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ima: switch to new template management mechanism 

This patch performs the switch to the new template mechanism by modifying
the functions ima_alloc_init_template(), ima_measurements_show() and
ima_ascii_measurements_show(). The old function ima_template_show() was
removed as it is no longer needed. Also, if the template descriptor used
to generate a measurement entry is not 'ima', the whole length of field
data stored for an entry is provided before the data itself through the
binary_runtime_measurement interface.

Changelog:
- unnecessary to use strncmp() (Mimi Zohar)
- create new variable 'field' in ima_alloc_init_template() (Roberto Sassu)
- use GFP_NOFS flag in ima_alloc_init_template() (Roberto Sassu)
- new variable 'num_fields' in ima_store_template() (Roberto Sassu,
  proposed by Mimi Zohar)
- rename ima_calc_buffer_hash/template_hash() to ima_calc_field_array_hash(),
  something more generic (Mimi, requested by Dmitry)
- sparse error fix - Fengguang Wu
- fix lindent warnings
- always include the field length in the template data length
- include the template field length variable size in the template data length
- include both the template field data and field length in the template digest
  calculation. Simplifies verifying the template digest. (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 12:16:33 +02:00 committed by Mimi Zohar
parent 4d7aeee73f
commit a71dc65d30
5 changed files with 107 additions and 97 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
security/integrity/ima/ima.h
View File

@ -72,17 +72,11 @@ struct ima_template_desc {
struct ima_template_field **fields;
};
/* IMA inode template definition */
struct ima_template_data {
u8 digest[IMA_DIGEST_SIZE]; /* sha1/md5 measurement hash */
char file_name[IMA_EVENT_NAME_LEN_MAX + 1]; /* name + \0 */
};
struct ima_template_entry {
u8 digest[TPM_DIGEST_SIZE]; /* sha1 or md5 measurement hash */
const char *template_name;
int template_len;
struct ima_template_data template;
struct ima_template_desc *template_desc; /* template descriptor */
u32 template_data_len;
struct ima_field_data template_data[0]; /* template related data */
};
struct ima_queue_entry {
@ -102,14 +96,16 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
const char *op, struct inode *inode,
const unsigned char *filename);
int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash);
int ima_calc_buffer_hash(const void *data, int len,
struct ima_digest_data *hash);
int ima_calc_field_array_hash(struct ima_field_data *field_data, int num_fields,
struct ima_digest_data *hash);
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);
struct ima_template_desc *ima_template_desc_current(void);
int ima_init_template(void);
int ima_init_template(void);
@ -146,7 +142,6 @@ int ima_alloc_init_template(struct integrity_iint_cache *iint,
struct ima_template_entry **entry);
int ima_store_template(struct ima_template_entry *entry, int violation,
struct inode *inode, const unsigned char *filename);
void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show);
const char *ima_d_path(struct path *path, char **pathbuf);
/* rbtree tree calls to lookup, insert, delete

