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 9680415AD5; Thu, 21 Dec 2023 08:10:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ugsnmhCq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DD26C43391; Thu, 21 Dec 2023 08:10:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1703146217; bh=HIG3brb6PiOIu+YyofIQ2XdvYJ09hzoZ6uochrNHzgo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ugsnmhCq8aXPM5X62dcPH459fRpGsJZAvGGsxy13L4C0wTVsA35ohmbRUlJfJMQpe G8urtwMTFutzUmFs7ohsL+m2TmmiByCj04hGuNQ4dxWLPoseFD++SK0iJDDFKPvV1x +Esk90N9PlrIh1pPu52Vm+xT7B0zxQv2WxLa6FTPBCViP+axTj4eUi4B2OQXvxTdFv rX458ZlgQwyYoqSh0gFjbOy7Cr50I5bFrUxAjKNXXF9EfGl5utvXEB9nw6o3Rs6bBk Wy/J9LmvqJuU9kgE2T5tNB0IDlKpOiIVGHZ6FVcrsfi64JZRsdH55KtM70WIZtUjPb h/936eIba5x9A== Date: Thu, 21 Dec 2023 17:10:13 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: LKML , Linux Trace Kernel , Masami Hiramatsu , Mathieu Desnoyers , Dongliang Cui , Hongyu Jin , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] eventfs: Have event files and directories default to parent uid and gid Message-Id: <20231221171013.05f0d861547caf20982d100a@kernel.org> In-Reply-To: <20231220105017.1489d790@gandalf.local.home> References: <20231220105017.1489d790@gandalf.local.home> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 20 Dec 2023 10:50:17 -0500 Steven Rostedt wrote: > From: "Steven Rostedt (Google)" > > Dongliang reported: > > I found that in the latest version, the nodes of tracefs have been > changed to dynamically created. > > This has caused me to encounter a problem where the gid I specified in > the mounting parameters cannot apply to all files, as in the following > situation: > > /data/tmp/events # mount | grep tracefs > tracefs on /data/tmp type tracefs (rw,seclabel,relatime,gid=3012) > > gid 3012 = readtracefs > > /data/tmp # ls -lh > total 0 > -r--r----- 1 root readtracefs 0 1970-01-01 08:00 README > -r--r----- 1 root readtracefs 0 1970-01-01 08:00 available_events > > ums9621_1h10:/data/tmp/events # ls -lh > total 0 > drwxr-xr-x 2 root root 0 2023-12-19 00:56 alarmtimer > drwxr-xr-x 2 root root 0 2023-12-19 00:56 asoc > > It will prevent certain applications from accessing tracefs properly, I > try to avoid this issue by making the following modifications. > > To fix this, have the files created default to taking the ownership of > the parent dentry unless the ownership was previously set by the user. > > Link: https://lore.kernel.org/linux-trace-kernel/1703063706-30539-1-git-send-email-dongliang.cui@unisoc.com/ > This looks good to me. Acked-by: Masami Hiramatsu (Google) Thank you! > Reported-by: Dongliang Cui > Signed-off-by: Steven Rostedt (Google) > --- > fs/tracefs/event_inode.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c > index 43e237864a42..2ccc849a5bda 100644 > --- a/fs/tracefs/event_inode.c > +++ b/fs/tracefs/event_inode.c > @@ -148,7 +148,8 @@ static const struct file_operations eventfs_file_operations = { > .release = eventfs_release, > }; > > -static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, umode_t mode) > +static void update_inode_attr(struct dentry *dentry, struct inode *inode, > + struct eventfs_attr *attr, umode_t mode) > { > if (!attr) { > inode->i_mode = mode; > @@ -162,9 +163,13 @@ static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, um > > if (attr->mode & EVENTFS_SAVE_UID) > inode->i_uid = attr->uid; > + else > + inode->i_uid = d_inode(dentry->d_parent)->i_uid; > > if (attr->mode & EVENTFS_SAVE_GID) > inode->i_gid = attr->gid; > + else > + inode->i_gid = d_inode(dentry->d_parent)->i_gid; > } > > /** > @@ -206,7 +211,7 @@ static struct dentry *create_file(const char *name, umode_t mode, > return eventfs_failed_creating(dentry); > > /* If the user updated the directory's attributes, use them */ > - update_inode_attr(inode, attr, mode); > + update_inode_attr(dentry, inode, attr, mode); > > inode->i_op = &eventfs_file_inode_operations; > inode->i_fop = fop; > @@ -242,7 +247,8 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent > return eventfs_failed_creating(dentry); > > /* If the user updated the directory's attributes, use them */ > - update_inode_attr(inode, &ei->attr, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); > + update_inode_attr(dentry, inode, &ei->attr, > + S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); > > inode->i_op = &eventfs_root_dir_inode_operations; > inode->i_fop = &eventfs_file_operations; > -- > 2.42.0 > -- Masami Hiramatsu (Google)