// SPDX-License-Identifier: GPL-2.0-only/* * Copyright (C) 2013 Politecnico di Torino, Italy *                    TORSEC group -- https://security.polito.it * * Author: Roberto Sassu <roberto.sassu@polito.it> * * File: ima_template.c *      Helpers to manage template descriptors. */ #include <linux/rculist.h>#include "ima.h"#include "ima_template_lib.h" enum header_fields { HDR_PCR, HDR_DIGEST, HDR_TEMPLATE_NAME,		     HDR_TEMPLATE_DATA, HDR__LAST }; static struct ima_template_desc builtin_templates[] = {	{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},	{.name = "ima-ng", .fmt = "d-ng|n-ng"},	{.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},	{.name = "ima-ngv2", .fmt = "d-ngv2|n-ng"},	{.name = "ima-sigv2", .fmt = "d-ngv2|n-ng|sig"},	{.name = "ima-buf", .fmt = "d-ng|n-ng|buf"},	{.name = "ima-modsig", .fmt = "d-ng|n-ng|sig|d-modsig|modsig"},	{.name = "evm-sig",	 .fmt = "d-ng|n-ng|evmsig|xattrnames|xattrlengths|xattrvalues|iuid|igid|imode"},	{.name = "", .fmt = ""},	/* placeholder for a custom format */}; static LIST_HEAD(defined_templates);static DEFINE_SPINLOCK(template_list);static int template_setup_done; static const struct ima_template_field supported_fields[] = {	{.field_id = "d", .field_init = ima_eventdigest_init,	 .field_show = ima_show_template_digest},	{.field_id = "n", .field_init = ima_eventname_init,	 .field_show = ima_show_template_string},	{.field_id = "d-ng", .field_init = ima_eventdigest_ng_init,	 .field_show = ima_show_template_digest_ng},	{.field_id = "d-ngv2", .field_init = ima_eventdigest_ngv2_init,	 .field_show = ima_show_template_digest_ngv2},	{.field_id = "n-ng", .field_init = ima_eventname_ng_init,	 .field_show = ima_show_template_string},	{.field_id = "sig", .field_init = ima_eventsig_init,	 .field_show = ima_show_template_sig},	{.field_id = "buf", .field_init = ima_eventbuf_init,	 .field_show = ima_show_template_buf},	{.field_id = "d-modsig", .field_init = ima_eventdigest_modsig_init,	 .field_show = ima_show_template_digest_ng},	{.field_id = "modsig", .field_init = ima_eventmodsig_init,	 .field_show = ima_show_template_sig},	{.field_id = "evmsig", .field_init = ima_eventevmsig_init,	 .field_show = ima_show_template_sig},	{.field_id = "iuid", .field_init = ima_eventinodeuid_init,	 .field_show = ima_show_template_uint},	{.field_id = "igid", .field_init = ima_eventinodegid_init,	 .field_show = ima_show_template_uint},	{.field_id = "imode", .field_init = ima_eventinodemode_init,	 .field_show = ima_show_template_uint},	{.field_id = "xattrnames",	 .field_init = ima_eventinodexattrnames_init,	 .field_show = ima_show_template_string},	{.field_id = "xattrlengths",	 .field_init = ima_eventinodexattrlengths_init,	 .field_show = ima_show_template_sig},	{.field_id = "xattrvalues",	 .field_init = ima_eventinodexattrvalues_init,	 .field_show = ima_show_template_sig},}; /* * Used when restoring measurements carried over from a kexec. 