Exemplo n.º 1
0
/**
 * ima_load_data - appraise decision based on policy
 * @id: kernel load data caller identifier
 *
 * Callers of this LSM hook can not measure, appraise, or audit the
 * data provided by userspace.  Enforce policy rules requring a file
 * signature (eg. kexec'ed kernel image).
 *
 * For permission return 0, otherwise return -EACCES.
 */
int ima_load_data(enum kernel_load_data_id id)
{
	bool sig_enforce;

	if ((ima_appraise & IMA_APPRAISE_ENFORCE) != IMA_APPRAISE_ENFORCE)
		return 0;

	switch (id) {
	case LOADING_KEXEC_IMAGE:
		if (ima_appraise & IMA_APPRAISE_KEXEC) {
			pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
			return -EACCES;	/* INTEGRITY_UNKNOWN */
		}
		break;
	case LOADING_FIRMWARE:
		if (ima_appraise & IMA_APPRAISE_FIRMWARE) {
			pr_err("Prevent firmware sysfs fallback loading.\n");
			return -EACCES;	/* INTEGRITY_UNKNOWN */
		}
		break;
	case LOADING_MODULE:
		sig_enforce = is_module_sig_enforced();

		if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES)) {
			pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
			return -EACCES;	/* INTEGRITY_UNKNOWN */
		}
	default:
		break;
	}
	return 0;
}
Exemplo n.º 2
0
/**
 * ima_read_file - pre-measure/appraise hook decision based on policy
 * @file: pointer to the file to be measured/appraised/audit
 * @read_id: caller identifier
 *
 * Permit reading a file based on policy. The policy rules are written
 * in terms of the policy identifier.  Appraising the integrity of
 * a file requires a file descriptor.
 *
 * For permission return 0, otherwise return -EACCES.
 */
int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
{
	bool sig_enforce = is_module_sig_enforced();

	if (!file && read_id == READING_MODULE) {
		if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) &&
		    (ima_appraise & IMA_APPRAISE_ENFORCE)) {
			pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
			return -EACCES;	/* INTEGRITY_UNKNOWN */
		}
		return 0;	/* We rely on module signature checking */
	}
	return 0;
}