Re: [RFC v6 01/40] vfs: Add IS_ACL() and IS_RICHACL() tests

[J. Bruce Fields]

On Tue, Aug 04, 2015 at 01:52:59PM +0200, Andreas Gruenbacher wrote:
> The vfs does not apply the umask for file systems that support acls. The
> test used for this used to be called IS_POSIXACL(). Switch to a new
> IS_ACL() test to check for either posix acls or richacls instead. Add a new
> MS_RICHACL flag and IS_RICHACL() test for richacls alone. The IS_POSIXACL()
> test is still needed by file systems that specifically support POSIX ACLs,
> like nfsd.

Nit: nfsd's not a filesystem.  Maybe just list the users instead.

--b.

> 
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> ---
>  fs/Kconfig              |  3 +++
>  fs/namei.c              |  8 ++++----
>  include/linux/fs.h      | 12 ++++++++++++
>  include/uapi/linux/fs.h |  3 ++-
>  4 files changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 011f433..3e09c06 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -59,6 +59,9 @@ endif # BLOCK
>  config FS_POSIX_ACL
>  	def_bool n
>  
> +config FS_RICHACL
> +	def_bool n
> +
>  config EXPORTFS
>  	tristate
>  
> diff --git a/fs/namei.c b/fs/namei.c
> index fbbcf09..8f3db24 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -2771,7 +2771,7 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
>  	}
>  
>  	mode = op->mode;
> -	if ((open_flag & O_CREAT) && !IS_POSIXACL(dir))
> +	if ((open_flag & O_CREAT) && !IS_ACL(dir))
>  		mode &= ~current_umask();
>  
>  	excl = (open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT);
> @@ -2955,7 +2955,7 @@ static int lookup_open(struct nameidata *nd, struct path *path,
>  	/* Negative dentry, just create the file */
>  	if (!dentry->d_inode && (op->open_flag & O_CREAT)) {
>  		umode_t mode = op->mode;
> -		if (!IS_POSIXACL(dir->d_inode))
> +		if (!IS_ACL(dir->d_inode))
>  			mode &= ~current_umask();
>  		/*
>  		 * This write is needed to ensure that a
> @@ -3526,7 +3526,7 @@ retry:
>  	if (IS_ERR(dentry))
>  		return PTR_ERR(dentry);
>  
> -	if (!IS_POSIXACL(path.dentry->d_inode))
> +	if (!IS_ACL(path.dentry->d_inode))
>  		mode &= ~current_umask();
>  	error = security_path_mknod(&path, dentry, mode, dev);
>  	if (error)
> @@ -3595,7 +3595,7 @@ retry:
>  	if (IS_ERR(dentry))
>  		return PTR_ERR(dentry);
>  
> -	if (!IS_POSIXACL(path.dentry->d_inode))
> +	if (!IS_ACL(path.dentry->d_inode))
>  		mode &= ~current_umask();
>  	error = security_path_mkdir(&path, dentry, mode);
>  	if (!error)
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index cc008c3..44e696e 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1770,6 +1770,12 @@ struct super_operations {
>  #define IS_IMMUTABLE(inode)	((inode)->i_flags & S_IMMUTABLE)
>  #define IS_POSIXACL(inode)	__IS_FLG(inode, MS_POSIXACL)
>  
> +#ifdef CONFIG_FS_RICHACL
> +#define IS_RICHACL(inode)	__IS_FLG(inode, MS_RICHACL)
> +#else
> +#define IS_RICHACL(inode)	0
> +#endif
> +
>  #define IS_DEADDIR(inode)	((inode)->i_flags & S_DEAD)
>  #define IS_NOCMTIME(inode)	((inode)->i_flags & S_NOCMTIME)
>  #define IS_SWAPFILE(inode)	((inode)->i_flags & S_SWAPFILE)
> @@ -1783,6 +1789,12 @@ struct super_operations {
>  				 (inode)->i_rdev == WHITEOUT_DEV)
>  
>  /*
> + * IS_ACL() tells the VFS to not apply the umask
> + * and use check_acl for acl permission checks when defined.
> + */
> +#define IS_ACL(inode)		__IS_FLG(inode, MS_POSIXACL | MS_RICHACL)
> +
> +/*
>   * Inode state bits.  Protected by inode->i_lock
>   *
>   * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index 9b964a5..6ac6bc9 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -81,7 +81,7 @@ struct inodes_stat_t {
>  #define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
>  				   MS_VERBOSE is deprecated. */
>  #define MS_SILENT	32768
> -#define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
> +#define MS_POSIXACL	(1<<16)	/* Supports POSIX ACLs */
>  #define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
>  #define MS_PRIVATE	(1<<18)	/* change to private */
>  #define MS_SLAVE	(1<<19)	/* change to slave */
> @@ -91,6 +91,7 @@ struct inodes_stat_t {
>  #define MS_I_VERSION	(1<<23) /* Update inode I_version field */
>  #define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
>  #define MS_LAZYTIME	(1<<25) /* Update the on-disk [acm]times lazily */
> +#define MS_RICHACL	(1<<26) /* Supports richacls */
>  
>  /* These sb flags are internal to the kernel */
>  #define MS_NOSEC	(1<<28)
> -- 
> 2.5.0
> 
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