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288 lines
6.4 KiB
288 lines
6.4 KiB
/*
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* Copyright (C) 2008 IBM Corporation
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*
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* Authors:
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* Mimi Zohar <zohar@us.ibm.com>
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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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* File: integrity_iint.c
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* - implements the integrity hooks: integrity_inode_alloc,
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* integrity_inode_free
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* - cache integrity information associated with an inode
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* using a rbtree tree.
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*/
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/rbtree.h>
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#include <linux/file.h>
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#include <linux/uaccess.h>
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#ifdef CONFIG_FIVE
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#include <uapi/linux/magic.h>
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#endif
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#include "integrity.h"
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static struct rb_root integrity_iint_tree = RB_ROOT;
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static DEFINE_RWLOCK(integrity_iint_lock);
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static struct kmem_cache *iint_cache __read_mostly;
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/*
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* __integrity_iint_find - return the iint associated with an inode
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*/
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static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode)
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{
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struct integrity_iint_cache *iint;
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struct rb_node *n = integrity_iint_tree.rb_node;
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while (n) {
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iint = rb_entry(n, struct integrity_iint_cache, rb_node);
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if (inode < iint->inode)
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n = n->rb_left;
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else if (inode > iint->inode)
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n = n->rb_right;
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else
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break;
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}
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if (!n)
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return NULL;
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return iint;
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}
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/*
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* integrity_iint_find - return the iint associated with an inode
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*/
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struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
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{
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struct integrity_iint_cache *iint;
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if (!IS_IMA(inode))
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return NULL;
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read_lock(&integrity_iint_lock);
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iint = __integrity_iint_find(inode);
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read_unlock(&integrity_iint_lock);
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return iint;
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}
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static void iint_free(struct integrity_iint_cache *iint)
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{
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#ifdef CONFIG_FIVE
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kfree(iint->five_label);
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iint->five_label = NULL;
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iint->five_flags = 0UL;
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iint->five_status = FIVE_FILE_UNKNOWN;
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iint->five_signing = false;
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#endif
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kfree(iint->ima_hash);
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iint->ima_hash = NULL;
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iint->version = 0;
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iint->flags = 0UL;
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iint->atomic_flags = 0UL;
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iint->ima_file_status = INTEGRITY_UNKNOWN;
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iint->ima_mmap_status = INTEGRITY_UNKNOWN;
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iint->ima_bprm_status = INTEGRITY_UNKNOWN;
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iint->ima_read_status = INTEGRITY_UNKNOWN;
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iint->evm_status = INTEGRITY_UNKNOWN;
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iint->measured_pcrs = 0;
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kmem_cache_free(iint_cache, iint);
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}
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/**
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* integrity_inode_get - find or allocate an iint associated with an inode
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* @inode: pointer to the inode
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* @return: allocated iint
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*
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* Caller must lock i_mutex
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*/
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struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
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{
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struct rb_node **p;
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struct rb_node *node, *parent = NULL;
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struct integrity_iint_cache *iint, *test_iint;
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iint = integrity_iint_find(inode);
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if (iint)
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return iint;
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iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
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if (!iint)
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return NULL;
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write_lock(&integrity_iint_lock);
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p = &integrity_iint_tree.rb_node;
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while (*p) {
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parent = *p;
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test_iint = rb_entry(parent, struct integrity_iint_cache,
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rb_node);
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if (inode < test_iint->inode)
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p = &(*p)->rb_left;
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else
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p = &(*p)->rb_right;
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}
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iint->inode = inode;
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node = &iint->rb_node;
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inode->i_flags |= S_IMA;
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rb_link_node(node, parent, p);
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rb_insert_color(node, &integrity_iint_tree);
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write_unlock(&integrity_iint_lock);
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return iint;
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}
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/**
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* integrity_inode_free - called on security_inode_free
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* @inode: pointer to the inode
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*
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* Free the integrity information(iint) associated with an inode.
