diff options
Diffstat (limited to 'security/integrity/ima/ima_template.c')
| -rw-r--r-- | security/integrity/ima/ima_template.c | 297 |
1 files changed, 284 insertions, 13 deletions
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index febd12ed9b55..cebb37c63629 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -15,16 +15,20 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/rculist.h> #include "ima.h" #include "ima_template_lib.h" -static struct ima_template_desc defined_templates[] = { +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 struct ima_template_field supported_fields[] = { {.field_id = "d", .field_init = ima_eventdigest_init, .field_show = ima_show_template_digest}, @@ -37,6 +41,7 @@ static struct ima_template_field supported_fields[] = { {.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); @@ -52,6 +57,8 @@ static int __init ima_template_setup(char *str) if (ima_template) return 1; + ima_init_template_list(); + /* * Verify that a template with the supplied name exists. * If not, use CONFIG_IMA_DEFAULT_TEMPLATE. @@ -80,7 +87,7 @@ __setup("ima_template=", ima_template_setup); static int __init ima_template_fmt_setup(char *str) { - int num_templates = ARRAY_SIZE(defined_templates); + int num_templates = ARRAY_SIZE(builtin_templates); if (ima_template) return 1; @@ -91,22 +98,28 @@ static int __init ima_template_fmt_setup(char *str) return 1; } - defined_templates[num_templates - 1].fmt = str; - ima_template = defined_templates + num_templates - 1; + builtin_templates[num_templates - 1].fmt = str; + ima_template = builtin_templates + num_templates - 1; + return 1; } __setup("ima_template_fmt=", ima_template_fmt_setup); static struct ima_template_desc *lookup_template_desc(const char *name) { - int i; - - for (i = 0; i < ARRAY_SIZE(defined_templates); i++) { - if (strcmp(defined_templates[i].name, name) == 0) - return defined_templates + i; + 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; + } } - - return NULL; + rcu_read_unlock(); + return found ? template_desc : NULL; } static struct ima_template_field *lookup_template_field(const char *field_id) @@ -142,9 +155,14 @@ static int template_desc_init_fields(const char *template_fmt, { const char *template_fmt_ptr; struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX]; - int template_num_fields = template_fmt_size(template_fmt); + 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); @@ -182,11 +200,28 @@ static int template_desc_init_fields(const char *template_fmt, 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) + if (!ima_template) { + ima_init_template_list(); ima_template = lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE); + } return ima_template; } @@ -205,3 +240,239 @@ int __init ima_init_template(void) 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) +{ + struct binary_field_data { + u32 len; + u8 data[0]; + } __packed; + + struct binary_field_data *field_data; + int offset = 0; + int ret = 0; + int i; + + *entry = kzalloc(sizeof(**entry) + + template_desc->num_fields * sizeof(struct ima_field_data), + GFP_NOFS); + if (!*entry) + return -ENOMEM; + + (*entry)->template_desc = template_desc; + for (i = 0; i < template_desc->num_fields; i++) { + field_data = template_data + offset; + + /* Each field of the template data is prefixed with a length. */ + if (offset > (template_data_size - sizeof(*field_data))) { + pr_err("Restoring the template field failed\n"); + ret = -EINVAL; + break; + } + offset += sizeof(*field_data); + + if (ima_canonical_fmt) + field_data->len = le32_to_cpu(field_data->len); + + if (offset > (template_data_size - field_data->len)) { + pr_err("Restoring the template field data failed\n"); + ret = -EINVAL; + break; + } + offset += field_data->len; + + (*entry)->template_data[i].len = field_data->len; + (*entry)->template_data_len += sizeof(field_data->len); + + (*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, field_data->data, + 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) +{ + struct binary_hdr_v1 { + u32 pcr; + u8 digest[TPM_DIGEST_SIZE]; + u32 template_name_len; + char template_name[0]; + } __packed; + char template_name[MAX_TEMPLATE_NAME_LEN]; + + struct binary_data_v1 { + u32 template_data_size; + char template_data[0]; + } __packed; + + struct ima_kexec_hdr *khdr = buf; + struct binary_hdr_v1 *hdr_v1; + struct binary_data_v1 *data_v1; + + void *bufp = buf + sizeof(*khdr); + void *bufendp; + struct ima_template_entry *entry; + struct ima_template_desc *template_desc; + 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; + } + + /* + * 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)) { + hdr_v1 = bufp; + if (bufp > (bufendp - sizeof(*hdr_v1))) { + pr_err("attempting to restore partial measurement\n"); + ret = -EINVAL; + break; + } + bufp += sizeof(*hdr_v1); + + if (ima_canonical_fmt) + hdr_v1->template_name_len = + le32_to_cpu(hdr_v1->template_name_len); + + if ((hdr_v1->template_name_len >= MAX_TEMPLATE_NAME_LEN) || + (bufp > (bufendp - hdr_v1->template_name_len))) { + pr_err("attempting to restore a template name \ + that is too long\n"); + ret = -EINVAL; + break; + } + data_v1 = bufp += (u_int8_t)hdr_v1->template_name_len; + + /* template name is not null terminated */ + memcpy(template_name, hdr_v1->template_name, + hdr_v1->template_name_len); + template_name[hdr_v1->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; + } + + if (bufp > (bufendp - sizeof(data_v1->template_data_size))) { + pr_err("restoring the template data size failed\n"); + ret = -EINVAL; + break; + } + bufp += (u_int8_t) sizeof(data_v1->template_data_size); + + if (ima_canonical_fmt) + data_v1->template_data_size = + le32_to_cpu(data_v1->template_data_size); + + if (bufp > (bufendp - data_v1->template_data_size)) { + pr_err("restoring the template data failed\n"); + ret = -EINVAL; + break; + } + bufp += data_v1->template_data_size; + + ret = ima_restore_template_data(template_desc, + data_v1->template_data, + data_v1->template_data_size, + &entry); + if (ret < 0) + break; + + memcpy(entry->digest, hdr_v1->digest, TPM_DIGEST_SIZE); + entry->pcr = + !ima_canonical_fmt ? hdr_v1->pcr : le32_to_cpu(hdr_v1->pcr); + ret = ima_restore_measurement_entry(entry); + if (ret < 0) + break; + + } + return ret; +} |