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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /security/integrity/ima/ima_template.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'security/integrity/ima/ima_template.c')
-rw-r--r--security/integrity/ima/ima_template.c536
1 files changed, 536 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..04c49f05c
--- /dev/null
+++ b/security/integrity/ima/ima_template.c
@@ -0,0 +1,536 @@
+// 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_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;
+}
+
+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(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) {
+ 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(struct_size(*entry, template_data,
+ template_desc->num_fields), GFP_NOFS);
+ if (!*entry)
+ return -ENOMEM;
+
+ digests = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots,
+ sizeof(*digests), 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.
+ */
+ 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;
+
+ if (memcmp(hdr[HDR_DIGEST].data, zero, sizeof(zero))) {
+ ret = ima_calc_field_array_hash(
+ &entry->template_data[0],
+ entry);
+ if (ret < 0) {
+ pr_err("cannot calculate template digest\n");
+ ret = -EINVAL;
+ break;
+ }
+ }
+
+ entry->pcr = !ima_canonical_fmt ? *(u32 *)(hdr[HDR_PCR].data) :
+ le32_to_cpu(*(__le32 *)(hdr[HDR_PCR].data));
+ ret = ima_restore_measurement_entry(entry);
+ if (ret < 0)
+ break;
+
+ }
+ return ret;
+}