/*
* security/tomoyo/condition.c
*
* Copyright (C) 2005-2011 NTT DATA CORPORATION
*/
#include "common.h"
#include <linux/slab.h>
/* List of "struct tomoyo_condition". */
LIST_HEAD(tomoyo_condition_list);
/**
* tomoyo_same_condition - Check for duplicated "struct tomoyo_condition" entry.
*
* @a: Pointer to "struct tomoyo_condition".
* @b: Pointer to "struct tomoyo_condition".
*
* Returns true if @a == @b, false otherwise.
*/
static inline bool tomoyo_same_condition(const struct tomoyo_condition *a,
const struct tomoyo_condition *b)
{
return a->size == b->size && a->condc == b->condc &&
a->numbers_count == b->numbers_count &&
!memcmp(a + 1, b + 1, a->size - sizeof(*a));
}
/**
* tomoyo_condition_type - Get condition type.
*
* @word: Keyword string.
*
* Returns one of values in "enum tomoyo_conditions_index" on success,
* TOMOYO_MAX_CONDITION_KEYWORD otherwise.
*/
static u8 tomoyo_condition_type(const char *word)
{
u8 i;
for (i = 0; i < TOMOYO_MAX_CONDITION_KEYWORD; i++) {
if (!strcmp(word, tomoyo_condition_keyword[i]))
break;
}
return i;
}
/* Define this to enable debug mode. */
/* #define DEBUG_CONDITION */
#ifdef DEBUG_CONDITION
#define dprintk printk
#else
#define dprintk(...) do { } while (0)
#endif
/**
* tomoyo_commit_condition - Commit "struct tomoyo_condition".
*
* @entry: Pointer to "struct tomoyo_condition".
*
* Returns pointer to "struct tomoyo_condition" on success, NULL otherwise.
*
* This function merges duplicated entries. This function returns NULL if
* @entry is not duplicated but memory quota for policy has exceeded.
*/
static struct tomoyo_condition *tomoyo_commit_condition
(struct tomoyo_condition *entry)
{
struct tomoyo_condition *ptr;
bool found = false;
if (mutex_lock_interruptible(&tomoyo_policy_lock)) {
dprintk(KERN_WARNING "%u: %s failed\n", __LINE__, __func__);
ptr = NULL;
found = true;
goto out;
}
list_for_each_entry_rcu(ptr, &tomoyo_condition_list, head.list) {
if (!tomoyo_same_condition(ptr, entry))
continue;
/* Same entry found. Share this entry. */
atomic_inc(&ptr->head.users);
found = true;
break;
}
if (!found) {
if (tomoyo_memory_ok(entry)) {
atomic_set(&entry->head.users, 1);
list_add_rcu(&entry->head.list,
&tomoyo_condition_list);
} else {
found = true;
ptr = NULL;
}
}
mutex_unlock(&tomoyo_policy_lock);
out:
if (found) {
tomoyo_del_condition(&entry->head.list);
kfree(entry);
entry = ptr;
}
return entry;
}
/**
* tomoyo_get_condition - Parse condition part.
*
* @param: Pointer to "struct tomoyo_acl_param".
*
* Returns pointer to "struct tomoyo_condition" on success, NULL otherwise.
*/
struct tomoyo_condition *tomoyo_get_condition(struct tomoyo_acl_param *param)
{
struct tomoyo_condition *entry = NULL;
struct tomoyo_condition_element *condp = NULL;
struct tomoyo_number_union *numbers_p = NULL;
struct tomoyo_condition e = { };
char * const start_of_string = param->data;
char * const end_of_string = start_of_string + strlen(start_of_string);
char *pos;
rerun:
pos = start_of_string;
while (1) {
u8 left = -1;
u8 right = -1;
char *left_word = pos;
char *cp;
char *right_word;
bool is_not;
if (!*left_word)
break;
/*
* Since left-hand condition does not allow use of "path_group"
* or "number_group" and environment variable's names do not
* accept '=', it is guaranteed that the original line consists
* of one or more repetition of $left$operator$right blocks
* where "$left is free from '=' and ' '" and "$operator is
* either '=' or '!='" and "$right is free from ' '".
* Therefore, we can reconstruct the original line at the end
* of dry run even if we overwrite $operator with '\0'.
