Re: [PATCH v4 1/3] fanotify: introduce new event type FAN_OPEN_EXEC

[Matthew Bobrowski <mbobrowski@mbobrowski.org>]

On Tue, Oct 16, 2018 at 01:58:32PM +0200, Jan Kara wrote:
> On Thu 11-10-18 21:42:23, Matthew Bobrowski wrote:
> > A new event type FAN_OPEN_EXEC has been defined so that users have the
> > ability to receive events specifically when a file has been opened with
> > the intent to be executed.
> 
> Can we perhaps expand this a bit to clarify that this means execve(),
> execve_at(), and uselib() syscalls? Then the sentence below could just
> clarify that feature is implemented by fanotify_open() generating
> FAN_OPEN_EXEC event if __FMODE_EXEC is set within file->f_flags. Thanks!

Updated.

I will include these updates within the new patch series I'm going to post
through.

> > The FAN_OPEN_EXEC flag is set within the fsnotify_open() hook only if a
> > file has the __FMODE_EXEC bit set within file->f_flags.
> > 
> > Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
> > ---
> >  fs/notify/fanotify/fanotify.c    | 3 ++-
> >  fs/notify/fsnotify.c             | 2 +-
> >  include/linux/fanotify.h         | 2 +-
> >  include/linux/fsnotify.h         | 2 ++
> >  include/linux/fsnotify_backend.h | 7 +++++--
> >  include/uapi/linux/fanotify.h    | 1 +
> >  6 files changed, 12 insertions(+), 5 deletions(-)
> > 
> > diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> > index 2c57186caa2e..b3e92302ed84 100644
> > --- a/fs/notify/fanotify/fanotify.c
> > +++ b/fs/notify/fanotify/fanotify.c
> > @@ -207,8 +207,9 @@ static int fanotify_handle_event(struct fsnotify_group *group,
> >  	BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM);
> >  	BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM);
> >  	BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR);
> > +	BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC);
> >  
> > -	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 10);
> > +	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 11);
> >  
> >  	if (!fanotify_should_send_event(iter_info, mask, data, data_type))
> >  		return 0;
> > diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> > index a0ad06285450..051e5fc0dba1 100644
> > --- a/fs/notify/fsnotify.c
> > +++ b/fs/notify/fsnotify.c
> > @@ -402,7 +402,7 @@ static __init int fsnotify_init(void)
> >  {
> >  	int ret;
> >  
> > -	BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 23);
> > +	BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 24);
> >  
> >  	ret = init_srcu_struct(&fsnotify_mark_srcu);
> >  	if (ret)
> > diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
> > index 05b696b4856b..0e07d23b6c17 100644
> > --- a/include/linux/fanotify.h
> > +++ b/include/linux/fanotify.h
> > @@ -39,7 +39,7 @@
> >  
> >  /* Events that user can request to be notified on */
> >  #define FANOTIFY_EVENTS		(FAN_ACCESS | FAN_MODIFY | \
> > -				 FAN_CLOSE | FAN_OPEN)
> > +				 FAN_CLOSE | FAN_OPEN | FAN_OPEN_EXEC)
> >  
> >  /* Events that require a permission response from user */
> >  #define FANOTIFY_PERM_EVENTS	(FAN_OPEN_PERM | FAN_ACCESS_PERM)
> > diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> > index fd1ce10553bf..1fe5ac93b252 100644
> > --- a/include/linux/fsnotify.h
> > +++ b/include/linux/fsnotify.h
> > @@ -215,6 +215,8 @@ static inline void fsnotify_open(struct file *file)
> >  
> >  	if (S_ISDIR(inode->i_mode))
> >  		mask |= FS_ISDIR;
> > +	if (file->f_flags & __FMODE_EXEC)
> > +		mask |= FS_OPEN_EXEC;
> >  
> >  	fsnotify_parent(path, NULL, mask);
> >  	fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
> > diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> > index 135b973e44d1..329ac6684326 100644
> > --- a/include/linux/fsnotify_backend.h
> > +++ b/include/linux/fsnotify_backend.h
> > @@ -38,6 +38,7 @@
> >  #define FS_DELETE		0x00000200	/* Subfile was deleted */
> >  #define FS_DELETE_SELF		0x00000400	/* Self was deleted */
> >  #define FS_MOVE_SELF		0x00000800	/* Self was moved */
> > +#define FS_OPEN_EXEC		0x00001000	/* File was opened for exec */
> >  
> >  #define FS_UNMOUNT		0x00002000	/* inode on umount fs */
> >  #define FS_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
> > @@ -62,7 +63,8 @@
> >  #define FS_EVENTS_POSS_ON_CHILD   (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
> >  				   FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\
> >  				   FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
> > -				   FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM)
> > +				   FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM |\
> > +				   FS_OPEN_EXEC)
> >  
> >  #define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)
> >  
> > @@ -74,7 +76,8 @@
> >  			     FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
> >  			     FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
> >  			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
> > -			     FS_OPEN_PERM | FS_ACCESS_PERM | FS_DN_RENAME)
> > +			     FS_OPEN_PERM | FS_ACCESS_PERM | FS_DN_RENAME |\
> > +			     FS_OPEN_EXEC)
> >  
> >  /* Extra flags that may be reported with event or control handling of events */
> >  #define ALL_FSNOTIFY_FLAGS  (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \
> > diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
> > index 00b2304ed124..da278f11ab29 100644
> > --- a/include/uapi/linux/fanotify.h
> > +++ b/include/uapi/linux/fanotify.h
> > @@ -10,6 +10,7 @@
> >  #define FAN_CLOSE_WRITE		0x00000008	/* Writtable file closed */
> >  #define FAN_CLOSE_NOWRITE	0x00000010	/* Unwrittable file closed */
> >  #define FAN_OPEN		0x00000020	/* File was opened */
> > +#define FAN_OPEN_EXEC		0x00001000	/* File was opened for exec */
> >  
> >  #define FAN_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
> >  
> > -- 
> > 2.17.2
> > 
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR