From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 357FD1E9905 for ; Tue, 10 Jun 2025 16:08:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749571712; cv=none; b=toA++AIPgApxJUItLloXThXM2eLJj8z2zaHoGpqw363Q0vmeVVEVE7Kyrc/YbaQxvjpS7zulicMnImaXhXLcmsaC/dMtng8ucI0eFWkQSaPkdnXOayx18ZFTgRProKmIJtIfcr7OSjp2Ha0+7gMze0XP6GHKV7IiZWSz8/OvC0k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749571712; c=relaxed/simple; bh=USwOIsVhkg9+A/PdAnwHxSXCbsHxApVOGy15tnigTpU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YOeNRx/pgdNAmFB2Opt3Nlf3RLt60yUv/lNbvr9INVpEOzvJzrWStO9YRQDZgYntb48QO/kWulhuqW0vQamXa1/2LGJ/ZuWZpZ2YPNhaDL5p2G5t4iysxSVb1x/DkbM3x+y8tz2o1bRANyQabS68CEPdSJ4r0nW7R8IyIXn/pxI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nMzYR96F; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nMzYR96F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42E0FC4CEF0; Tue, 10 Jun 2025 16:08:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749571711; bh=USwOIsVhkg9+A/PdAnwHxSXCbsHxApVOGy15tnigTpU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nMzYR96Fynzp3sQAzKNWvM5Z4VgwmmPLWIhJsUYmsy632UmWgluCPVruUCW6sRvuO s3ZyevWiEH3dmLRdHDKHapVNOpma34dD8NOmucqRnJ20rhQQ+vtuhxLO/OzoOykJxG PNREOVlBcNi4q2tcXQYOr0mn4n+hSmHDY4ngMku0BOwuBhHghpKe7VMvS9uWTsP7tT FnYawbySQa/ft0EgIJ07c5qwF86yMNM0taB/e/FS9EWI9qDEqMP9hgsPfLDs5afBPm +96kG9e0pWOrQoG/K6D4JaZsHW7ffVY/F7JIvQvAQQDGvoT3sCYkoo8g0tvsw88MYI Q7BPA5VdsuAiA== Date: Tue, 10 Jun 2025 16:08:29 +0000 From: Jaegeuk Kim To: Zhiguo Niu Cc: chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, niuzhiguo84@gmail.com, ke.wang@unisoc.com, Hao_hao.Wang@unisoc.com, baocong.liu@unisoc.com Subject: Re: [PATCH v3] f2fs: compress: fix UAF of f2fs_inode_info in f2fs_free_dic Message-ID: References: <1749107920-17958-1-git-send-email-zhiguo.niu@unisoc.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1749107920-17958-1-git-send-email-zhiguo.niu@unisoc.com> Hi Zhiguo, This patch causes CPU hang when running fsstress on compressed/non-compressed files. Please check. On 06/05, Zhiguo Niu wrote: > The decompress_io_ctx may be released asynchronously after > I/O completion. If this file is deleted immediately after read, > and the kworker of processing post_read_wq has not been executed yet > due to high workloads, It is possible that the inode(f2fs_inode_info) > is evicted and freed before it is used f2fs_free_dic. > > The UAF case as below: > Thread A Thread B > - f2fs_decompress_end_io > - f2fs_put_dic > - queue_work > add free_dic work to post_read_wq > - do_unlink > - iput > - evict > - call_rcu > This file is deleted after read. > > Thread C kworker to process post_read_wq > - rcu_do_batch > - f2fs_free_inode > - kmem_cache_free > inode is freed by rcu > - process_scheduled_works > - f2fs_late_free_dic > - f2fs_free_dic > - f2fs_release_decomp_mem > read (dic->inode)->i_compress_algorithm > > This patch use igrab before f2fs_free_dic and iput after free the dic when dic free > action is done by kworker. > > Cc: Daeho Jeong > Fixes: bff139b49d9f ("f2fs: handle decompress only post processing in softirq") > Signed-off-by: Zhiguo Niu > Signed-off-by: Baocong Liu > --- > v3: use igrab to replace __iget > v2: use __iget/iput function > --- > fs/f2fs/compress.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c > index b3c1df9..729ad16 100644 > --- a/fs/f2fs/compress.c > +++ b/fs/f2fs/compress.c > @@ -1687,7 +1687,7 @@ static void f2fs_release_decomp_mem(struct decompress_io_ctx *dic, > } > > static void f2fs_free_dic(struct decompress_io_ctx *dic, > - bool bypass_destroy_callback); > + bool bypass_destroy_callback, bool late_free); > > struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc) > { > @@ -1743,12 +1743,12 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc) > return dic; > > out_free: > - f2fs_free_dic(dic, true); > + f2fs_free_dic(dic, true, false); > return ERR_PTR(ret); > } > > static void f2fs_free_dic(struct decompress_io_ctx *dic, > - bool bypass_destroy_callback) > + bool bypass_destroy_callback, bool late_free) > { > int i; > > @@ -1775,6 +1775,8 @@ static void f2fs_free_dic(struct decompress_io_ctx *dic, > } > > page_array_free(dic->inode, dic->rpages, dic->nr_rpages); > + if (late_free) > + iput(dic->inode); > kmem_cache_free(dic_entry_slab, dic); > } > > @@ -1783,16 +1785,18 @@ static void f2fs_late_free_dic(struct work_struct *work) > struct decompress_io_ctx *dic = > container_of(work, struct decompress_io_ctx, free_work); > > - f2fs_free_dic(dic, false); > + f2fs_free_dic(dic, false, true); > } > > static void f2fs_put_dic(struct decompress_io_ctx *dic, bool in_task) > { > if (refcount_dec_and_test(&dic->refcnt)) { > if (in_task) { > - f2fs_free_dic(dic, false); > + f2fs_free_dic(dic, false, false); > } else { > INIT_WORK(&dic->free_work, f2fs_late_free_dic); > + /* use igrab to avoid inode is evicted simultaneously */ > + f2fs_bug_on(F2FS_I_SB(dic->inode), !igrab(dic->inode)); > queue_work(F2FS_I_SB(dic->inode)->post_read_wq, > &dic->free_work); > } > -- > 1.9.1