[apparmor] [PATCH 1/4] AppArmor: refactor securityfs to use structures

[John Johansen]

On 12/31/2011 02:22 PM, Kees Cook wrote:
> Use a file tree structure to represent the AppArmor securityfs.
>
> Signed-off-by: Kees Cook<kees at ubuntu.com>
Acked-by: John Johansen <john.johansen at canonical.com>

> ---
>   security/apparmor/apparmorfs.c         |  132 ++++++++++++++++++++++----------
>   security/apparmor/include/apparmorfs.h |   24 ++++++
>   2 files changed, 114 insertions(+), 42 deletions(-)
>
> diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
> index 0848292..07fd060 100644
> --- a/security/apparmor/apparmorfs.c
> +++ b/security/apparmor/apparmorfs.c
> @@ -144,36 +144,103 @@ static const struct file_operations aa_fs_profile_remove = {
>
>   /** Base file system setup **/
>
> -static struct dentry *aa_fs_dentry __initdata;
> +static struct aa_fs_entry aa_fs_entry_apparmor[] = {
> +	AA_FS_FILE_FOPS(".load", 0640,&aa_fs_profile_load),
> +	AA_FS_FILE_FOPS(".replace", 0640,&aa_fs_profile_replace),
> +	AA_FS_FILE_FOPS(".remove", 0640,&aa_fs_profile_remove),
> +	{ }
> +};
>
> -static void __init aafs_remove(const char *name)
> -{
> -	struct dentry *dentry;
> +static struct aa_fs_entry aa_fs_entry =
> +	AA_FS_DIR("apparmor", aa_fs_entry_apparmor);
>
> -	dentry = lookup_one_len(name, aa_fs_dentry, strlen(name));
> -	if (!IS_ERR(dentry)) {
> -		securityfs_remove(dentry);
> -		dput(dentry);
> +/**
> + * aafs_create_file - create a file entry in the apparmor securityfs
> + * @fs_file: aa_fs_entry to build an entry for (NOT NULL)
> + * @parent: the parent dentry in the securityfs
> + *
> + * Use aafs_remove_file to remove entries created with this fn.
> + */
> +static int __init aafs_create_file(struct aa_fs_entry *fs_file,
> +				   struct dentry *parent)
> +{
> +	int error = 0;
> +
> +	fs_file->dentry = securityfs_create_file(fs_file->name,
> +						 S_IFREG | fs_file->mode,
> +						 parent, fs_file,
> +						 fs_file->file_ops);
> +	if (IS_ERR(fs_file->dentry)) {
> +		error = PTR_ERR(fs_file->dentry);
> +		fs_file->dentry = NULL;
>   	}
> +	return error;
>   }
>
>   /**
> - * aafs_create - create an entry in the apparmor filesystem
> - * @name: name of the entry (NOT NULL)
> - * @mask: file permission mask of the file
> - * @fops: file operations for the file (NOT NULL)
> + * aafs_create_dir - recursively create a directory entry in the securityfs
> + * @fs_dir: aa_fs_entry (and all child entries) to build (NOT NULL)
> + * @parent: the parent dentry in the securityfs
>    *
> - * Used aafs_remove to remove entries created with this fn.
> + * Use aafs_remove_dir to remove entries created with this fn.
>    */
> -static int __init aafs_create(const char *name, int mask,
> -			      const struct file_operations *fops)
> +static int __init aafs_create_dir(struct aa_fs_entry *fs_dir,
> +				  struct dentry *parent)
>   {
> -	struct dentry *dentry;
> +	int error;
> +	struct aa_fs_entry *fs_file;
>
> -	dentry = securityfs_create_file(name, S_IFREG | mask, aa_fs_dentry,
> -					NULL, fops);
> +	fs_dir->dentry = securityfs_create_dir(fs_dir->name, parent);
> +	if (IS_ERR(fs_dir->dentry)) {
> +		error = PTR_ERR(fs_dir->dentry);
> +		fs_dir->dentry = NULL;
> +		goto failed;
> +	}
>
> -	return IS_ERR(dentry) ? PTR_ERR(dentry) : 0;