75
security/integrity/ima/ima_api.c
View File

@ -21,8 +21,6 @@
#include <crypto/hash_info.h>
#include "ima.h"
static const char *IMA_TEMPLATE_NAME = "ima";
/*
* ima_alloc_init_template - create and initialize a new template entry
*/
@ -30,52 +28,32 @@ int ima_alloc_init_template(struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct ima_template_entry **entry)
{
struct ima_template_entry *e;
int result = 0;
struct ima_template_desc *template_desc = ima_template_desc_current();
int i, result = 0;
e = kzalloc(sizeof(**entry), GFP_NOFS);
if (!e)
*entry = kzalloc(sizeof(**entry) + template_desc->num_fields *
sizeof(struct ima_field_data), GFP_NOFS);
if (!*entry)
return -ENOMEM;
memset(&(e)->template, 0, sizeof(e->template));
if (!iint) /* IMA measurement violation entry */
goto out;
for (i = 0; i < template_desc->num_fields; i++) {
struct ima_template_field *field = template_desc->fields[i];
u32 len;
if (iint->ima_hash->algo != ima_hash_algo) {
struct inode *inode;
struct {
struct ima_digest_data hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} hash;
result = field->field_init(iint, file, filename,
&((*entry)->template_data[i]));
if (result != 0)
goto out;
if (!file) {
result = -EINVAL;
goto out_free;
}
inode = file_inode(file);
hash.hdr.algo = ima_hash_algo;
hash.hdr.length = SHA1_DIGEST_SIZE;
result = ima_calc_file_hash(file, &hash.hdr);
if (result) {
integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
filename, "collect_data",
"failed", result, 0);
goto out_free;
} else
memcpy(e->template.digest, hash.hdr.digest,
hash.hdr.length);
} else
memcpy(e->template.digest, iint->ima_hash->digest,
iint->ima_hash->length);
out:
strcpy(e->template.file_name,
(strlen(filename) > IMA_EVENT_NAME_LEN_MAX && file != NULL) ?
file->f_dentry->d_name.name : filename);
*entry = e;
len = (*entry)->template_data[i].len;
(*entry)->template_data_len += sizeof(len);
(*entry)->template_data_len += len;
}
(*entry)->template_desc = template_desc;
return 0;
out_free:
kfree(e);
out:
kfree(*entry);
*entry = NULL;
return result;
}
@ -101,24 +79,23 @@ int ima_store_template(struct ima_template_entry *entry,
{
const char *op = "add_template_measure";
const char *audit_cause = "hashing_error";
char *template_name = entry->template_desc->name;
int result;
struct {
struct ima_digest_data hdr;
char digest[TPM_DIGEST_SIZE];
} hash;
memset(entry->digest, 0, sizeof(entry->digest));
entry->template_name = IMA_TEMPLATE_NAME;
entry->template_len = sizeof(entry->template);
if (!violation) {
int num_fields = entry->template_desc->num_fields;
/* this function uses default algo */
hash.hdr.algo = HASH_ALGO_SHA1;
result = ima_calc_buffer_hash(&entry->template,
entry->template_len, &hash.hdr);
result = ima_calc_field_array_hash(&entry->template_data[0],
num_fields, &hash.hdr);
if (result < 0) {
integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode,
entry->template_name, op,
template_name, op,
audit_cause, result, 0);
return result;
}

34
security/integrity/ima/ima_crypto.c
View File

@ -137,26 +137,46 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
}
/*
* Calculate the hash of a given buffer
* Calculate the hash of template data
*/
static int ima_calc_buffer_hash_tfm(const void *buf, int len,
struct ima_digest_data *hash,
struct crypto_shash *tfm)
static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
int num_fields,
struct ima_digest_data *hash,
struct crypto_shash *tfm)
{
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(tfm)];
} desc;
int rc, i;
desc.shash.tfm = tfm;
desc.shash.flags = 0;
hash->length = crypto_shash_digestsize(tfm);
return crypto_shash_digest(&desc.shash, buf, len, hash->digest);
rc = crypto_shash_init(&desc.shash);
if (rc != 0)
return rc;
for (i = 0; i < num_fields; i++) {
rc = crypto_shash_update(&desc.shash,
(const u8 *) &field_data[i].len,
sizeof(field_data[i].len));
rc = crypto_shash_update(&desc.shash, field_data[i].data,
field_data[i].len);
if (rc)
break;
}
if (!rc)
rc = crypto_shash_final(&desc.shash, hash->digest);
return rc;
}
int ima_calc_buffer_hash(const void *buf, int len, struct ima_digest_data *hash)
int ima_calc_field_array_hash(struct ima_field_data *field_data, int num_fields,
struct ima_digest_data *hash)
{
struct crypto_shash *tfm;
int rc;
@ -165,7 +185,7 @@ int ima_calc_buffer_hash(const void *buf, int len, struct ima_digest_data *hash)
if (IS_ERR(tfm))
return PTR_ERR(tfm);
rc = ima_calc_buffer_hash_tfm(buf, len, hash, tfm);
rc = ima_calc_field_array_hash_tfm(field_data, num_fields, hash, tfm);
ima_free_tfm(tfm);

