![Kees Cook](/assets/img/avatar_default.png)
Since the parser needs to know which rlimits are known to the kernel, export the list via a mask file in the "rlimit" subdirectory in the securityfs "features" directory. Signed-off-by: Kees Cook <kees@ubuntu.com> Signed-off-by: John Johansen <john.johansen@canonical.com>
356 lines
8.4 KiB
C
356 lines
8.4 KiB
C
/*
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* AppArmor security module
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*
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* This file contains AppArmor /sys/kernel/security/apparmor interface functions
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*
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* Copyright (C) 1998-2008 Novell/SUSE
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* Copyright 2009-2010 Canonical Ltd.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*/
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#include <linux/security.h>
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#include <linux/vmalloc.h>
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#include <linux/module.h>
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#include <linux/seq_file.h>
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#include <linux/uaccess.h>
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#include <linux/namei.h>
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#include <linux/capability.h>
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#include "include/apparmor.h"
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#include "include/apparmorfs.h"
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#include "include/audit.h"
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#include "include/context.h"
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#include "include/policy.h"
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#include "include/resource.h"
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/**
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* aa_simple_write_to_buffer - common routine for getting policy from user
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* @op: operation doing the user buffer copy
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* @userbuf: user buffer to copy data from (NOT NULL)
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* @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size)
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* @copy_size: size of data to copy from user buffer
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* @pos: position write is at in the file (NOT NULL)
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*
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* Returns: kernel buffer containing copy of user buffer data or an
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* ERR_PTR on failure.
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*/
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static char *aa_simple_write_to_buffer(int op, const char __user *userbuf,
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size_t alloc_size, size_t copy_size,
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loff_t *pos)
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{
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char *data;
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BUG_ON(copy_size > alloc_size);
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if (*pos != 0)
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/* only writes from pos 0, that is complete writes */
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return ERR_PTR(-ESPIPE);
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/*
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* Don't allow profile load/replace/remove from profiles that don't
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* have CAP_MAC_ADMIN
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*/
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if (!aa_may_manage_policy(op))
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return ERR_PTR(-EACCES);
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/* freed by caller to simple_write_to_buffer */
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data = kvmalloc(alloc_size);
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if (data == NULL)
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return ERR_PTR(-ENOMEM);
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if (copy_from_user(data, userbuf, copy_size)) {
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kvfree(data);
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return ERR_PTR(-EFAULT);
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}
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return data;
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}
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/* .load file hook fn to load policy */
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static ssize_t profile_load(struct file *f, const char __user *buf, size_t size,
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loff_t *pos)
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{
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char *data;
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ssize_t error;
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data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos);
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error = PTR_ERR(data);
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if (!IS_ERR(data)) {
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error = aa_replace_profiles(data, size, PROF_ADD);
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kvfree(data);
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}
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return error;
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}
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static const struct file_operations aa_fs_profile_load = {
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.write = profile_load,
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.llseek = default_llseek,
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};
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/* .replace file hook fn to load and/or replace policy */
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static ssize_t profile_replace(struct file *f, const char __user *buf,
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size_t size, loff_t *pos)
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{
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char *data;
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ssize_t error;
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data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos);
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error = PTR_ERR(data);
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if (!IS_ERR(data)) {
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error = aa_replace_profiles(data, size, PROF_REPLACE);
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kvfree(data);
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}
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return error;
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}
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static const struct file_operations aa_fs_profile_replace = {
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.write = profile_replace,
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.llseek = default_llseek,
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};
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/* .remove file hook fn to remove loaded policy */
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static ssize_t profile_remove(struct file *f, const char __user *buf,
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size_t size, loff_t *pos)
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{
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char *data;
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ssize_t error;
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/*
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* aa_remove_profile needs a null terminated string so 1 extra
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* byte is allocated and the copied data is null terminated.
