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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86607C001DF for ; Thu, 3 Aug 2023 08:58:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234909AbjHCI6b (ORCPT ); Thu, 3 Aug 2023 04:58:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234857AbjHCI6T (ORCPT ); Thu, 3 Aug 2023 04:58:19 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6526EE58; Thu, 3 Aug 2023 01:58:18 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 2371B219AE; 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Thu, 3 Aug 2023 08:58:16 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id DF/gKChsy2TFYwAAMHmgww (envelope-from ); Thu, 03 Aug 2023 08:58:16 +0000 Received: from localhost (brahms.olymp [local]) by brahms.olymp (OpenSMTPD) with ESMTPA id 66f404ce; Thu, 3 Aug 2023 08:58:15 +0000 (UTC) From: =?utf-8?Q?Lu=C3=ADs_Henriques?= To: Eric Biggers Cc: Theodore Ts'o , Andreas Dilger , Daniel Rosenberg , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] ext4: fix memory leaks in ext4_fname_{setup_filename,prepare_lookup} In-Reply-To: <20230803041918.GA1218@sol.localdomain> (Eric Biggers's message of "Wed, 2 Aug 2023 21:19:18 -0700") References: <20230802094931.18215-1-lhenriques@suse.de> <20230803041918.GA1218@sol.localdomain> Date: Thu, 03 Aug 2023 09:58:15 +0100 Message-ID: <87sf90v6xk.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Eric Biggers writes: > On Wed, Aug 02, 2023 at 10:49:31AM +0100, Lu=C3=ADs Henriques wrote: >> If casefolding the filename fails, we'll be leaking fscrypt_buf name. > > fscrypt_buf =3D> fscrypt_name > >> diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c >> index e20ac0654b3f..3c05c7f3415b 100644 >> --- a/fs/ext4/crypto.c >> +++ b/fs/ext4/crypto.c >> @@ -33,6 +33,8 @@ int ext4_fname_setup_filename(struct inode *dir, const= struct qstr *iname, >> struct fscrypt_name name; >> int err; >> >> err =3D fscrypt_setup_filename(dir, iname, lookup, &name); >> if (err) >> return err; >> >> ext4_fname_from_fscrypt_name(fname, &name); >> >> #if IS_ENABLED(CONFIG_UNICODE) >> err =3D ext4_fname_setup_ci_filename(dir, iname, fname); >> + if (err) >> + fscrypt_free_filename(&name); >> #endif >> return err; >> } >> @@ -51,6 +53,8 @@ int ext4_fname_prepare_lookup(struct inode *dir, struc= t dentry *dentry, >> struct fscrypt_name name; >> int err; >> >> err =3D fscrypt_prepare_lookup(dir, dentry, &name); >> if (err) >> return err; >> >> ext4_fname_from_fscrypt_name(fname, &name); >> >> #if IS_ENABLED(CONFIG_UNICODE) >> err =3D ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname); >> + if (err) >> + fscrypt_free_filename(&name); >> #endif >> return err; >> } > > This works, but it's a bit weird that the freeing happens on the original= struct > fscrypt_name after it has already been "moved" to the struct ext4_filenam= e by > ext4_fname_from_fscrypt_name(). That leaves a dangling pointer in the st= ruct > ext4_filename. Maybe you should call ext4_fname_free_filename() instead,= even > though it would do some unnecessary work? That makes sense, specially because fname is a parameter and it's probably a good idea to clean-up everything before returning an error. Thanks. Cheers, --=20 Lu=C3=ADs