ima: define template fields library and new helpers

This patch defines a library containing two initial template fields,
inode digest (d) and file name (n), the 'ima' template descriptor,
whose format is 'd|n', and two helper functions,
ima_write_template_field_data() and ima_show_template_field_data().

Changelog:
- replace ima_eventname_init() parameter NULL checking with BUG_ON.
  (suggested by Mimi)
- include "new template fields for inode digest (d) and file name (n)"
  definitions to fix a compiler warning.  - Mimi
- unnecessary to prefix static function names with 'ima_'. remove
  prefix to resolve Lindent formatting changes. - Mimi
- abbreviated/removed inline comments - Mimi
- always send the template field length - Mimi

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
This commit is contained in:
Roberto Sassu 2013-06-07 12:16:30 +02:00 committed by Mimi Zohar
parent adf53a778a
commit 3ce1217d6c
6 changed files with 242 additions and 8 deletions

View file

@ -6,5 +6,5 @@
obj-$(CONFIG_IMA) += ima.o
ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
ima_policy.o ima_template.o
ima_policy.o ima_template.o ima_template_lib.o
ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o

View file

@ -39,6 +39,9 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
#define IMA_TEMPLATE_FIELD_ID_MAX_LEN 16
#define IMA_TEMPLATE_NUM_FIELDS_MAX 15
#define IMA_TEMPLATE_IMA_NAME "ima"
#define IMA_TEMPLATE_IMA_FMT "d|n"
/* set during initialization */
extern int ima_initialized;
extern int ima_used_chip;
@ -105,6 +108,8 @@ int __init ima_calc_boot_aggregate(struct ima_digest_data *hash);
void ima_add_violation(struct file *file, const unsigned char *filename,
const char *op, const char *cause);
int ima_init_crypto(void);
void ima_putc(struct seq_file *m, void *data, int datalen);
void ima_print_digest(struct seq_file *m, u8 *digest, int size);
int ima_init_template(void);

View file

@ -99,7 +99,7 @@ static void ima_measurements_stop(struct seq_file *m, void *v)
{
}
static void ima_putc(struct seq_file *m, void *data, int datalen)
void ima_putc(struct seq_file *m, void *data, int datalen)
{
while (datalen--)
seq_putc(m, *(char *)data++);
@ -167,7 +167,7 @@ static const struct file_operations ima_measurements_ops = {
.release = seq_release,
};
static void ima_print_digest(struct seq_file *m, u8 *digest, int size)
void ima_print_digest(struct seq_file *m, u8 *digest, int size)
{
int i;

View file

@ -13,15 +13,20 @@
* Helpers to manage template descriptors.
*/
#include "ima.h"
#include "ima_template_lib.h"
static struct ima_template_desc defined_templates[] = {
{.name = IMA_TEMPLATE_IMA_NAME,.fmt = IMA_TEMPLATE_IMA_FMT},
};
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},
};
static struct ima_template_field *ima_lookup_template_field(
const char *field_id)
static struct ima_template_field *lookup_template_field(const char *field_id)
{
int i;
@ -32,7 +37,7 @@ static struct ima_template_field *ima_lookup_template_field(
return NULL;
}
static int ima_template_fmt_size(char *template_fmt)
static int template_fmt_size(char *template_fmt)
{
char c;
int template_fmt_len = strlen(template_fmt);
@ -53,7 +58,7 @@ static int template_desc_init_fields(char *template_fmt,
int *num_fields)
{
char *c, *template_fmt_ptr = template_fmt;
int template_num_fields = ima_template_fmt_size(template_fmt);
int template_num_fields = template_fmt_size(template_fmt);
int i, result = 0;
if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX)
@ -66,7 +71,7 @@ static int template_desc_init_fields(char *template_fmt,
}
for (i = 0; (c = strsep(&template_fmt_ptr, "|")) != NULL &&
i < template_num_fields; i++) {
struct ima_template_field *f = ima_lookup_template_field(c);
struct ima_template_field *f = lookup_template_field(c);
if (!f) {
result = -ENOENT;