*/
cp = strchr(pos, ' ');
if (cp) {
*cp = '\0'; /* Will restore later. */
pos = cp + 1;
} else {
pos = "";
}
right_word = strchr(left_word, '=');
if (!right_word || right_word == left_word)
goto out;
is_not = *(right_word - 1) == '!';
if (is_not)
*(right_word++ - 1) = '\0'; /* Will restore later. */
else if (*(right_word + 1) != '=')
*right_word++ = '\0'; /* Will restore later. */
else
goto out;
dprintk(KERN_WARNING "%u: <%s>%s=<%s>\n", __LINE__, left_word,
is_not ? "!" : "", right_word);
left = tomoyo_condition_type(left_word);
dprintk(KERN_WARNING "%u: <%s> left=%u\n", __LINE__, left_word,
left);
if (left == TOMOYO_MAX_CONDITION_KEYWORD) {
if (!numbers_p) {
e.numbers_count++;
} else {
e.numbers_count--;
left = TOMOYO_NUMBER_UNION;
param->data = left_word;
if (*left_word == '@' ||
!tomoyo_parse_number_union(param,
numbers_p++))
goto out;
}
}
if (!condp)
e.condc++;
else
e.condc--;
right = tomoyo_condition_type(right_word);
if (right == TOMOYO_MAX_CONDITION_KEYWORD) {
if (!numbers_p) {
e.numbers_count++;
} else {
e.numbers_count--;
right = TOMOYO_NUMBER_UNION;
param->data = right_word;
if (!tomoyo_parse_number_union(param,
numbers_p++))
goto out;
}
}
if (!condp) {
dprintk(KERN_WARNING "%u: dry_run left=%u right=%u "
"match=%u\n", __LINE__, left, right, !is_not);
continue;
}
condp->left = left;
condp->right = right;
condp->equals = !is_not;
dprintk(KERN_WARNING "%u: left=%u right=%u match=%u\n",
__LINE__, condp->left, condp->right,
condp->equals);
condp++;
}
dprintk(KERN_INFO "%u: cond=%u numbers=%u\n",
__LINE__, e.condc, e.numbers_count);
if (entry) {
BUG_ON(e.numbers_count | e.condc);
return tomoyo_commit_condition(entry);
}
e.size = sizeof(*entry)
+ e.condc * sizeof(struct tomoyo_condition_element)
+ e.numbers_count * sizeof(struct tomoyo_number_union);
entry = kzalloc(e.size, GFP_NOFS);
if (!entry)
return NULL;
*entry = e;
condp = (struct tomoyo_condition_element *) (entry + 1);
numbers_p = (struct tomoyo_number_union *) (condp + e.condc);
{
bool flag = false;
for (pos = start_of_string; pos < end_of_string; pos++) {
if (*pos)
continue;
if (flag) /* Restore " ". */
*pos = ' ';
else if (*(pos + 1) == '=') /* Restore "!=". */
*pos = '!';
else /* Restore "=". */
*pos = '=';
flag = !flag;
}
}
goto rerun;
out:
dprintk(KERN_WARNING "%u: %s failed\n", __LINE__, __func__);
if (entry) {
tomoyo_del_condition(&entry->head.list);
kfree(entry);
}
return NULL;
}
/**
* tomoyo_condition - Check condition part.
*
* @r: Pointer to "struct tomoyo_request_info".
* @cond: Pointer to "struct tomoyo_condition". Maybe NULL.
*
* Returns true on success, false otherwise.
*
* Caller holds tomoyo_read_lock().
*/
bool tomoyo_condition(struct tomoyo_request_info *r,
const struct tomoyo_condition *cond)
{
u32 i;
unsigned long min_v[2] = { 0, 0 };
unsigned long max_v[2] = { 0, 0 };
const struct tomoyo_condition_element *condp;
const struct tomoyo_number_union *numbers_p;
u16 condc;
if (!cond)
return true;
condc = cond->condc;
condp = (struct tomoyo_condition_element *) (cond + 1);
numbers_p = (const struct tomoyo_number_union *) (condp + condc);
for (i = 0; i < condc; i++) {
const bool match = condp->equals;
const u8 left = condp->left;
const u8 right = condp->right;
u8 j;
condp++;
/* Check numeric or bit-op expressions. */
for (j = 0; j < 2; j++) {
const u8 index = j ? right : left;
unsigned long value = 0;
switch (index) {
case TOMOYO_TASK_UID:
value = current_uid();
break;
case TOMOYO_TASK_EUID:
value = current_euid();
break;
case TOMOYO_TASK_SUID:
value = current_suid();
break;
case TOMOYO_TASK_FSUID:
value = current_fsuid();
break;
case TOMOYO_TASK_GID:
value = current_gid();
break;
case TOMOYO_TASK_EGID:
value = current_egid();
break;
case TOMOYO_TASK_SGID:
value = current_sgid();
break;
case TOMOYO_TASK_FSGID:
value = current_fsgid();
break;
case TOMOYO_TASK_PID:
value = tomoyo_sys_getpid();
break;
case TOMOYO_TASK_PPID:
value = tomoyo_sys_getppid();
break;
case TOMOYO_NUMBER_UNION:
/* Fetch values later. */
break;
default:
break;
}
max_v[j] = value;
min_v[j] = value;
}
if (left == TOMOYO_NUMBER_UNION) {
/* Fetch values now. */
const struct tomoyo_number_union *ptr = numbers_p++;
min_v[0] = ptr->values[0];
max_v[0] = ptr->values[1];
}
if (right == TOMOYO_NUMBER_UNION) {
/* Fetch values now. */
const struct tomoyo_number_union *ptr = numbers_p++;
if (ptr->group) {
if (tomoyo_number_matches_group(min_v[0],
max_v[0],
ptr->group)
== match)
continue;
} else {
if ((min_v[0] <= ptr->values[1] &&
max_v[0] >= ptr->values[0]) == match)
continue;
}
goto out;
}
/* Normal value range comparison. */
if ((min_v[0] <= max_v[1] && max_v[0] >= min_v[1]) == match)
continue;
out:
return false;
}
return true;
}
