From: Al Viro <viro@zeniv.linux.org.uk>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
Christian Brauner <brauner@kernel.org>,
Stefan Berger <stefanb@linux.ibm.com>,
Mimi Zohar <zohar@linux.ibm.com>,
linux-unionfs@vger.kernel.org, linux-integrity@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 2/2] fs: remove the inode argument to ->d_real() method
Date: Fri, 2 Feb 2024 16:16:01 +0000 [thread overview]
Message-ID: <20240202161601.GA976131@ZenIV> (raw)
In-Reply-To: <20240202160509.GZ2087318@ZenIV>
On Fri, Feb 02, 2024 at 04:05:09PM +0000, Al Viro wrote:
> Use After Free. Really. And "untrusted" in the function name does not
> refer to "it might be pointing to unmapped page" - it's just "don't
> expect anything from the characters you might find there, including
> the presence of NUL".
Argh... s/including/beyond the/ - sorry. Messed up rewriting the
sentence.
"Untrusted" refers to the lack of whitespaces, control characters, '"',
etc. What audit_log_untrustedstring(ab, string) expects is
* string pointing to readable memory object
* the object remaining unchanged through the call
* NUL existing somewhere in that object.
All of those assertions can be violated once the object string
used to point to has been passed to kmem_cache_free(). Which is what
can very well happen to filename pointer in this case.
next prev parent reply other threads:[~2024-02-02 16:16 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-02 11:01 [PATCH 0/2] Decomplicate file_dentry() Amir Goldstein
2024-02-02 11:01 ` [PATCH 1/2] fs: make file_dentry() a simple accessor Amir Goldstein
2024-02-02 15:16 ` Stefan Berger
2024-02-02 11:01 ` [PATCH 2/2] fs: remove the inode argument to ->d_real() method Amir Goldstein
2024-02-02 12:19 ` Miklos Szeredi
2024-02-02 12:41 ` Amir Goldstein
2024-02-02 13:54 ` Christian Brauner
2024-02-06 15:28 ` Amir Goldstein
2024-02-02 15:17 ` Stefan Berger
2024-02-02 16:05 ` Al Viro
2024-02-02 16:16 ` Al Viro [this message]
2024-02-02 17:34 ` Stefan Berger
2024-02-02 18:27 ` Al Viro
2024-02-02 18:32 ` Stefan Berger
2024-02-02 18:50 ` Al Viro
2024-02-02 18:38 ` Al Viro
2024-02-06 16:02 ` [PATCH 0/2] Decomplicate file_dentry() Christian Brauner
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