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*/
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void integrity_inode_free(struct inode *inode)
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{
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struct integrity_iint_cache *iint;
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if (!IS_IMA(inode))
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return;
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write_lock(&integrity_iint_lock);
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iint = __integrity_iint_find(inode);
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rb_erase(&iint->rb_node, &integrity_iint_tree);
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write_unlock(&integrity_iint_lock);
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iint_free(iint);
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}
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static void init_once(void *foo)
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{
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struct integrity_iint_cache *iint = foo;
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memset(iint, 0, sizeof(*iint));
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iint->version = 0;
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#ifdef CONFIG_FIVE
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iint->five_flags = 0UL;
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iint->five_status = FIVE_FILE_UNKNOWN;
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iint->five_signing = false;
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#endif
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iint->flags = 0UL;
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iint->atomic_flags = 0;
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iint->ima_file_status = INTEGRITY_UNKNOWN;
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iint->ima_mmap_status = INTEGRITY_UNKNOWN;
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iint->ima_bprm_status = INTEGRITY_UNKNOWN;
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iint->ima_read_status = INTEGRITY_UNKNOWN;
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iint->evm_status = INTEGRITY_UNKNOWN;
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iint->measured_pcrs = 0;
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mutex_init(&iint->mutex);
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}
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static int __init integrity_iintcache_init(void)
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{
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iint_cache =
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kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
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0, SLAB_PANIC, init_once);
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return 0;
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}
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security_initcall(integrity_iintcache_init);
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/*
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* integrity_kernel_read - read data from the file
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*
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* This is a function for reading file content instead of kernel_read().
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* It does not perform locking checks to ensure it cannot be blocked.
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* It does not perform security checks because it is irrelevant for IMA.
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*
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*/
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int integrity_kernel_read(struct file *file, loff_t offset,
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void *addr, unsigned long count)
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{
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mm_segment_t old_fs;
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char __user *buf = (char __user *)addr;
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ssize_t ret;
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#ifdef CONFIG_FIVE
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struct inode *inode = file_inode(file);
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#endif
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if (!(file->f_mode & FMODE_READ))
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return -EBADF;
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old_fs = get_fs();
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set_fs(get_ds());
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#ifdef CONFIG_FIVE
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if (inode->i_sb->s_magic == OVERLAYFS_SUPER_MAGIC && file->private_data)
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file = (struct file *)file->private_data;
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#endif
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ret = __vfs_read(file, buf, count, &offset);
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set_fs(old_fs);
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return ret;
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}
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/*
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* integrity_read_file - read entire file content into the buffer
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*
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* This is function opens a file, allocates the buffer of required
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* size, read entire file content to the buffer and closes the file
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*
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* It is used only by init code.
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*
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*/
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int __init integrity_read_file(const char *path, char **data)
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{
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struct file *file;
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loff_t size;
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char *buf;
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int rc = -EINVAL;
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if (!path || !*path)
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return -EINVAL;
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file = filp_open(path, O_RDONLY, 0);
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if (IS_ERR(file)) {
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rc = PTR_ERR(file);
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pr_err("Unable to open file: %s (%d)", path, rc);
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return rc;
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}
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size = i_size_read(file_inode(file));
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if (size <= 0)
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goto out;
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buf = kmalloc(size, GFP_KERNEL);
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if (!buf) {
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rc = -ENOMEM;
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goto out;
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}
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rc = integrity_kernel_read(file, 0, buf, size);
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if (rc == size) {
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*data = buf;
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} else {
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kfree(buf);
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if (rc >= 0)
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rc = -EIO;
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}
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out:
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fput(file);
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return rc;
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}
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/*
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* integrity_load_keys - load integrity keys hook
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*
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* Hooks is called from init/main.c:kernel_init_freeable()
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* when rootfs is ready
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*/
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void __init integrity_load_keys(void)
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{
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ima_load_x509();
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evm_load_x509();
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}
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