54
security/integrity/ima/ima_fs.c
View File

@ -110,6 +110,7 @@ void ima_putc(struct seq_file *m, void *data, int datalen)
* char[20]=template digest
* 32bit-le=template name size
* char[n]=template name
* [eventdata length]
* eventdata[n]=template specific data
*/
static int ima_measurements_show(struct seq_file *m, void *v)
@ -119,6 +120,7 @@ static int ima_measurements_show(struct seq_file *m, void *v)
struct ima_template_entry *e;
int namelen;
u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
int i;
/* get entry */
e = qe->entry;
@ -136,15 +138,22 @@ static int ima_measurements_show(struct seq_file *m, void *v)
ima_putc(m, e->digest, TPM_DIGEST_SIZE);
/* 3rd: template name size */
namelen = strlen(e->template_name);
namelen = strlen(e->template_desc->name);
ima_putc(m, &namelen, sizeof namelen);
/* 4th: template name */
ima_putc(m, (void *)e->template_name, namelen);
ima_putc(m, e->template_desc->name, namelen);
/* 5th: template specific data */
ima_template_show(m, (struct ima_template_data *)&e->template,
IMA_SHOW_BINARY);
/* 5th: template length (except for 'ima' template) */
if (strcmp(e->template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0)
ima_putc(m, &e->template_data_len,
sizeof(e->template_data_len));
/* 6th: template specific data */
for (i = 0; i < e->template_desc->num_fields; i++) {
e->template_desc->fields[i]->field_show(m, IMA_SHOW_BINARY,
&e->template_data[i]);
}
return 0;
}
@ -175,33 +184,13 @@ void ima_print_digest(struct seq_file *m, u8 *digest, int size)
seq_printf(m, "%02x", *(digest + i));
}
void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show)
{
struct ima_template_data *entry = e;
int namelen;
switch (show) {
case IMA_SHOW_ASCII:
ima_print_digest(m, entry->digest, IMA_DIGEST_SIZE);
seq_printf(m, " %s\n", entry->file_name);
break;
case IMA_SHOW_BINARY:
ima_putc(m, entry->digest, IMA_DIGEST_SIZE);
namelen = strlen(entry->file_name);
ima_putc(m, &namelen, sizeof namelen);
ima_putc(m, entry->file_name, namelen);
default:
break;
}
}
/* print in ascii */
static int ima_ascii_measurements_show(struct seq_file *m, void *v)
{
/* the list never shrinks, so we don't need a lock here */
struct ima_queue_entry *qe = v;
struct ima_template_entry *e;
int i;
/* get entry */
e = qe->entry;
@ -215,11 +204,18 @@ static int ima_ascii_measurements_show(struct seq_file *m, void *v)
ima_print_digest(m, e->digest, TPM_DIGEST_SIZE);
/* 3th: template name */
seq_printf(m, " %s ", e->template_name);
seq_printf(m, " %s", e->template_desc->name);
/* 4th: template specific data */
ima_template_show(m, (struct ima_template_data *)&e->template,
IMA_SHOW_ASCII);
for (i = 0; i < e->template_desc->num_fields; i++) {
seq_puts(m, " ");
if (e->template_data[i].len == 0)
continue;
e->template_desc->fields[i]->field_show(m, IMA_SHOW_ASCII,
&e->template_data[i]);
}
seq_puts(m, "\n");
return 0;
}

22
security/integrity/ima/ima_template.c
View File

@ -31,6 +31,20 @@ static struct ima_template_field supported_fields[] = {
.field_show = ima_show_template_string},
};
static struct ima_template_desc *ima_template;
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;
}
return NULL;
}
static struct ima_template_field *lookup_template_field(const char *field_id)
{
int i;
@ -110,6 +124,14 @@ static int init_defined_templates(void)
return result;
}
struct ima_template_desc *ima_template_desc_current(void)
{
if (!ima_template)
ima_template = lookup_template_desc(IMA_TEMPLATE_IMA_NAME);
return ima_template;
}
int ima_init_template(void)
{
int result;