| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2008 IBM Corporation |
| * |
| * Authors: |
| * Mimi Zohar <zohar@us.ibm.com> |
| * |
| * 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/init.h> |
| #include <linux/spinlock.h> |
| #include <linux/rbtree.h> |
| #include <linux/file.h> |
| #include <linux/uaccess.h> |
| #include <linux/security.h> |
| #include <linux/lsm_hooks.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; |
| |
| struct dentry *integrity_dir; |
| |
| /* |
| * __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->ima_creds_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; |
| |
| /* |
| * The integrity's "iint_cache" is initialized at security_init(), |
| * unless it is not included in the ordered list of LSMs enabled |
| * on the boot command line. |
| */ |
| if (!iint_cache) |
| panic("%s: lsm=integrity required.\n", __func__); |
| |
| 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 = (struct integrity_iint_cache *) foo; |
| |
| memset(iint, 0, sizeof(*iint)); |
| 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->ima_creds_status = INTEGRITY_UNKNOWN; |
| iint->evm_status = INTEGRITY_UNKNOWN; |
| 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; |
| } |
| DEFINE_LSM(integrity) = { |
| .name = "integrity", |
| .init = 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, |
| void *addr, unsigned long count) |
| { |
| return __kernel_read(file, addr, count, &offset); |
| } |
| |
| /* |
| * 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(); |
| } |
| |
| static int __init integrity_fs_init(void) |
| { |
| integrity_dir = securityfs_create_dir("integrity", NULL); |
| if (IS_ERR(integrity_dir)) { |
| int ret = PTR_ERR(integrity_dir); |
| |
| if (ret != -ENODEV) |
| pr_err("Unable to create integrity sysfs dir: %d\n", |
| ret); |
| integrity_dir = NULL; |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| late_initcall(integrity_fs_init) |