'd' and 'n' don't * need to be accounted for since they shouldn't be defined in the same template * description as 'd-ng' and 'n-ng' respectively. */#define MAX_TEMPLATE_NAME_LEN \	sizeof("d-ng|n-ng|evmsig|xattrnames|xattrlengths|xattrvalues|iuid|igid|imode") static struct ima_template_desc *ima_template;static struct ima_template_desc *ima_buf_template; /** * ima_template_has_modsig - Check whether template has modsig-related fields. * @ima_template: IMA template to check. * * Tells whether the given template has fields referencing a file's appended * signature. */bool ima_template_has_modsig(const struct ima_template_desc *ima_template){	int i; 	for (i = 0; i < ima_template->num_fields; i++)		if (!strcmp(ima_template->fields[i]->field_id, "modsig") ||		    !strcmp(ima_template->fields[i]->field_id, "d-modsig"))			return true; 	return false;} static int __init ima_template_setup(char *str){	struct ima_template_desc *template_desc;	int template_len = strlen(str); 	if (template_setup_done)		return 1; 	if (!ima_template)		ima_init_template_list(); 	/*	 * Verify that a template with the supplied name exists.	 * If not, use CONFIG_IMA_DEFAULT_TEMPLATE.	 */	template_desc = lookup_template_desc(str);	if (!template_desc) {		pr_err("template %s not found, using %s\n",		       str, CONFIG_IMA_DEFAULT_TEMPLATE);		return 1;	} 	/*	 * Verify whether the current hash algorithm is supported	 * by the 'ima' template.	 */	if (template_len == 3 && strcmp(str, IMA_TEMPLATE_IMA_NAME) == 0 &&	    ima_hash_algo != HASH_ALGO_SHA1 && ima_hash_algo != HASH_ALGO_MD5) {		pr_err("template does not support hash alg\n");		return 1;	} 	ima_template = template_desc;	template_setup_done = 1;	return 1;}__setup("ima_template=", ima_template_setup); static int __init ima_template_fmt_setup(char *str){	int num_templates = ARRAY_SIZE(builtin_templates); 	if (template_setup_done)		return 1; 	if (template_desc_init_fields(str, NULL, NULL) < 0) {		pr_err("format string '%s' not valid, using template %s\n",		       str, CONFIG_IMA_DEFAULT_TEMPLATE);		return 1;	} 	builtin_templates[num_templates - 1].fmt = str;	ima_template = builtin_templates + num_templates - 1;	template_setup_done = 1; 	return 1;}__setup("ima_template_fmt=", ima_template_fmt_setup); struct ima_template_desc *lookup_template_desc(const char *name){	struct ima_template_desc *template_desc;	int found = 0; 	rcu_read_lock();	list_for_each_entry_rcu(template_desc, &defined_templates, list) {		if ((strcmp(template_desc->name, name) == 0) ||		    (strcmp(template_desc->fmt, name) == 0)) {			found = 1;			break;		}	}	rcu_read_unlock();	return found ? template_desc : NULL;} static const struct ima_template_field *lookup_template_field(const char *field_id){	int i; 	for (i = 0; i < ARRAY_SIZE(supported_fields); i++)		if (strncmp(supported_fields[i].field_id, field_id,			    IMA_TEMPLATE_FIELD_ID_MAX_LEN) == 0)			return &supported_fields[i];	return NULL;} static int template_fmt_size(const char *template_fmt){	char c;	int template_fmt_len = strlen(template_fmt);	int i = 0, j = 0; 	while (i < template_fmt_len) {		c = template_fmt[i];		if (c == '|')			j++;		i++;	} 	return j + 1;} int template_desc_init_fields(const char *template_fmt,			      const struct ima_template_field ***fields,			      int *num_fields){	const char *template_fmt_ptr;	const struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];	int template_num_fields;	int i, len; 	if (num_fields && *num_fields > 0) /* already initialized? */		return 0; 	template_num_fields = template_fmt_size(template_fmt); 	if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {		pr_err("format string '%s' contains too many fields\n",		       template_fmt);		return -EINVAL;	} 	for (i = 0, template_fmt_ptr = template_fmt; i < template_num_fields;	     i++, template_fmt_ptr += len + 1) {		char