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ima: define new template ima-ng and template fields d-ng and n-ng
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This patch adds support for the new template 'ima-ng', whose format
is defined as 'd-ng|n-ng'.  These new field definitions remove the
size limitations of the original 'ima' template.  Further, the 'd-ng'
field prefixes the inode digest with the hash algorithim, when
displaying the new larger digest sizes.

Change log:
- scripts/Lindent fixes  - Mimi
- "always true comparison" - reported by Fengguang Wu, resolved Dmitry
- initialize hash_algo variable to HASH_ALGO__LAST
- always prefix digest with hash algorithm - Mimi

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
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Roberto Sassu authored and Mimi Zohar committed Oct 25, 2013
1 parent 3ce1217 commit 4d7aeee
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Showing 3 changed files with 150 additions and 17 deletions.
7 changes: 6 additions & 1 deletion security/integrity/ima/ima_template.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,14 +16,19 @@
#include "ima_template_lib.h"

static struct ima_template_desc defined_templates[] = {
{.name = IMA_TEMPLATE_IMA_NAME,.fmt = IMA_TEMPLATE_IMA_FMT},
{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
{.name = "ima-ng",.fmt = "d-ng|n-ng"},
};

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},
{.field_id = "d-ng",.field_init = ima_eventdigest_ng_init,
.field_show = ima_show_template_digest_ng},
{.field_id = "n-ng",.field_init = ima_eventname_ng_init,
.field_show = ima_show_template_string},
};

static struct ima_template_field *lookup_template_field(const char *field_id)
Expand Down
152 changes: 136 additions & 16 deletions security/integrity/ima/ima_template_lib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,9 +12,25 @@
* File: ima_template_lib.c
* Library of supported template fields.
*/
#include <crypto/hash_info.h>

#include "ima_template_lib.h"

enum data_formats { DATA_FMT_DIGEST = 0, DATA_FMT_EVENT_NAME, DATA_FMT_STRING };
static bool ima_template_hash_algo_allowed(u8 algo)
{
if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_MD5)
return true;

return false;
}

enum data_formats {
DATA_FMT_DIGEST = 0,
DATA_FMT_DIGEST_WITH_ALGO,
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)
Expand Down Expand Up @@ -62,12 +78,22 @@ static void ima_show_template_data_ascii(struct seq_file *m,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
u8 *buf_ptr = field_data->data, buflen = field_data->len;

switch (datafmt) {
case DATA_FMT_DIGEST_WITH_ALGO:
buf_ptr = strnchr(field_data->data, buflen, ':');
if (buf_ptr != field_data->data)
seq_printf(m, "%s", field_data->data);

/* skip ':' and '\0' */
buf_ptr += 2;
buflen -= buf_ptr - field_data->data;
case DATA_FMT_DIGEST:
ima_print_digest(m, field_data->data, field_data->len);
ima_print_digest(m, buf_ptr, buflen);
break;
case DATA_FMT_STRING:
seq_printf(m, "%s", field_data->data);
seq_printf(m, "%s", buf_ptr);
break;
default:
break;
Expand Down Expand Up @@ -108,14 +134,59 @@ void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
ima_show_template_field_data(m, show, DATA_FMT_DIGEST, field_data);
}

void ima_show_template_digest_ng(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_WITH_ALGO,
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);
}

static int ima_eventdigest_init_common(u8 *digest, u32 digestsize, u8 hash_algo,
struct ima_field_data *field_data,
bool size_limit)
{
/*
* digest formats:
* - DATA_FMT_DIGEST: digest
* - DATA_FMT_DIGEST_WITH_ALGO: [<hash algo>] + ':' + '\0' + digest,
* where <hash algo> is provided if the hash algoritm is not
* SHA1 or MD5
*/
u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 };
enum data_formats fmt = DATA_FMT_DIGEST;
u32 offset = 0;

if (!size_limit) {
fmt = DATA_FMT_DIGEST_WITH_ALGO;
if (hash_algo < HASH_ALGO__LAST)
offset += snprintf(buffer, CRYPTO_MAX_ALG_NAME + 1,
"%s", hash_algo_name[hash_algo]);
buffer[offset] = ':';
offset += 2;
}

if (digest)
memcpy(buffer + offset, digest, digestsize);
else
/*
* If digest is NULL, the event being recorded is a violation.
* Make room for the digest by increasing the offset of
* IMA_DIGEST_SIZE.
*/
offset += IMA_DIGEST_SIZE;

return ima_write_template_field_data(buffer, offset + digestsize,
fmt, field_data);
}

/*
* This function writes the digest of an event.
* This function writes the digest of an event (with size limit).
*/
int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
Expand All @@ -125,8 +196,8 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
struct ima_digest_data hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} hash;
u8 *cur_digest = hash.hdr.digest;
u32 cur_digestsize = IMA_DIGEST_SIZE;
u8 *cur_digest = NULL;
u32 cur_digestsize = 0;
struct inode *inode;
int result;

Expand All @@ -135,7 +206,7 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
if (!iint) /* recording a violation. */
goto out;

if (iint->ima_hash->algo == ima_hash_algo) {
if (ima_template_hash_algo_allowed(iint->ima_hash->algo)) {
cur_digest = iint->ima_hash->digest;
cur_digestsize = iint->ima_hash->length;
goto out;
Expand All @@ -145,36 +216,63 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
return -EINVAL;

inode = file_inode(file);
hash.hdr.algo = ima_hash_algo;
hash.hdr.algo = ima_template_hash_algo_allowed(ima_hash_algo) ?
ima_hash_algo : HASH_ALGO_SHA1;
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;
}
cur_digest = hash.hdr.digest;
cur_digestsize = hash.hdr.length;
out:
return ima_write_template_field_data(cur_digest, cur_digestsize,
DATA_FMT_DIGEST, field_data);
return ima_eventdigest_init_common(cur_digest, cur_digestsize, -1,
field_data, true);
}

/*
* This function writes the name of an event.
* This function writes the digest of an event (without size limit).
*/
int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data)
int ima_eventdigest_ng_init(struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct ima_field_data *field_data)
{
u8 *cur_digest = NULL, hash_algo = HASH_ALGO__LAST;
u32 cur_digestsize = 0;

/* If iint is NULL, we are recording a violation. */
if (!iint)
goto out;

cur_digest = iint->ima_hash->digest;
cur_digestsize = iint->ima_hash->length;

hash_algo = iint->ima_hash->algo;
out:
return ima_eventdigest_init_common(cur_digest, cur_digestsize,
hash_algo, field_data, false);
}

static int ima_eventname_init_common(struct integrity_iint_cache *iint,
struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data,
bool size_limit)
{
const char *cur_filename = NULL;
u32 cur_filename_len = 0;
enum data_formats fmt = size_limit ?
DATA_FMT_EVENT_NAME : DATA_FMT_STRING;

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)
if (!size_limit || cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
goto out;
}

Expand All @@ -189,5 +287,27 @@ int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
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);
fmt, field_data);
}

/*
* This function writes the name of an event (with size limit).
*/
int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data)
{
return ima_eventname_init_common(iint, file, filename,
field_data, true);
}

/*
* This function writes the name of an event (without size limit).
*/
int ima_eventname_ng_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data)
{
return ima_eventname_init_common(iint, file, filename,
field_data, false);
}
8 changes: 8 additions & 0 deletions security/integrity/ima/ima_template_lib.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,8 @@

void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data);
void ima_show_template_digest_ng(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,
Expand All @@ -28,4 +30,10 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data);
int ima_eventdigest_ng_init(struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct ima_field_data *field_data);
int ima_eventname_ng_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 */

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