From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pan Bian , Andrew Morton , Mark Fasheh , Joel Becker , Junxiao Bi , Joseph Qi , Changwei Ge , Linus Torvalds , Sasha Levin Subject: [PATCH 4.19 132/142] ocfs2: fix potential use after free Date: Fri, 14 Dec 2018 13:00:17 +0100 Message-Id: <20181214115752.319078972@linuxfoundation.org> In-Reply-To: <20181214115747.053633987@linuxfoundation.org> References: <20181214115747.053633987@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit List-ID: 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 164f7e586739d07eb56af6f6d66acebb11f315c8 ] ocfs2_get_dentry() calls iput(inode) to drop the reference count of inode, and if the reference count hits 0, inode is freed. However, in this function, it then reads inode->i_generation, which may result in a use after free bug. Move the put operation later. Link: http://lkml.kernel.org/r/1543109237-110227-1-git-send-email-bianpan2016@163.com Fixes: 781f200cb7a("ocfs2: Remove masklog ML_EXPORT.") Signed-off-by: Pan Bian Reviewed-by: Andrew Morton Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Joseph Qi Cc: Changwei Ge Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/ocfs2/export.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/ocfs2/export.c +++ b/fs/ocfs2/export.c @@ -125,10 +125,10 @@ check_err: check_gen: if (handle->ih_generation != inode->i_generation) { - iput(inode); trace_ocfs2_get_dentry_generation((unsigned long long)blkno, handle->ih_generation, inode->i_generation); + iput(inode); result = ERR_PTR(-ESTALE); goto bail; }