tmp_field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN + 1]; 		len = strchrnul(template_fmt_ptr, '|') - template_fmt_ptr;		if (len == 0 || len > IMA_TEMPLATE_FIELD_ID_MAX_LEN) {			pr_err("Invalid field with length %d\n", len);			return -EINVAL;		} 		memcpy(tmp_field_id, template_fmt_ptr, len);		tmp_field_id[len] = '\0';		found_fields[i] = lookup_template_field(tmp_field_id);		if (!found_fields[i]) {			pr_err("field '%s' not found\n", tmp_field_id);			return -ENOENT;		}	} 	if (fields && num_fields) {		*fields = kmalloc_objs(**fields, i);		if (*fields == NULL)			return -ENOMEM; 		memcpy(*fields, found_fields, i * sizeof(**fields));		*num_fields = i;	} 	return 0;} void ima_init_template_list(void){	int i; 	if (!list_empty(&defined_templates))		return; 	spin_lock(&template_list);	for (i = 0; i < ARRAY_SIZE(builtin_templates); i++) {		list_add_tail_rcu(&builtin_templates[i].list,				  &defined_templates);	}	spin_unlock(&template_list);} struct ima_template_desc *ima_template_desc_current(void){	if (!ima_template) {		ima_init_template_list();		ima_template =		    lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE);	}	return ima_template;} struct ima_template_desc *ima_template_desc_buf(void){	if (!ima_buf_template) {		ima_init_template_list();		ima_buf_template = lookup_template_desc("ima-buf");	}	return ima_buf_template;} int __init ima_init_template(void){	struct ima_template_desc *template = ima_template_desc_current();	int result; 	result = template_desc_init_fields(template->fmt,					   &(template->fields),					   &(template->num_fields));	if (result < 0) {		pr_err("template %s init failed, result: %d\n",		       (strlen(template->name) ?		       template->name : template->fmt), result);		return result;	} 	template = ima_template_desc_buf();	if (!template) {		pr_err("Failed to get ima-buf template\n");		return -EINVAL;	} 	result = template_desc_init_fields(template->fmt,					   &(template->fields),					   &(template->num_fields));	if (result < 0)		pr_err("template %s init failed, result: %d\n",		       (strlen(template->name) ?		       template->name : template->fmt), result); 	return result;} static struct ima_template_desc *restore_template_fmt(char *template_name){	struct ima_template_desc *template_desc = NULL;	int ret; 	ret = template_desc_init_fields(template_name, NULL, NULL);	if (ret < 0) {		pr_err("attempting to initialize the template \"%s\" failed\n",			template_name);		goto out;	} 	template_desc = kzalloc_obj(*template_desc);	if (!template_desc)		goto out; 	template_desc->name = "";	template_desc->fmt = kstrdup(template_name, GFP_KERNEL);	if (!template_desc->fmt) {		kfree(template_desc);		template_desc = NULL;		goto out;	} 	spin_lock(&template_list);	list_add_tail_rcu(&template_desc->list, &defined_templates);	spin_unlock(&template_list);out:	return template_desc;} static int ima_restore_template_data(struct ima_template_desc *template_desc,				     void *template_data,				     int template_data_size,				     struct ima_template_entry **entry){	struct tpm_digest *digests;	int ret = 0;	int i; 	*entry = kzalloc_flex(**entry, template_data, template_desc->num_fields,			      GFP_NOFS);	if (!