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*/
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data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos);
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error = PTR_ERR(data);
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if (!IS_ERR(data)) {
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data[size] = 0;
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error = aa_remove_profiles(data, size);
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kvfree(data);
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}
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return error;
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}
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static const struct file_operations aa_fs_profile_remove = {
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.write = profile_remove,
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.llseek = default_llseek,
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};
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static int aa_fs_seq_show(struct seq_file *seq, void *v)
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{
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struct aa_fs_entry *fs_file = seq->private;
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if (!fs_file)
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return 0;
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switch (fs_file->v_type) {
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case AA_FS_TYPE_BOOLEAN:
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seq_printf(seq, "%s\n", fs_file->v.boolean ? "yes" : "no");
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break;
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case AA_FS_TYPE_STRING:
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seq_printf(seq, "%s\n", fs_file->v.string);
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break;
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case AA_FS_TYPE_U64:
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seq_printf(seq, "%#08lx\n", fs_file->v.u64);
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break;
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default:
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/* Ignore unpritable entry types. */
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break;
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}
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return 0;
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}
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static int aa_fs_seq_open(struct inode *inode, struct file *file)
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{
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return single_open(file, aa_fs_seq_show, inode->i_private);
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}
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const struct file_operations aa_fs_seq_file_ops = {
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.owner = THIS_MODULE,
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.open = aa_fs_seq_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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/** Base file system setup **/
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static struct aa_fs_entry aa_fs_entry_file[] = {
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AA_FS_FILE_STRING("mask", "create read write exec append mmap_exec " \
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"link lock"),
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{ }
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};
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static struct aa_fs_entry aa_fs_entry_domain[] = {
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AA_FS_FILE_BOOLEAN("change_hat", 1),
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AA_FS_FILE_BOOLEAN("change_hatv", 1),
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AA_FS_FILE_BOOLEAN("change_onexec", 1),
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AA_FS_FILE_BOOLEAN("change_profile", 1),
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{ }
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};
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static struct aa_fs_entry aa_fs_entry_features[] = {
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AA_FS_DIR("domain", aa_fs_entry_domain),
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AA_FS_DIR("file", aa_fs_entry_file),
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AA_FS_FILE_U64("capability", VFS_CAP_FLAGS_MASK),
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AA_FS_DIR("rlimit", aa_fs_entry_rlimit),
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{ }
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};
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static struct aa_fs_entry aa_fs_entry_apparmor[] = {
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AA_FS_FILE_FOPS(".load", 0640, &aa_fs_profile_load),
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AA_FS_FILE_FOPS(".replace", 0640, &aa_fs_profile_replace),
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AA_FS_FILE_FOPS(".remove", 0640, &aa_fs_profile_remove),
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AA_FS_DIR("features", aa_fs_entry_features),
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{ }
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};
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static struct aa_fs_entry aa_fs_entry =
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AA_FS_DIR("apparmor", aa_fs_entry_apparmor);
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/**
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* aafs_create_file - create a file entry in the apparmor securityfs
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* @fs_file: aa_fs_entry to build an entry for (NOT NULL)
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* @parent: the parent dentry in the securityfs
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*
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* Use aafs_remove_file to remove entries created with this fn.
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*/
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static int __init aafs_create_file(struct aa_fs_entry *fs_file,
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struct dentry *parent)
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{
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int error = 0;
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fs_file->dentry = securityfs_create_file(fs_file->name,
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S_IFREG | fs_file->mode,
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parent, fs_file,
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fs_file->file_ops);
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if (IS_ERR(fs_file->dentry)) {
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error = PTR_ERR(fs_file->dentry);
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fs_file->dentry = NULL;
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}
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return error;
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}
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/**
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* aafs_create_dir - recursively create a directory entry in the securityfs
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* @fs_dir: aa_fs_entry (and all child entries) to build (NOT NULL)
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* @parent: the parent dentry in the securityfs
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*
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* Use aafs_remove_dir to remove entries created with this fn.
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*/
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static int __init aafs_create_dir(struct aa_fs_entry *fs_dir,
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struct dentry *parent)
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{
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int error;
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struct aa_fs_entry *fs_file;
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fs_dir->dentry = securityfs_create_dir(fs_dir->name, parent);
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if (IS_ERR(fs_dir->dentry)) {
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error = PTR_ERR(fs_dir->dentry);
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fs_dir->dentry = NULL;
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goto failed;
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}
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for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) {
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if (fs_file->v_type == AA_FS_TYPE_DIR)
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error = aafs_create_dir(fs_file, fs_dir->dentry);
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else
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error = aafs_create_file(fs_file, fs_dir->dentry);
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if (error)
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goto failed;
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}
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return 0;
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failed:
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return error;
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}
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/**
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* aafs_remove_file - drop a single file entry in the apparmor securityfs
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* @fs_file: aa_fs_entry to detach from the securityfs (NOT NULL)
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*/
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static void __init aafs_remove_file(struct aa_fs_entry *fs_file)
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{
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if (!fs_file->dentry)
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return;
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securityfs_remove(fs_file->dentry);
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fs_file->dentry = NULL;
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}
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/**
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* aafs_remove_dir - recursively drop a directory entry from the securityfs
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* @fs_dir: aa_fs_entry (and all child entries) to detach (NOT NULL)
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*/
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static void __init aafs_remove_dir(struct aa_fs_entry *fs_dir)
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{
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struct aa_fs_entry *fs_file;
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for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) {
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if (fs_file->v_type == AA_FS_TYPE_DIR)
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aafs_remove_dir(fs_file);
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else
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aafs_remove_file(fs_file);
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}
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aafs_remove_file(fs_dir);
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}
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/**
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* aa_destroy_aafs - cleanup and free aafs
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*
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* releases dentries allocated by aa_create_aafs
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*/
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void __init aa_destroy_aafs(void)
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{
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aafs_remove_dir(&aa_fs_entry);
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}
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/**
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* aa_create_aafs - create the apparmor security filesystem
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*
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* dentries created here are released by aa_destroy_aafs
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*
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* Returns: error on failure
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*/
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static int __init aa_create_aafs(void)
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{
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int error;
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if (!apparmor_initialized)
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return 0;
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if (aa_fs_entry.dentry) {
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AA_ERROR("%s: AppArmor securityfs already exists\n", __func__);
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return -EEXIST;
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}
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/* Populate fs tree. */
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error = aafs_create_dir(&aa_fs_entry, NULL);
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if (error)
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goto error;
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/* TODO: add support for apparmorfs_null and apparmorfs_mnt */
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/* Report that AppArmor fs is enabled */
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aa_info_message("AppArmor Filesystem Enabled");
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return 0;
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error:
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aa_destroy_aafs();
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AA_ERROR("Error creating AppArmor securityfs\n");
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return error;
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}
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fs_initcall(aa_create_aafs);
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