diff options
| -rw-r--r-- | include/linux/security.h | 12 | ||||
| -rw-r--r-- | security/inode.c | 144 |
2 files changed, 135 insertions, 21 deletions
diff --git a/include/linux/security.h b/include/linux/security.h index af675b576645..caf8b64d8b5c 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1651,6 +1651,10 @@ extern struct dentry *securityfs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops); extern struct dentry *securityfs_create_dir(const char *name, struct dentry *parent); +struct dentry *securityfs_create_symlink(const char *name, + struct dentry *parent, + const char *target, + const struct inode_operations *iops); extern void securityfs_remove(struct dentry *dentry); #else /* CONFIG_SECURITYFS */ @@ -1670,6 +1674,14 @@ static inline struct dentry *securityfs_create_file(const char *name, return ERR_PTR(-ENODEV); } +static inline struct dentry *securityfs_create_symlink(const char *name, + struct dentry *parent, + const char *target, + const struct inode_operations *iops) +{ + return ERR_PTR(-ENODEV); +} + static inline void securityfs_remove(struct dentry *dentry) {} diff --git a/security/inode.c b/security/inode.c index eccd58ef2ae8..8dd9ca8848e4 100644 --- a/security/inode.c +++ b/security/inode.c @@ -26,11 +26,31 @@ static struct vfsmount *mount; static int mount_count; +static void securityfs_evict_inode(struct inode *inode) +{ + truncate_inode_pages_final(&inode->i_data); + clear_inode(inode); + if (S_ISLNK(inode->i_mode)) + kfree(inode->i_link); +} + +static const struct super_operations securityfs_super_operations = { + .statfs = simple_statfs, + .evict_inode = securityfs_evict_inode, +}; + static int fill_super(struct super_block *sb, void *data, int silent) { static const struct tree_descr files[] = {{""}}; + int error; + + error = simple_fill_super(sb, SECURITYFS_MAGIC, files); + if (error) + return error; + + sb->s_op = &securityfs_super_operations; - return simple_fill_super(sb, SECURITYFS_MAGIC, files); + return 0; } static struct dentry *get_sb(struct file_system_type *fs_type, @@ -48,7 +68,7 @@ static struct file_system_type fs_type = { }; /** - * securityfs_create_file - create a file in the securityfs filesystem + * securityfs_create_dentry - create a dentry in the securityfs filesystem * * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have @@ -60,34 +80,35 @@ static struct file_system_type fs_type = { * the open() call. * @fops: a pointer to a struct file_operations that should be used for * this file. + * @iops: a point to a struct of inode_operations that should be used for + * this file/dir * - * This is the basic "create a file" function for securityfs. It allows for a - * wide range of flexibility in creating a file, or a directory (if you - * want to create a directory, the securityfs_create_dir() function is - * recommended to be used instead). + * This is the basic "create a file/dir/symlink" function for + * securityfs. It allows for a wide range of flexibility in creating + * a file, or a directory (if you want to create a directory, the + * securityfs_create_dir() function is recommended to be used + * instead). * * This function returns a pointer to a dentry if it succeeds. This - * pointer must be passed to the securityfs_remove() function when the file is - * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here). If an error occurs, the function will return - * the error value (via ERR_PTR). + * pointer must be passed to the securityfs_remove() function when the + * file is to be removed (no automatic cleanup happens if your module + * is unloaded, you are responsible here). If an error occurs, the + * function will return the error value (via ERR_PTR). * * If securityfs is not enabled in the kernel, the value %-ENODEV is * returned. */ -struct dentry *securityfs_create_file(const char *name, umode_t mode, - struct dentry *parent, void *data, - const struct file_operations *fops) +static struct dentry *securityfs_create_dentry(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops, + const struct inode_operations *iops) { struct dentry *dentry; - int is_dir = S_ISDIR(mode); struct inode *dir, *inode; int error; - if (!is_dir) { - BUG_ON(!fops); + if (!(mode & S_IFMT)) mode = (mode & S_IALLUGO) | S_IFREG; - } pr_debug("securityfs: creating file '%s'\n",name); @@ -120,11 +141,14 @@ struct dentry *securityfs_create_file(const char *name, umode_t mode, inode->i_mode = mode; inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); inode->i_private = data; - if (is_dir) { + if (S_ISDIR(mode)) { inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; inc_nlink(inode); inc_nlink(dir); + } else if (S_ISLNK(mode)) { + inode->i_op = iops ? iops : &simple_symlink_inode_operations; + inode->i_link = data; } else { inode->i_fop = fops; } @@ -141,6 +165,38 @@ out: simple_release_fs(&mount, &mount_count); return dentry; } + +/** + * securityfs_create_file - create a file in the securityfs filesystem + * + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the securityfs filesystem. + * @data: a pointer to something that the caller will want to get to later + * on. The inode.i_private pointer will point to this value on + * the open() call. + * @fops: a pointer to a struct file_operations that should be used for + * this file. + * + * This function creates a file in securityfs with the given @name. + * + * This function returns a pointer to a dentry if it succeeds. This + * pointer must be passed to the securityfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here). If an error occurs, the function will return + * the error value (via ERR_PTR). + * + * If securityfs is not enabled in the kernel, the value %-ENODEV is + * returned. + */ +struct dentry *securityfs_create_file(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops) +{ + return securityfs_create_dentry(name, mode, parent, data, fops, NULL); +} EXPORT_SYMBOL_GPL(securityfs_create_file); /** @@ -165,13 +221,59 @@ EXPORT_SYMBOL_GPL(securityfs_create_file); */ struct dentry *securityfs_create_dir(const char *name, struct dentry *parent) { - return securityfs_create_file(name, - S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, - parent, NULL, NULL); + return securityfs_create_file(name, S_IFDIR | 0755, parent, NULL, NULL); } EXPORT_SYMBOL_GPL(securityfs_create_dir); /** + * securityfs_create_symlink - create a symlink in the securityfs filesystem + * + * @name: a pointer to a string containing the name of the symlink to + * create. + * @parent: a pointer to the parent dentry for the symlink. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * directory will be created in the root of the securityfs filesystem. + * @target: a pointer to a string containing the name of the symlink's target. + * If this parameter is %NULL, then the @iops parameter needs to be + * setup to handle .readlink and .get_link inode_operations. + * @iops: a pointer to the struct inode_operations to use for the symlink. If + * this parameter is %NULL, then the default simple_symlink_inode + * operations will be used. + * + * This function creates a symlink in securityfs with the given @name. + * + * This function returns a pointer to a dentry if it succeeds. This + * pointer must be passed to the securityfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here). If an error occurs, the function will return + * the error value (via ERR_PTR). + * + * If securityfs is not enabled in the kernel, the value %-ENODEV is + * returned. + */ +struct dentry *securityfs_create_symlink(const char *name, + struct dentry *parent, + const char *target, + const struct inode_operations *iops) +{ + struct dentry *dent; + char *link = NULL; + + if (target) { + link = kstrdup(target, GFP_KERNEL); + if (!link) + return ERR_PTR(-ENOMEM); + } + dent = securityfs_create_dentry(name, S_IFLNK | 0444, parent, + link, NULL, iops); + if (IS_ERR(dent)) + kfree(link); + + return dent; +} +EXPORT_SYMBOL_GPL(securityfs_create_symlink); + +/** * securityfs_remove - removes a file or directory from the securityfs filesystem * * @dentry: a pointer to a the dentry of the file or directory to be removed. |