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 827C71A28D for ; Wed, 11 Jun 2025 06:07:05 +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=1749622026; cv=none; b=tdXDoeMdaXotJfBxSGessqJCCzTRiwVux9cwTfRT6A6AGToIZQGDmCnzAC4elIgPAkzayJHcuN1mAQvVHvUqh4sWw9ZeNaTy71Gtz6eU4SGvg0j1STTssLYaBGp+OjbAHDJ/600T7XjeW6EI7G+g4DJF2He/MbYv2SNVVfFuuVY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749622026; c=relaxed/simple; bh=XvaWqgGFHD8E8hWRNsclo9DOi2AH3hXAefuTklKXJ0Q=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=jtNmbncjcoYYQJ4Rzo5Y65srTeqPn0bx0bWIv1L3CuJkqb+rX7W3B4VHL+HDXAHbL+UtYDAK8X6JyhmXU7PELm5MdyXaZyQtoEsCLcuxjgSrlUUnYcSiDbOurV8vcAhMAYz8Zv2Kw8EWiDxRA2mfAa64IW/Qc4g+65uRTektdN4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=vCQujmde; 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="vCQujmde" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B9D5C4CEEE; Wed, 11 Jun 2025 06:07:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749622025; bh=XvaWqgGFHD8E8hWRNsclo9DOi2AH3hXAefuTklKXJ0Q=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=vCQujmdeOR+5Aa5t8311gviiz/aJCqpq5LQI4Yi3NmRDsd0I9v5bVZimVid/PF3+q spIcQ37kz2xGU+ur+ZinkqxRCyh+2KFtrWICYo7e2zKUG/FhS77RqXKyOLVQntyRot fMiOujf3czYCIy8LICRdhYQ/2Rqpbf07J9U6SwVz1UB0S3134+5XT1ztflmcdiWFh+ sjIfKUL0vc42o3QmmSpJpIYijaNcuS0xJK1kP+e3GQyLzAvxeYxKNtuxbncXi4EMqp 10Da87xwNiQCqJ56I2sZs+7qMN2z6Lgv6v2p8Ph5p2EPYuTQRMLmQqnBQBzscbC1sp YeeaWHaP3diqA== Message-ID: <5c1da066-0c76-42f4-8c46-a99f60a900bf@kernel.org> Date: Wed, 11 Jun 2025 14:07:01 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird 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 To: Jaegeuk Kim , Zhiguo Niu References: <1749107920-17958-1-git-send-email-zhiguo.niu@unisoc.com> Content-Language: en-US From: Chao Yu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/11/25 00:08, Jaegeuk Kim wrote: > Hi Zhiguo, > > This patch causes CPU hang when running fsstress on compressed/non-compressed > files. Please check. Oh, seems it may cause below deadlock: CPU0 process A - spin_lock(i_lock) software IRQ - end_io - igrab - spin_lock(i_lock) Thanks, > > 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