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 21A9E1D55C for ; Wed, 4 Oct 2023 18:21:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EbgXtyb7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91C5BC433C7; Wed, 4 Oct 2023 18:21:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696443693; bh=rfnUYRuvf81rl6XEDEwc4+7TZ3vTkyNffQ39DEDj37s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EbgXtyb7/ClbZB6nnOqqWMfnk10F3Ui+Qc7zpMktQnIYACl7/vclNHG8BL4WWxDBM 80KaUXmtv/xTB284DJKtofZ+Q8F671OfK8eEy6gQ2tTcGvTmiP+4OZ9LL2/6HNiSxF KxqO1GLukDPrDfF+tZE+MdKfp9EZoG0k2IrENYGY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pan Bian , Ferry Meng , Ryusuke Konishi , Andrew Morton Subject: [PATCH 6.1 219/259] nilfs2: fix potential use after free in nilfs_gccache_submit_read_data() Date: Wed, 4 Oct 2023 19:56:32 +0200 Message-ID: <20231004175227.370128916@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231004175217.404851126@linuxfoundation.org> References: <20231004175217.404851126@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pan Bian commit 7ee29facd8a9c5a26079148e36bcf07141b3a6bc upstream. In nilfs_gccache_submit_read_data(), brelse(bh) is called to drop the reference count of bh when the call to nilfs_dat_translate() fails. If the reference count hits 0 and its owner page gets unlocked, bh may be freed. However, bh->b_page is dereferenced to put the page after that, which may result in a use-after-free bug. This patch moves the release operation after unlocking and putting the page. NOTE: The function in question is only called in GC, and in combination with current userland tools, address translation using DAT does not occur in that function, so the code path that causes this issue will not be executed. However, it is possible to run that code path by intentionally modifying the userland GC library or by calling the GC ioctl directly. [konishi.ryusuke@gmail.com: NOTE added to the commit log] Link: https://lkml.kernel.org/r/1543201709-53191-1-git-send-email-bianpan2016@163.com Link: https://lkml.kernel.org/r/20230921141731.10073-1-konishi.ryusuke@gmail.com Fixes: a3d93f709e89 ("nilfs2: block cache for garbage collection") Signed-off-by: Pan Bian Reported-by: Ferry Meng Closes: https://lkml.kernel.org/r/20230818092022.111054-1-mengferry@linux.alibaba.com Signed-off-by: Ryusuke Konishi Tested-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/gcinode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/fs/nilfs2/gcinode.c +++ b/fs/nilfs2/gcinode.c @@ -73,10 +73,8 @@ int nilfs_gccache_submit_read_data(struc struct the_nilfs *nilfs = inode->i_sb->s_fs_info; err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn); - if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */ - brelse(bh); + if (unlikely(err)) /* -EIO, -ENOMEM, -ENOENT */ goto failed; - } } lock_buffer(bh); @@ -102,6 +100,8 @@ int nilfs_gccache_submit_read_data(struc failed: unlock_page(bh->b_page); put_page(bh->b_page); + if (unlikely(err)) + brelse(bh); return err; }