From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E262FC43381 for ; Mon, 28 Dec 2020 18:56:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A468F221F8 for ; Mon, 28 Dec 2020 18:56:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728876AbgL1S4K (ORCPT ); Mon, 28 Dec 2020 13:56:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:39488 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728869AbgL1S4J (ORCPT ); Mon, 28 Dec 2020 13:56:09 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D183A22AAD; Mon, 28 Dec 2020 18:55:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1609181729; bh=Qv8XPvD4Whz8DkvwGwAf7mmtYtvGPNNWzNeowimMGrM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k0LLBzMoZ0aHGfOBsg3ITTIW0dgo1gTH+nM+OngQXse5z6gWy3lvNwUyvKs6g+p9M WRElB9XR6KPx8r9J9nxTkurn05YA7qHcQ8c89ve1zpJp3m1+uT89+1x2bueSLqkNHh 3HR9gG6QzcO36mQf1mr1IToFU2ia1oxP6TB107pAeDSlI+9XNgChm5GGD0xvh/uIYP 5Cv8F1LqjQZ3fb4/NkaXYU9ekLU9g7lHPVkOVRgpEDP+A6Y0ATp2yUuULup5HwyMG5 4/fQRDmYSPSMECifsZACf/4Fp0VnZXeIUJsGi86UuidY7mBk5IlZQhBtlsqlzYp5w0 GF1YPOknLE9nA== From: Eric Biggers To: stable@vger.kernel.org Cc: linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org Subject: [PATCH 5.4 2/4] ext4: prevent creating duplicate encrypted filenames Date: Mon, 28 Dec 2020 10:54:31 -0800 Message-Id: <20201228185433.61129-3-ebiggers@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228185433.61129-1-ebiggers@kernel.org> References: <20201228185433.61129-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Eric Biggers commit 75d18cd1868c2aee43553723872c35d7908f240f upstream. As described in "fscrypt: add fscrypt_is_nokey_name()", it's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the directory's encryption key. Fix this bug on ext4 by rejecting no-key dentries in ext4_add_entry(). Note that the duplicate check in ext4_find_dest_de() sometimes prevented this bug. However in many cases it didn't, since ext4_find_dest_de() doesn't examine every dentry. Fixes: 4461471107b7 ("ext4 crypto: enable filename encryption") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-3-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/ext4/namei.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 36a81b57012a5..59038e361337c 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2192,6 +2192,9 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry, if (!dentry->d_name.len) return -EINVAL; + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; + #ifdef CONFIG_UNICODE if (ext4_has_strict_mode(sbi) && IS_CASEFOLDED(dir) && sbi->s_encoding && utf8_validate(sbi->s_encoding, &dentry->d_name)) -- 2.29.2