Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 439 insertions, 0 deletions

diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
new file mode 100644
index 000000000..4dfdccce4
--- /dev/null
+++ b/security/integrity/ima/ima_template.c
@@ -0,0 +1,439 @@
+/*
+ * Copyright (C) 2013 Politecnico di Torino, Italy
+ *                    TORSEC group -- http://security.polito.it
+ *
+ * Author: Roberto Sassu <roberto.sassu@polito.it>
+ *
+ * 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: ima_template.c
+ *      Helpers to manage template descriptors.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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 = "", .fmt = ""},	/* placeholder for a custom format */
+};
+
+static LIST_HEAD(defined_templates);
+static DEFINE_SPINLOCK(template_list);
+static int template_setup_done;
+
+static 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 = "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},
+};
+#define MAX_TEMPLATE_NAME_LEN 15
+
+static struct ima_template_desc *ima_template;
+static struct ima_template_desc *lookup_template_desc(const char *name);
+static int template_desc_init_fields(const char *template_fmt,
+				     struct ima_template_field ***fields,
+				     int *num_fields);
+
+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);
+
+static 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 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;
+}
+
+static int template_desc_init_fields(const char *template_fmt,
+				     struct ima_template_field ***fields,
+				     int *num_fields)
+{
+	const char *template_fmt_ptr;
+	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_array(i, sizeof(*fields), GFP_KERNEL);
+		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;
+}
+
+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;
+}
+
+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(sizeof(*template_desc), GFP_KERNEL);
+	if (!template_desc)
+		goto out;
+
+	template_desc->name = "";
+	template_desc->fmt = kstrdup(template_name, GFP_KERNEL);
+	if (!template_desc->fmt)
+		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)
+{
+	int ret = 0;
+	int i;
+
+	*entry = kzalloc(sizeof(**entry) +
+		    template_desc->num_fields * sizeof(struct ima_field_data),
+		    GFP_NOFS);
+	if (!*entry)
+		return -ENOMEM;
+
+	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);
+		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];
+
+	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(khdr->version);
+		khdr->count = le64_to_cpu(khdr->count);
+		khdr->buffer_size = le64_to_cpu(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.
+		 */
+		ret = template_desc_init_fields(template_desc->fmt,
+						&(template_desc->fields),
+						&(template_desc->num_fields));
+		if (ret < 0) {
+			pr_err("attempting to restore the template fmt \"%s\" failed\n",
+			       template_desc->fmt);
+			ret = -EINVAL;
+			break;
+		}
+
+		ret = ima_restore_template_data(template_desc,
+						hdr[HDR_TEMPLATE_DATA].data,
+						hdr[HDR_TEMPLATE_DATA].len,
+						&entry);
+		if (ret < 0)
+			break;
+
+		memcpy(entry->digest, hdr[HDR_DIGEST].data,
+		       hdr[HDR_DIGEST].len);
+		entry->pcr = !ima_canonical_fmt ? *(hdr[HDR_PCR].data) :
+			     le32_to_cpu(*(hdr[HDR_PCR].data));
+		ret = ima_restore_measurement_entry(entry);
+		if (ret < 0)
+			break;
+
+	}
+	return ret;
+}