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 CE71CC433FE for ; Wed, 26 Oct 2022 09:41:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233381AbiJZJlv (ORCPT ); Wed, 26 Oct 2022 05:41:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233158AbiJZJlu (ORCPT ); Wed, 26 Oct 2022 05:41:50 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 328BF5071F; Wed, 26 Oct 2022 02:41:49 -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-out2.suse.de (Postfix) with ESMTPS id E61EC1F74A; Wed, 26 Oct 2022 09:41:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1666777307; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HvGGmhT+mb54m/Ckk59OpGjeeAhbrk4I5c2+MnDwZWg=; b=XmA0pkXIS8rsBBbbiB2tx6W2pECUxZE4PFxaPFUCdHuTjR3rYaqmfQXc7OYc4e4nXSY5lK v9nrZ/YukMF/AULVImpWPfE3L3Z+k0jD7w+0R08DjS4dwf0/eOxRVvyxFBOdScN2CnUoN5 da8Lw7UXv2gwE6gLH8qLpb5LF4fj3UQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1666777307; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HvGGmhT+mb54m/Ckk59OpGjeeAhbrk4I5c2+MnDwZWg=; b=VnGgJPbC8H2jSSi0oAZZ2Map/uj44FZMY8jbIQfJMI7supcLEFxu7XoGVhhE/11oNVv7AW bsSTjprbi6GI38Cg== 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 imap2.suse-dmz.suse.de (Postfix) with ESMTPS id D3F0E13A6E; Wed, 26 Oct 2022 09:41:47 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 7Wj0M9sAWWMhaAAAMHmgww (envelope-from ); Wed, 26 Oct 2022 09:41:47 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 574A8A06F9; Wed, 26 Oct 2022 11:41:47 +0200 (CEST) Date: Wed, 26 Oct 2022 11:41:47 +0200 From: Jan Kara To: Baokun Li Cc: linux-ext4@vger.kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, ritesh.list@gmail.com, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yukuai3@huawei.com Subject: Re: [PATCH v3 3/4] ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode Message-ID: <20221026094147.n3hv6bk6meafc73y@quack3> References: <20221026042310.3839669-1-libaokun1@huawei.com> <20221026042310.3839669-4-libaokun1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221026042310.3839669-4-libaokun1@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Wed 26-10-22 12:23:09, Baokun Li wrote: > There are many places that will get unhappy (and crash) when ext4_iget() > returns a bad inode. However, if iget the boot loader inode, allows a bad > inode to be returned, because the inode may not be initialized. This > mechanism can be used to bypass some checks and cause panic. To solve this > problem, we add a special iget flag EXT4_IGET_BAD. Only with this flag > we'd be returning bad inode from ext4_iget(), otherwise we always return > the error code if the inode is bad inode.(suggested by Jan Kara) > > Signed-off-by: Baokun Li Looks good to me. Feel free to add: Reviewed-by: Jan Kara Honza > --- > fs/ext4/ext4.h | 3 ++- > fs/ext4/inode.c | 8 +++++++- > fs/ext4/ioctl.c | 3 ++- > 3 files changed, 11 insertions(+), 3 deletions(-) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 8d5453852f98..2b574b143bde 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -2964,7 +2964,8 @@ int do_journal_get_write_access(handle_t *handle, struct inode *inode, > typedef enum { > EXT4_IGET_NORMAL = 0, > EXT4_IGET_SPECIAL = 0x0001, /* OK to iget a system inode */ > - EXT4_IGET_HANDLE = 0x0002 /* Inode # is from a handle */ > + EXT4_IGET_HANDLE = 0x0002, /* Inode # is from a handle */ > + EXT4_IGET_BAD = 0x0004 /* Allow to iget a bad inode */ > } ext4_iget_flags; > > extern struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index ae3a836dd9d7..f767340229fd 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -5043,8 +5043,14 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, > if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb)) > ext4_error_inode(inode, function, line, 0, > "casefold flag without casefold feature"); > - brelse(iloc.bh); > + if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD)) { > + ext4_error_inode(inode, function, line, 0, > + "bad inode without EXT4_IGET_BAD flag"); > + ret = -EUCLEAN; > + goto bad_inode; > + } > > + brelse(iloc.bh); > unlock_new_inode(inode); > return inode; > > diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c > index ded535535b27..e0be8026c996 100644 > --- a/fs/ext4/ioctl.c > +++ b/fs/ext4/ioctl.c > @@ -375,7 +375,8 @@ static long swap_inode_boot_loader(struct super_block *sb, > blkcnt_t blocks; > unsigned short bytes; > > - inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO, EXT4_IGET_SPECIAL); > + inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO, > + EXT4_IGET_SPECIAL | EXT4_IGET_BAD); > if (IS_ERR(inode_bl)) > return PTR_ERR(inode_bl); > ei_bl = EXT4_I(inode_bl); > -- > 2.31.1 > -- Jan Kara SUSE Labs, CR