f4b70cc33be5be2bc6da
	Issue introduced in 4.12 with commit 382f4581e67f57209c7aa67e39f26ba076306a2e and fixed in 7.2.4 with commit 519f4146b8b8c5f20c2ad01913acd6df2df8fc8e
	Issue introduced in 4.12 with commit 382f4581e67f57209c7aa67e39f26ba076306a2e and fixed in 7.3-rc1 with commit f574296be7f46eb60beca851240b526df232f480

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-2026-89498
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/orangefs/devorangefs-req.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/2f5454a25127854c232fde5d1d65d16fbcd42d43
	https://git.kernel.org/stable/c/f796f38a324e89547738f4b70cc33be5be2bc6da
	https://git.kernel.org/stable/c/519f4146b8b8c5f20c2ad01913acd6df2df8fc8e
	https://git.kernel.org/stable/c/f574296be7f46eb60beca851240b526df232f480