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