View file

@ -0,0 +1,193 @@
/*
* 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_lib.c
* Library of supported template fields.
*/
#include "ima_template_lib.h"
enum data_formats { DATA_FMT_DIGEST = 0, DATA_FMT_EVENT_NAME, DATA_FMT_STRING };
static int ima_write_template_field_data(const void *data, const u32 datalen,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
u8 *buf, *buf_ptr;
u32 buflen;
switch (datafmt) {
case DATA_FMT_EVENT_NAME:
buflen = IMA_EVENT_NAME_LEN_MAX + 1;
break;
case DATA_FMT_STRING:
buflen = datalen + 1;
break;
default:
buflen = datalen;
}
buf = kzalloc(buflen, GFP_KERNEL);
if (!buf)
return -ENOMEM;
memcpy(buf, data, datalen);
/*
* Replace all space characters with underscore for event names and
* strings. This avoid that, during the parsing of a measurements list,
* filenames with spaces or that end with the suffix ' (deleted)' are
* split into multiple template fields (the space is the delimitator
* character for measurements lists in ASCII format).
*/
if (datafmt == DATA_FMT_EVENT_NAME || datafmt == DATA_FMT_STRING) {
for (buf_ptr = buf; buf_ptr - buf < datalen; buf_ptr++)
if (*buf_ptr == ' ')
*buf_ptr = '_';
}
field_data->data = buf;
field_data->len = buflen;
return 0;
}
static void ima_show_template_data_ascii(struct seq_file *m,
enum ima_show_type show,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
switch (datafmt) {
case DATA_FMT_DIGEST:
ima_print_digest(m, field_data->data, field_data->len);
break;
case DATA_FMT_STRING:
seq_printf(m, "%s", field_data->data);
break;
default:
break;
}
}
static void ima_show_template_data_binary(struct seq_file *m,
enum ima_show_type show,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
ima_putc(m, &field_data->len, sizeof(u32));
if (!field_data->len)
return;
ima_putc(m, field_data->data, field_data->len);
}
static void ima_show_template_field_data(struct seq_file *m,
enum ima_show_type show,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
switch (show) {
case IMA_SHOW_ASCII:
ima_show_template_data_ascii(m, show, datafmt, field_data);
break;
case IMA_SHOW_BINARY:
ima_show_template_data_binary(m, show, datafmt, field_data);
break;
default:
break;
}
}
void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_DIGEST, field_data);
}
void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_STRING, field_data);
}
/*
* This function writes the digest of an event.
*/
int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data)
{
struct {
struct ima_digest_data hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} hash;
u8 *cur_digest = hash.hdr.digest;
u32 cur_digestsize = IMA_DIGEST_SIZE;
struct inode *inode;
int result;
memset(&hash, 0, sizeof(hash));
if (!iint) /* recording a violation. */
goto out;
if (iint->ima_hash->algo == ima_hash_algo) {
cur_digest = iint->ima_hash->digest;
cur_digestsize = iint->ima_hash->length;
goto out;
}
if (!file) /* missing info to re-calculate the digest */
return -EINVAL;
inode = file_inode(file);
hash.hdr.algo = ima_hash_algo;
result = ima_calc_file_hash(file, &hash.hdr);
if (result) {
integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
filename, "collect_data",
"failed", result, 0);
return result;
}
out:
return ima_write_template_field_data(cur_digest, cur_digestsize,
DATA_FMT_DIGEST, field_data);
}
/*
* This function writes the name of an event.
*/
int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data)
{
const char *cur_filename = NULL;
u32 cur_filename_len = 0;
BUG_ON(filename == NULL && file == NULL);
if (filename) {
cur_filename = filename;
cur_filename_len = strlen(filename);
if (cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
goto out;
}
if (file) {
cur_filename = file->f_dentry->d_name.name;
cur_filename_len = strlen(cur_filename);
} else
/*
* Truncate filename if the latter is too long and
* the file descriptor is not available.
*/
cur_filename_len = IMA_EVENT_NAME_LEN_MAX;
out:
return ima_write_template_field_data(cur_filename, cur_filename_len,
DATA_FMT_EVENT_NAME, field_data);
}

View file

@ -0,0 +1,31 @@
/*
* 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_lib.h
* Header for the library of supported template fields.
*/
#ifndef __LINUX_IMA_TEMPLATE_LIB_H
#define __LINUX_IMA_TEMPLATE_LIB_H
#include <linux/seq_file.h>
#include "ima.h"
void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data);
void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data);
int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data);
int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data);
#endif /* __LINUX_IMA_TEMPLATE_LIB_H */