Commit 3ce1217d authored by Roberto Sassu's avatar Roberto Sassu Committed by Mimi Zohar
Browse files

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: default avatarRoberto Sassu <roberto.sassu@polito.it>
Signed-off-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
parent adf53a77

security/integrity/ima/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

security/integrity/ima/ima.h

+5 −0
Original line number Diff line number Diff line
@@ -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);

security/integrity/ima/ima_fs.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

security/integrity/ima/ima_template.c

+10 −5
Original line number Diff line number Diff line
@@ -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;

security/integrity/ima/ima_template_lib.c

0 → 100644
+193 −0
Original line number Diff line number Diff line 
/*

 * 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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