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 D5366C00140 for ; Fri, 12 Aug 2022 13:41:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238383AbiHLNlt (ORCPT ); Fri, 12 Aug 2022 09:41:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236979AbiHLNlq (ORCPT ); Fri, 12 Aug 2022 09:41:46 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EEDE9F751 for ; Fri, 12 Aug 2022 06:41:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B07D3617E8 for ; Fri, 12 Aug 2022 13:41:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4873EC433D6; Fri, 12 Aug 2022 13:41:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660311705; bh=m1iZhLzdIcy6lPMcG+UufINcqDuACgcrNOkjp/F6Obw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QpO32sO8PhYZEVT69tBOA1fR9EtwY32slMa1L5mgbesYV20NEzpJtzfGPrbY4SYHH +/EvCbkKkV7nPz9o//Lw1tcQ7BKsmG2jgYMD54wKPx0/1NVOvKk5XsixDQHv1Wse02 tr1pJR100XM1FVmIB9/lWxEl4vKUMtCCIXCtMh26RM9c+W/SW9iGRooujCeR92zFTC R1Pvy9qedeJc931avUsm1OK28ckVKdB4PriNwAwZlaWPMucrEEdFF+nh6M+uYpFHDd UdcB8+TYxQaO5/Cm8KywwEVHr/+CJaUCy4uOx+XAL1WeqqFnZOCAJN2pJhMR7skoyr kcRpFdgAnAg2g== Date: Fri, 12 Aug 2022 15:41:38 +0200 From: Christian Brauner To: Dongliang Mu Cc: Greg Kroah-Hartman , Arve =?utf-8?B?SGrDuG5uZXbDpWc=?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Carlos Llamas , Suren Baghdasaryan , Kees Cook , Dongliang Mu , syzkaller , linux-kernel@vger.kernel.org Subject: Re: [PATCH] drivers: binderfs: fix memory leak in binderfs_fill_super Message-ID: <20220812134138.gpu7274yahlvr6hr@wittgenstein> References: <20220812132124.2053673-1-dzm91@hust.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220812132124.2053673-1-dzm91@hust.edu.cn> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 12, 2022 at 09:21:24PM +0800, Dongliang Mu wrote: > From: Dongliang Mu > > In binderfs_fill_super, if s_root is not successfully initialized by > d_make_root, the previous allocated s_sb_info will not be freed since > generic_shutdown_super first checks if sb->s_root and then does > put_super operation. The put_super operation calls binderfs_put_super > to deallocate s_sb_info and put ipc_ns. This will lead to memory leak > in binderfs_fill_super. > > Fix this by invoking binderfs_put_super at error sites before s_root > is successfully initialized. > > Fixes: 095cf502b31e ("binderfs: port to new mount api") > Reported-by: syzkaller > Signed-off-by: Dongliang Mu > --- Seems right but where's the full syzbot link to the issue? Also, wouldn't (untested) sm like the below be better?: diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c index 588d753a7a19..4582b043d21e 100644 --- a/drivers/android/binderfs.c +++ b/drivers/android/binderfs.c @@ -692,6 +692,15 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_magic = BINDERFS_SUPER_MAGIC; sb->s_op = &binderfs_super_ops; sb->s_time_gran = 1; + sb->s_fs_info = NULL; + + inode = new_inode(sb); + if (!inode) + return -ENOMEM; + + sb->s_root = d_make_root(inode); + if (!sb->s_root) + return -ENOMEM; sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); if (!sb->s_fs_info) @@ -709,10 +718,6 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) info->mount_opts.max = ctx->max; info->mount_opts.stats_mode = ctx->stats_mode; - inode = new_inode(sb); - if (!inode) - return -ENOMEM; - inode->i_ino = FIRST_INODE; inode->i_fop = &simple_dir_operations; inode->i_mode = S_IFDIR | 0755; @@ -720,10 +725,6 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) inode->i_op = &binderfs_dir_inode_operations; set_nlink(inode, 2); - sb->s_root = d_make_root(inode); - if (!sb->s_root) - return -ENOMEM; - ret = binderfs_binder_ctl_create(sb); if (ret) return ret; > drivers/android/binderfs.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c > index 588d753a7a19..20f5bc77495f 100644 > --- a/drivers/android/binderfs.c > +++ b/drivers/android/binderfs.c > @@ -710,8 +710,10 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) > info->mount_opts.stats_mode = ctx->stats_mode; > > inode = new_inode(sb); > - if (!inode) > + if (!inode) { > + binderfs_put_super(sb); > return -ENOMEM; > + } > > inode->i_ino = FIRST_INODE; > inode->i_fop = &simple_dir_operations; > @@ -721,8 +723,10 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) > set_nlink(inode, 2); > > sb->s_root = d_make_root(inode); > - if (!sb->s_root) > + if (!sb->s_root) { > + binderfs_put_super(sb); > return -ENOMEM; > + } > > ret = binderfs_binder_ctl_create(sb); > if (ret) > -- > 2.25.1 >