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>hifive-unleashed-5.1
Roberto Sassu
Mimi Zohar
parent
adf53a778a
commit
3ce1217d6c
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@ -6,5 +6,5 @@
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obj-$(CONFIG_IMA) += ima.o
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ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
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ima_policy.o ima_template.o
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ima_policy.o ima_template.o ima_template_lib.o
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ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o
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@ -39,6 +39,9 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
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#define IMA_TEMPLATE_FIELD_ID_MAX_LEN 16
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#define IMA_TEMPLATE_NUM_FIELDS_MAX 15
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#define IMA_TEMPLATE_IMA_NAME "ima"
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#define IMA_TEMPLATE_IMA_FMT "d|n"
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/* set during initialization */
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extern int ima_initialized;
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extern int ima_used_chip;
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@ -105,6 +108,8 @@ int __init ima_calc_boot_aggregate(struct ima_digest_data *hash);
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void ima_add_violation(struct file *file, const unsigned char *filename,
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const char *op, const char *cause);
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int ima_init_crypto(void);
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void ima_putc(struct seq_file *m, void *data, int datalen);
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void ima_print_digest(struct seq_file *m, u8 *digest, int size);
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int ima_init_template(void);
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@ -99,7 +99,7 @@ static void ima_measurements_stop(struct seq_file *m, void *v)
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{
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}
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static void ima_putc(struct seq_file *m, void *data, int datalen)
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void ima_putc(struct seq_file *m, void *data, int datalen)
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{
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while (datalen--)
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seq_putc(m, *(char *)data++);
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@ -167,7 +167,7 @@ static const struct file_operations ima_measurements_ops = {
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.release = seq_release,
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};
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static void ima_print_digest(struct seq_file *m, u8 *digest, int size)
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void ima_print_digest(struct seq_file *m, u8 *digest, int size)
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{
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int i;
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@ -13,15 +13,20 @@
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* Helpers to manage template descriptors.
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*/
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#include "ima.h"
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#include "ima_template_lib.h"
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static struct ima_template_desc defined_templates[] = {
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{.name = IMA_TEMPLATE_IMA_NAME,.fmt = IMA_TEMPLATE_IMA_FMT},
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};
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static struct ima_template_field supported_fields[] = {
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{.field_id = "d",.field_init = ima_eventdigest_init,
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.field_show = ima_show_template_digest},
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{.field_id = "n",.field_init = ima_eventname_init,
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.field_show = ima_show_template_string},
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};
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static struct ima_template_field *ima_lookup_template_field(
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const char *field_id)
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static struct ima_template_field *lookup_template_field(const char *field_id)
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{
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int i;
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@ -32,7 +37,7 @@ static struct ima_template_field *ima_lookup_template_field(
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return NULL;
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}
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static int ima_template_fmt_size(char *template_fmt)
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static int template_fmt_size(char *template_fmt)
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{
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char c;
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int template_fmt_len = strlen(template_fmt);
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@ -53,7 +58,7 @@ static int template_desc_init_fields(char *template_fmt,
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int *num_fields)
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{
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char *c, *template_fmt_ptr = template_fmt;
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int template_num_fields = ima_template_fmt_size(template_fmt);
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int template_num_fields = template_fmt_size(template_fmt);
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int i, result = 0;
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if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX)
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@ -66,7 +71,7 @@ static int template_desc_init_fields(char *template_fmt,
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}
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for (i = 0; (c = strsep(&template_fmt_ptr, "|")) != NULL &&
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i < template_num_fields; i++) {
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struct ima_template_field *f = ima_lookup_template_field(c);
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struct ima_template_field *f = lookup_template_field(c);
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if (!f) {
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result = -ENOENT;
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@ -0,0 +1,193 @@
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/*
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* Copyright (C) 2013 Politecnico di Torino, Italy
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* TORSEC group -- http://security.polito.it
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*
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* Author: Roberto Sassu <roberto.sassu@polito.it>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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* File: ima_template_lib.c
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* Library of supported template fields.
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*/
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#include "ima_template_lib.h"
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enum data_formats { DATA_FMT_DIGEST = 0, DATA_FMT_EVENT_NAME, DATA_FMT_STRING };
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static int ima_write_template_field_data(const void *data, const u32 datalen,
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enum data_formats datafmt,
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struct ima_field_data *field_data)
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{
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u8 *buf, *buf_ptr;
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u32 buflen;
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switch (datafmt) {
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case DATA_FMT_EVENT_NAME:
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buflen = IMA_EVENT_NAME_LEN_MAX + 1;
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break;
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case DATA_FMT_STRING:
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buflen = datalen + 1;
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break;
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default:
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buflen = datalen;
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}
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buf = kzalloc(buflen, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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memcpy(buf, data, datalen);
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/*
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* Replace all space characters with underscore for event names and
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* strings. This avoid that, during the parsing of a measurements list,
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* filenames with spaces or that end with the suffix ' (deleted)' are
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* split into multiple template fields (the space is the delimitator
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* character for measurements lists in ASCII format).
