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=-19.4 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=ham 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 C2625C4707F for ; Thu, 27 May 2021 23:53:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2209613D1 for ; Thu, 27 May 2021 23:53:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235827AbhE0Xyv (ORCPT ); Thu, 27 May 2021 19:54:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:43950 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233938AbhE0Xyv (ORCPT ); Thu, 27 May 2021 19:54:51 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6C18A61178; Thu, 27 May 2021 23:53:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622159597; bh=unu2CwRiIklLEI2TXoBveyWjP3PNdHwKr8/qOcOwHz0=; h=From:To:Cc:Subject:Date:From; b=hkto4pcLDdjg2amAWXxT+C//4V+e6tlGib27nP72HTOxXnR12jea3mWhtLFQ4dm0E 7gwn3yhQgn+Q9mY4pgnnWtM19dxKvdC+D3JFlgXKY/zQbcHieUH1I/os3kiQaWnWa8 7StchJcisGJpEhNQxJQIlaL4KJC1m3VRSS7Ju1ZaDoe77Col5CYNf88ewi/OFQ5RKw 7Yt6KfSlRbCNsUcDqAKmbR4xtASP6DXqsDDkYHSQCDHe3Giqjl6WSFc6N/76VUO+uy lYdSz5Vj1wzt8WHYuF05AytMP14o1V84uCWmMHAo1pYLmHfHcHGtrLFxeYcYzlanQI EH1Gc8b/jdHLw== From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, stable@vger.kernel.org Subject: [PATCH] fscrypt: don't ignore minor_hash when hash is 0 Date: Thu, 27 May 2021 16:52:36 -0700 Message-Id: <20210527235236.2376556-1-ebiggers@kernel.org> X-Mailer: git-send-email 2.32.0.rc0.204.g9fa02ecfa5-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers When initializing a no-key name, fscrypt_fname_disk_to_usr() sets the minor_hash to 0 if the (major) hash is 0. This doesn't make sense because 0 is a valid hash code, so we shouldn't ignore the filesystem-provided minor_hash in that case. Fix this by removing the special case for 'hash == 0'. This is an old bug that appears to have originated when the encryption code in ext4 and f2fs was moved into fs/crypto/. The original ext4 and f2fs code passed the hash by pointer instead of by value. So 'if (hash)' actually made sense then, as it was checking whether a pointer was NULL. But now the hashes are passed by value, and filesystems just pass 0 for any hashes they don't have. There is no need to handle this any differently from the hashes actually being 0. It is difficult to reproduce this bug, as it only made a difference in the case where a filename's 32-bit major hash happened to be 0. However, it probably had the largest chance of causing problems on ubifs, since ubifs uses minor_hash to do lookups of no-key names, in addition to using it as a readdir cookie. ext4 only uses minor_hash as a readdir cookie, and f2fs doesn't use minor_hash at all. Fixes: 0b81d0779072 ("fs crypto: move per-file encryption from f2fs tree to fs/crypto") Cc: # v4.6+ Signed-off-by: Eric Biggers --- fs/crypto/fname.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 6ca7d16593ff..d00455440d08 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -344,13 +344,9 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, offsetof(struct fscrypt_nokey_name, sha256)); BUILD_BUG_ON(BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX) > NAME_MAX); - if (hash) { - nokey_name.dirhash[0] = hash; - nokey_name.dirhash[1] = minor_hash; - } else { - nokey_name.dirhash[0] = 0; - nokey_name.dirhash[1] = 0; - } + nokey_name.dirhash[0] = hash; + nokey_name.dirhash[1] = minor_hash; + if (iname->len <= sizeof(nokey_name.bytes)) { memcpy(nokey_name.bytes, iname->name, iname->len); size = offsetof(struct fscrypt_nokey_name, bytes[iname->len]); base-commit: c4681547bcce777daf576925a966ffa824edd09d -- 2.32.0.rc0.204.g9fa02ecfa5-goog