From: Will Rosenberg <whrosenb@asu.edu>
To: Tejun Heo <tj@kernel.org>
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Oliver Rosenberg" <olrose55@gmail.com>,
杜义恒 <duyiheng@tju.edu.cn>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] kernfs: fix NULL pointer dereference in __kernfs_new_node()
Date: Sun, 1 Feb 2026 10:41:47 -0700 [thread overview]
Message-ID: <aX+QW0yMZwVL5Y4h@gmail.com> (raw)
In-Reply-To: <f5fe5674adee792e663a86d680d836c5@kernel.org>
On Sun, Feb 01, 2026 at 07:05:50AM -1000, Tejun Heo wrote:
> Commit 382b1e8f30f7 ("kernfs: fix memory leak of kernfs_iattrs in
> __kernfs_new_node") introduced an err_out4 error path which frees iattr
> when security_kernfs_init_security() fails. However, iattr is only
> allocated by __kernfs_setattr() when the node has non-default uid/gid.
> If the node uses default ownership, iattr remains NULL, and
> security_kernfs_init_security() failure would cause a NULL pointer
> dereference when err_out4 tries to access kn->iattr->xattrs.
>
> Add a NULL check before freeing iattr.
>
> Fixes: 382b1e8f30f7 ("kernfs: fix memory leak of kernfs_iattrs in __kernfs_new_node")
Thank you for reporting the bug.
This bug has been fixed by Commit 2b742094582d ("fs/kernfs: null-ptr deref in simple_xattrs_free()").
Commit 382b1e8f30f7 ("kernfs: fix memory leak of kernfs_iattrs in __kernfs_new_node")
was also caught from entering any stable releases, so the bug should be
fixed on all active branches.
Please correct me if this bug has not been fully addressed.
--
Will Rosenberg
prev parent reply other threads:[~2026-02-01 17:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <AOoAIQD0J-9V1NW0JM55A4po.1.1769761572059.Hmail.3019244382@tju.edu.cn>
2026-02-01 17:05 ` [PATCH] kernfs: fix NULL pointer dereference in __kernfs_new_node() Tejun Heo
2026-02-01 17:41 ` Will Rosenberg [this message]
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