linux-kernel - WTF is d_add_ci() doing with negative dentries?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20141012221817.GU7996@ZenIV.linux.org.uk>
Date:	Sun, 12 Oct 2014 23:18:17 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: WTF is d_add_ci() doing with negative dentries?

	AFAICS, if d_add_ci() ever finds a negative hashed dentry for
exact name, it's already buggered.  Because right *before* that
d_add_ci() lookup for exact name would've turned valid negative.
IOW, the whole thing ought to be
        found = d_hash_and_lookup(dentry->d_parent, name);
	if (found) {
		iput(inode);
		return found;
	}
	new = d_alloc(dentry->d_parent, name);
	if (!new) {
		iput(inode);
		return ERR_PTR(-ENOMEM);
	}
	found = d_splice_alias(inode, new);
	if (found) {
		dput(new);
		return found;
	}
	return new;
Moreover, it might very well be better to pass dentry->d_parent instead
of dentry...  Objections?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/