ipe.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved.
 */
#include <uapi/linux/lsm.h>

#include "ipe.h"
#include "eval.h"
#include "hooks.h"

extern const char *const ipe_boot_policy;
bool ipe_enabled;

static struct lsm_blob_sizes ipe_blobs __ro_after_init = {
	.lbs_superblock = sizeof(struct ipe_superblock),
#ifdef CONFIG_IPE_PROP_DM_VERITY
	.lbs_bdev = sizeof(struct ipe_bdev),
#endif /* CONFIG_IPE_PROP_DM_VERITY */
#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG
	.lbs_inode = sizeof(struct ipe_inode),
#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */
};

static const struct lsm_id ipe_lsmid = {
	.name = "ipe",
	.id = LSM_ID_IPE,
};

struct ipe_superblock *ipe_sb(const struct super_block *sb)
{
	return sb->s_security + ipe_blobs.lbs_superblock;
}

#ifdef CONFIG_IPE_PROP_DM_VERITY
struct ipe_bdev *ipe_bdev(struct block_device *b)
{
	return b->bd_security + ipe_blobs.lbs_bdev;
}
#endif /* CONFIG_IPE_PROP_DM_VERITY */

#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG
struct ipe_inode *ipe_inode(const struct inode *inode)
{
	return inode->i_security + ipe_blobs.lbs_inode;
}
#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */

static struct security_hook_list ipe_hooks[] __ro_after_init = {
	LSM_HOOK_INIT(bprm_check_security, ipe_bprm_check_security),
	LSM_HOOK_INIT(mmap_file, ipe_mmap_file),
	LSM_HOOK_INIT(file_mprotect, ipe_file_mprotect),
	LSM_HOOK_INIT(kernel_read_file, ipe_kernel_read_file),
	LSM_HOOK_INIT(kernel_load_data, ipe_kernel_load_data),
	LSM_HOOK_INIT(initramfs_populated, ipe_unpack_initramfs),
#ifdef CONFIG_IPE_PROP_DM_VERITY
	LSM_HOOK_INIT(bdev_free_security, ipe_bdev_free_security),
	LSM_HOOK_INIT(bdev_setintegrity, ipe_bdev_setintegrity),
#endif /* CONFIG_IPE_PROP_DM_VERITY */
#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG
	LSM_HOOK_INIT(inode_setintegrity, ipe_inode_setintegrity),
#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */
};

/**
 * ipe_init() - Entry point of IPE.
 *
 * This is called at LSM init, which happens occurs early during kernel
 * start up. During this phase, IPE registers its hooks and loads the
 * builtin boot policy.
 *
 * Return:
 * * %0		- OK
 * * %-ENOMEM	- Out of memory (OOM)
 */
static int __init ipe_init(void)
{
	struct ipe_policy *p = NULL;

	security_add_hooks(ipe_hooks, ARRAY_SIZE(ipe_hooks), &ipe_lsmid);
	ipe_enabled = true;

	if (ipe_boot_policy) {
		p = ipe_new_policy(ipe_boot_policy, strlen(ipe_boot_policy),
				   NULL, 0);
		if (IS_ERR(p))
			return PTR_ERR(p);

		rcu_assign_pointer(ipe_active_policy, p);
	}

	return 0;
}

DEFINE_LSM(ipe) = {
	.name = "ipe",
	.init = ipe_init,
	.blobs = &ipe_blobs,
};