From patchwork Mon Jul 12 06:12:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 475609 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,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 15482C11F97 for ; Mon, 12 Jul 2021 07:29:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 049236115A for ; Mon, 12 Jul 2021 07:29:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347049AbhGLHcB (ORCPT ); Mon, 12 Jul 2021 03:32:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:43510 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345274AbhGLH3n (ORCPT ); Mon, 12 Jul 2021 03:29:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C3D7F61613; Mon, 12 Jul 2021 07:26:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626074764; bh=RtWuVmcFlAjsPSFFHOaPn9GmQSPNvNq00+3sAYldAJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VXZS1Bjg06NA28hBLTcF5ZR99+B0dhU8Ge6tnrdPU2qyjpkupfNTWeCK0cM+qoslA ewAOpiuHwUosUIFu3EXJT0X6cJpEDzFR/yKHfGlSAAYdQ0FQDbc5nnMLr3YFYP/jEC 1CGZoQbJQOC9pFsTXOGPl8iSZNRbU+OGr6uUodOo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Biggers Subject: [PATCH 5.12 689/700] fscrypt: dont ignore minor_hash when hash is 0 Date: Mon, 12 Jul 2021 08:12:52 +0200 Message-Id: <20210712061049.257161805@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060924.797321836@linuxfoundation.org> References: <20210712060924.797321836@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Biggers commit 77f30bfcfcf484da7208affd6a9e63406420bf91 upstream. 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+ Link: https://lore.kernel.org/r/20210527235236.2376556-1-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- fs/crypto/fname.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -344,13 +344,9 @@ int fscrypt_fname_disk_to_usr(const stru 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]);