diff options
Diffstat (limited to 'security/apparmor/apparmorfs.c')
| -rw-r--r-- | security/apparmor/apparmorfs.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c new file mode 100644 index 00000000000..7320331b44a --- /dev/null +++ b/security/apparmor/apparmorfs.c @@ -0,0 +1,239 @@ +/* + * AppArmor security module + * + * This file contains AppArmor /sys/kernel/security/apparmor interface functions + * + * Copyright (C) 1998-2008 Novell/SUSE + * Copyright 2009-2010 Canonical Ltd. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + */ + +#include <linux/security.h> +#include <linux/vmalloc.h> +#include <linux/module.h> +#include <linux/seq_file.h> +#include <linux/uaccess.h> +#include <linux/namei.h> + +#include "include/apparmor.h" +#include "include/apparmorfs.h" +#include "include/audit.h" +#include "include/context.h" +#include "include/policy.h" + +/** + * aa_simple_write_to_buffer - common routine for getting policy from user + * @op: operation doing the user buffer copy + * @userbuf: user buffer to copy data from (NOT NULL) + * @alloc_size: size of user buffer + * @copy_size: size of data to copy from user buffer + * @pos: position write is at in the file (NOT NULL) + * + * Returns: kernel buffer containing copy of user buffer data or an + * ERR_PTR on failure. + */ +static char *aa_simple_write_to_buffer(int op, const char __user *userbuf, + size_t alloc_size, size_t copy_size, + loff_t *pos) +{ + char *data; + + if (*pos != 0) + /* only writes from pos 0, that is complete writes */ + return ERR_PTR(-ESPIPE); + + /* + * Don't allow profile load/replace/remove from profiles that don't + * have CAP_MAC_ADMIN + */ + if (!aa_may_manage_policy(op)) + return ERR_PTR(-EACCES); + + /* freed by caller to simple_write_to_buffer */ + data = kvmalloc(alloc_size); + if (data == NULL) + return ERR_PTR(-ENOMEM); + + if (copy_from_user(data, userbuf, copy_size)) { + kvfree(data); + return ERR_PTR(-EFAULT); + } + + return data; +} + + +/* .load file hook fn to load policy */ +static ssize_t profile_load(struct file *f, const char __user *buf, size_t size, + loff_t *pos) +{ + char *data; + ssize_t error; + + data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos); + + error = PTR_ERR(data); + if (!IS_ERR(data)) { + error = aa_replace_profiles(data, size, PROF_ADD); + kvfree(data); + } + + return error; +} + +static const struct file_operations aa_fs_profile_load = { + .write = profile_load +}; + +/* .replace file hook fn to load and/or replace policy */ +static ssize_t profile_replace(struct file *f, const char __user *buf, + size_t size, loff_t *pos) +{ + char *data; + ssize_t error; + + data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos); + error = PTR_ERR(data); + if (!IS_ERR(data)) { + error = aa_replace_profiles(data, size, PROF_REPLACE); + kvfree(data); + } + + return error; +} + +static const struct file_operations aa_fs_profile_replace = { + .write = profile_replace +}; + +/* .remove file hook fn to remove loaded policy */ +static ssize_t profile_remove(struct file *f, const char __user *buf, + size_t size, loff_t *pos) +{ + char *data; + ssize_t error; + + /* + * aa_remove_profile needs a null terminated string so 1 extra + * byte is allocated and the copied data is null terminated. + */ + data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos); + + error = PTR_ERR(data); + if (!IS_ERR(data)) { + data[size] = 0; + error = aa_remove_profiles(data, size); + kvfree(data); + } + + return error; +} + +static const struct file_operations aa_fs_profile_remove = { + .write = profile_remove +}; + +/** Base file system setup **/ + +static struct dentry *aa_fs_dentry __initdata; + +static void __init aafs_remove(const char *name) +{ + struct dentry *dentry; + + dentry = lookup_one_len(name, aa_fs_dentry, strlen(name)); + if (!IS_ERR(dentry)) { + securityfs_remove(dentry); + dput(dentry); + } +} + +/** + * 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) + * + * Used aafs_remove to remove entries created with this fn. + */ +static int __init aafs_create(const char *name, int mask, + const struct file_operations *fops) +{ + struct dentry *dentry; + + dentry = securityfs_create_file(name, S_IFREG | mask, aa_fs_dentry, + NULL, fops); + + return IS_ERR(dentry) ? PTR_ERR(dentry) : 0; +} + +/** + * aa_destroy_aafs - cleanup and free aafs + * + * releases dentries allocated by aa_create_aafs + */ +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; + } +} + +/** + * aa_create_aafs - create the apparmor security filesystem + * + * dentries created here are released by aa_destroy_aafs + * + * Returns: error on failure + */ +int __init aa_create_aafs(void) +{ + int error; + + if (!apparmor_initialized) + return 0; + + if (aa_fs_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); + if (error) + goto error; + + /* TODO: add support for apparmorfs_null and apparmorfs_mnt */ + + /* Report that AppArmor fs is enabled */ + aa_info_message("AppArmor Filesystem Enabled"); + return 0; + +error: + aa_destroy_aafs(); + AA_ERROR("Error creating AppArmor securityfs\n"); + return error; +} + +fs_initcall(aa_create_aafs); |