> +	for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) {
> +		if (fs_file->v_type == AA_FS_TYPE_DIR)
> +			error = aafs_create_dir(fs_file, fs_dir->dentry);
> +		else
> +			error = aafs_create_file(fs_file, fs_dir->dentry);
> +		if (error)
> +			goto failed;
> +	}
> +
> +	return 0;
> +
> +failed:
> +	return error;
> +}
> +
> +/**
> + * aafs_remove_file - drop a single file entry in the apparmor securityfs
> + * @fs_file: aa_fs_entry to detach from the securityfs (NOT NULL)
> + */
> +static void __init aafs_remove_file(struct aa_fs_entry *fs_file)
> +{
> +	if (!fs_file->dentry)
> +		return;
> +
> +	securityfs_remove(fs_file->dentry);
> +	fs_file->dentry = NULL;
> +}
> +
> +/**
> + * aafs_remove_dir - recursively drop a directory entry from the securityfs
> + * @fs_dir: aa_fs_entry (and all child entries) to detach (NOT NULL)
> + */
> +static void __init aafs_remove_dir(struct aa_fs_entry *fs_dir)
> +{
> +	struct aa_fs_entry *fs_file;
> +
> +	for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) {
> +		if (fs_file->v_type == AA_FS_TYPE_DIR)
> +			aafs_remove_dir(fs_file);
> +		else
> +			aafs_remove_file(fs_file);
> +	}
> +
> +	aafs_remove_file(fs_dir);
>   }
>
>   /**
> @@ -183,14 +250,7 @@ static int __init aafs_create(const char *name, int mask,
>    */
>   void __init aa_destroy_aafs(void)
>   {
> -	if (aa_fs_dentry) {
> -		aafs_remove(".remove");
> -		aafs_remove(".replace");
> -		aafs_remove(".load");
> -
> -		securityfs_remove(aa_fs_dentry);
> -		aa_fs_dentry = NULL;
> -	}
> +	aafs_remove_dir(&aa_fs_entry);
>   }
>
>   /**
> @@ -207,25 +267,13 @@ int __init aa_create_aafs(void)
>   	if (!apparmor_initialized)
>   		return 0;
>
> -	if (aa_fs_dentry) {
> +	if (aa_fs_entry.dentry) {
>   		AA_ERROR("%s: AppArmor securityfs already exists\n", __func__);
>   		return -EEXIST;
>   	}
>
> -	aa_fs_dentry = securityfs_create_dir("apparmor", NULL);
> -	if (IS_ERR(aa_fs_dentry)) {
> -		error = PTR_ERR(aa_fs_dentry);
> -		aa_fs_dentry = NULL;
> -		goto error;
> -	}
> -
> -	error = aafs_create(".load", 0640,&aa_fs_profile_load);
> -	if (error)
> -		goto error;
> -	error = aafs_create(".replace", 0640,&aa_fs_profile_replace);
> -	if (error)
> -		goto error;
> -	error = aafs_create(".remove", 0640,&aa_fs_profile_remove);
> +	/* Populate fs tree. */
> +	error = aafs_create_dir(&aa_fs_entry, NULL);
>   	if (error)
>   		goto error;
>
> diff --git a/security/apparmor/include/apparmorfs.h b/security/apparmor/include/apparmorfs.h
> index cb1e93a..0e72fa0 100644
> --- a/security/apparmor/include/apparmorfs.h
> +++ b/security/apparmor/include/apparmorfs.h
> @@ -15,6 +15,30 @@
>   #ifndef __AA_APPARMORFS_H
>   #define __AA_APPARMORFS_H
>
> +enum aa_fs_type {
> +	AA_FS_TYPE_FOPS,
> +	AA_FS_TYPE_DIR,
> +};
> +
> +struct aa_fs_entry;
> +
> +struct aa_fs_entry {
> +	const char *name;
> +	struct dentry *dentry;
> +	int mode;
> +	enum aa_fs_type v_type;
> +	union {
> +		struct aa_fs_entry *files;
> +	} v;
> +	const struct file_operations *file_ops;
> +};
> +
> +#define AA_FS_FILE_FOPS(_name, _mode, _fops) \
> +	{ .name = (_name), .v_type = AA_FS_TYPE_FOPS, \
> +	  .mode = (_mode), .file_ops = (_fops) }
> +#define AA_FS_DIR(_name, _value) \
> +	{ .name = (_name), .v_type = AA_FS_TYPE_DIR, .v.files = (_value) }
> +
>   extern void __init aa_destroy_aafs(void);
>
>   #endif /* __AA_APPARMORFS_H */