*entry)		return -ENOMEM; 	digests = kzalloc_objs(*digests,			       NR_BANKS(ima_tpm_chip) + ima_extra_slots,			       GFP_NOFS);	if (!digests) {		kfree(*entry);		return -ENOMEM;	} 	(*entry)->digests = digests; 	ret = ima_parse_buf(template_data, template_data + template_data_size,			    NULL, template_desc->num_fields,			    (*entry)->template_data, NULL, NULL,			    ENFORCE_FIELDS | ENFORCE_BUFEND, "template data");	if (ret < 0) {		kfree((*entry)->digests);		kfree(*entry);		return ret;	} 	(*entry)->template_desc = template_desc;	for (i = 0; i < template_desc->num_fields; i++) {		struct ima_field_data *field_data = &(*entry)->template_data[i];		u8 *data = field_data->data; 		(*entry)->template_data[i].data =			kzalloc(field_data->len + 1, GFP_KERNEL);		if (!(*entry)->template_data[i].data) {			ret = -ENOMEM;			break;		}		memcpy((*entry)->template_data[i].data, data, field_data->len);		(*entry)->template_data_len += sizeof(field_data->len);		(*entry)->template_data_len += field_data->len;	} 	if (ret < 0) {		ima_free_template_entry(*entry);		*entry = NULL;	} 	return ret;} /* Restore the serialized binary measurement list without extending PCRs. */int ima_restore_measurement_list(loff_t size, void *buf){	char template_name[MAX_TEMPLATE_NAME_LEN];	unsigned char zero[TPM_DIGEST_SIZE] = { 0 }; 	struct ima_kexec_hdr *khdr = buf;	struct ima_field_data hdr[HDR__LAST] = {		[HDR_PCR] = {.len = sizeof(u32)},		[HDR_DIGEST] = {.len = TPM_DIGEST_SIZE},	}; 	void *bufp = buf + sizeof(*khdr);	void *bufendp;	struct ima_template_entry *entry;	struct ima_template_desc *template_desc;	DECLARE_BITMAP(hdr_mask, HDR__LAST);	unsigned long count = 0;	int ret = 0; 	if (!buf || size < sizeof(*khdr))		return 0; 	if (ima_canonical_fmt) {		khdr->version = le16_to_cpu((__force __le16)khdr->version);		khdr->count = le64_to_cpu((__force __le64)khdr->count);		khdr->buffer_size = le64_to_cpu((__force __le64)khdr->buffer_size);	} 	if (khdr->version != 1) {		pr_err("attempting to restore a incompatible measurement list");		return -EINVAL;	} 	if (khdr->count > ULONG_MAX - 1) {		pr_err("attempting to restore too many measurements");		return -EINVAL;	} 	bitmap_zero(hdr_mask, HDR__LAST);	bitmap_set(hdr_mask, HDR_PCR, 1);	bitmap_set(hdr_mask, HDR_DIGEST, 1); 	/*	 * ima kexec buffer prefix: version, buffer size, count	 * v1 format: pcr, digest, template-name-len, template-name,	 *	      template-data-size, template-data	 */	bufendp = buf + khdr->buffer_size;	while ((bufp < bufendp) && (count++ < khdr->count)) {		int enforce_mask = ENFORCE_FIELDS; 		enforce_mask |= (count == khdr->count) ? ENFORCE_BUFEND : 0;		ret = ima_parse_buf(bufp, bufendp, &bufp, HDR__LAST, hdr, NULL,				    hdr_mask, enforce_mask, "entry header");		if (ret < 0)			break; 		if (hdr[HDR_TEMPLATE_NAME].len >= MAX_TEMPLATE_NAME_LEN) {			pr_err("attempting to restore a template name that is too long\n");			ret = -EINVAL;			break;		} 		/* template name is not null terminated */		memcpy(template_name, hdr[HDR_TEMPLATE_NAME].data,		       hdr[HDR_TEMPLATE_NAME].len);		template_name[hdr[HDR_TEMPLATE_NAME].len] = 0; 		if (strcmp(template_name, "ima") == 0) {			pr_err("attempting to restore an unsupported template \"%s\" failed\n",			       template_name);			ret = -EINVAL;			break;		} 		template_desc = lookup_template_desc(template_name);		if (!template_desc) {			template_desc = restore_template_fmt(template_name);			if (!template_desc)				break;		} 		/*		 * Only the running system's template format is initialized		 * on boot.  As needed, initialize the other template formats.		 */

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