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*/
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if (datafmt == DATA_FMT_EVENT_NAME || datafmt == DATA_FMT_STRING) {
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for (buf_ptr = buf; buf_ptr - buf < datalen; buf_ptr++)
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if (*buf_ptr == ' ')
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*buf_ptr = '_';
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}
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field_data->data = buf;
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field_data->len = buflen;
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return 0;
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}
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static void ima_show_template_data_ascii(struct seq_file *m,
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enum ima_show_type show,
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enum data_formats datafmt,
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struct ima_field_data *field_data)
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{
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switch (datafmt) {
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case DATA_FMT_DIGEST:
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ima_print_digest(m, field_data->data, field_data->len);
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break;
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case DATA_FMT_STRING:
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seq_printf(m, "%s", field_data->data);
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break;
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default:
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break;
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}
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}
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static void ima_show_template_data_binary(struct seq_file *m,
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enum ima_show_type show,
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enum data_formats datafmt,
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struct ima_field_data *field_data)
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{
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ima_putc(m, &field_data->len, sizeof(u32));
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if (!field_data->len)
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return;
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ima_putc(m, field_data->data, field_data->len);
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}
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static void ima_show_template_field_data(struct seq_file *m,
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enum ima_show_type show,
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enum data_formats datafmt,
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struct ima_field_data *field_data)
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{
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switch (show) {
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case IMA_SHOW_ASCII:
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ima_show_template_data_ascii(m, show, datafmt, field_data);
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break;
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case IMA_SHOW_BINARY:
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ima_show_template_data_binary(m, show, datafmt, field_data);
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break;
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default:
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break;
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}
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}
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void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data)
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{
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ima_show_template_field_data(m, show, DATA_FMT_DIGEST, field_data);
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}
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void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data)
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{
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ima_show_template_field_data(m, show, DATA_FMT_STRING, field_data);
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}
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/*
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* This function writes the digest of an event.
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*/
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int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
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const unsigned char *filename,
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struct ima_field_data *field_data)
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{
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struct {
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struct ima_digest_data hdr;
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char digest[IMA_MAX_DIGEST_SIZE];
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} hash;
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u8 *cur_digest = hash.hdr.digest;
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u32 cur_digestsize = IMA_DIGEST_SIZE;
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struct inode *inode;
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int result;
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memset(&hash, 0, sizeof(hash));
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if (!iint) /* recording a violation. */
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goto out;
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if (iint->ima_hash->algo == ima_hash_algo) {
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cur_digest = iint->ima_hash->digest;
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cur_digestsize = iint->ima_hash->length;
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goto out;
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}
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if (!file) /* missing info to re-calculate the digest */
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return -EINVAL;
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inode = file_inode(file);
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hash.hdr.algo = ima_hash_algo;
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result = ima_calc_file_hash(file, &hash.hdr);
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if (result) {
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integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
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filename, "collect_data",
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"failed", result, 0);
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return result;
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}
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out:
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return ima_write_template_field_data(cur_digest, cur_digestsize,
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DATA_FMT_DIGEST, field_data);
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}
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/*
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* This function writes the name of an event.
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*/
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int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
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const unsigned char *filename,
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struct ima_field_data *field_data)
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{
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const char *cur_filename = NULL;
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u32 cur_filename_len = 0;
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BUG_ON(filename == NULL && file == NULL);
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if (filename) {
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cur_filename = filename;
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cur_filename_len = strlen(filename);
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if (cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
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goto out;
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}
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if (file) {
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cur_filename = file->f_dentry->d_name.name;
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cur_filename_len = strlen(cur_filename);
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} else
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/*
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* Truncate filename if the latter is too long and
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* the file descriptor is not available.
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*/
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cur_filename_len = IMA_EVENT_NAME_LEN_MAX;
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out:
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return ima_write_template_field_data(cur_filename, cur_filename_len,
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DATA_FMT_EVENT_NAME, field_data);
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}
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@ -0,0 +1,31 @@
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/*
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* Copyright (C) 2013 Politecnico di Torino, Italy
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* TORSEC group -- http://security.polito.it
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*
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* Author: Roberto Sassu <roberto.sassu@polito.it>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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* File: ima_template_lib.h
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* Header for the library of supported template fields.
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*/
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#ifndef __LINUX_IMA_TEMPLATE_LIB_H
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#define __LINUX_IMA_TEMPLATE_LIB_H
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#include <linux/seq_file.h>
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#include "ima.h"
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void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data);
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void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data);
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int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
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const unsigned char *filename,
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struct ima_field_data *field_data);
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int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
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const unsigned char *filename,
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struct ima_field_data *field_data);
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#endif /* __LINUX_IMA_TEMPLATE_LIB_H */
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