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/*
* 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);
}
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