diff mbox series

eventfs: Have event files and directories default to parent uid and gid

Message ID 20231220105017.1489d790@gandalf.local.home (mailing list archive)
State Accepted
Commit 0dfc852b6fe3cbecbea67332a0dce2bebeba540d
Headers show
Series eventfs: Have event files and directories default to parent uid and gid | expand

Commit Message

Steven Rostedt Dec. 20, 2023, 3:50 p.m. UTC 
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

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/

Reported-by: Dongliang Cui <cuidongliang390@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 fs/tracefs/event_inode.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Comments

Steven Rostedt Dec. 20, 2023, 4:13 p.m. UTC | #1 
On Wed, 20 Dec 2023 10:50:17 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> 
> 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/
> 

I forgot to add:

  Cc: stable@vger.kernel.org
  Fixes: 28e12c09f5aa0 ("eventfs: Save ownership and mode")


-- Steve

> Reported-by: Dongliang Cui <cuidongliang390@gmail.com>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>  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;
Masami Hiramatsu (Google) Dec. 21, 2023, 8:10 a.m. UTC | #2 
On Wed, 20 Dec 2023 10:50:17 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> 
> 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) <mhiramat@kernel.org>

Thank you!

> Reported-by: Dongliang Cui <cuidongliang390@gmail.com>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>  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
>
diff mbox series

Patch

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;