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be-files.c
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be-files.c
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/*
* Copyright (c) 2017, Diehl Connectivity Solutions GmbH. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer. 2. Redistributions
* in binary form must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution. 3. Neither the name of mosquitto
* nor the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef BE_FILES
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <mosquitto.h>
#include <mosquitto_plugin.h>
#include <mosquitto_broker.h>
#include "log.h"
#include "hash.h"
#include "backends.h"
#include "be-files.h"
#if (LIBMOSQUITTO_MAJOR > 1) || ((LIBMOSQUITTO_MAJOR == 1) && (LIBMOSQUITTO_MINOR >= 4))
#define LOG(lvl, fmt, ...) mosquitto_log_printf(lvl, fmt, ##__VA_ARGS__)
#else
#define LOG(lvl, fmt, ...) _log(lvl, fmt, ##__VA_ARGS__)
#endif
typedef struct dllist_entry {
struct dllist_entry *next;
struct dllist_entry *prev;
} dllist_entry;
typedef struct dllist {
dllist_entry head;
} dllist;
static inline void dllist_entry_init(dllist_entry * thiz)
{
thiz->next = thiz->prev = thiz;
}
static inline void dllist_init(dllist * thiz)
{
dllist_entry_init(&thiz->head);
}
static inline void dllist_entry_remove(dllist_entry * thiz)
{
thiz->next->prev = thiz->prev;
thiz->prev->next = thiz->next;
dllist_entry_init(thiz);
}
static inline void dllist_entry_insert(dllist_entry * thiz, dllist_entry * other)
{
dllist_entry *tmpPrev = thiz;
dllist_entry *tmpNext = thiz->next;
dllist_entry_remove(other);
tmpNext->prev = other;
other->next = tmpNext;
other->prev = tmpPrev;
tmpPrev->next = other;
}
static inline void dllist_push_back(dllist * thiz, dllist_entry * entry)
{
dllist_entry_insert(thiz->head.prev, entry);
}
static inline bool dllist_empty(const dllist * thiz)
{
return (thiz->head.next == &thiz->head);
}
#if !(defined(offsetof))
#if defined(__GNUC__) && __GNUC__ >= 4
#define offsetof(type, member) __builtin_offsetof(type, member)
#else
#define offsetof(type, member) ((size_t)&((type*)NULL)->member)
#endif
#endif
#define dllist_entry_element(ptr, type, member) \
(type*)((char*)(void*)ptr + offsetof(type, member))
#define dllist_for_each_element(thiz, iter, member) \
for((iter) = dllist_entry_element((thiz)->head.next, typeof(*(iter)), member); \
&(iter)->member != &(thiz)->head; \
(iter) = dllist_entry_element((iter)->member.next, typeof(*(iter)), member))
typedef struct acl_entry {
dllist_entry entry;
int access;
char *topic;
} acl_entry;
typedef struct pwd_entry {
dllist_entry entry;
char *username;
char *password;
dllist acl_entries;
} pwd_entry;
typedef struct be_files {
dllist passwords;
bool acl_checks;
} be_files;
static dllist acl_entries = {{&acl_entries.head, &acl_entries.head}};
static pwd_entry *find_pwd(be_files * conf, const char *username)
{
pwd_entry *iter;
dllist_for_each_element(&conf->passwords, iter, entry) {
if (strcmp(username, iter->username) == 0)
return iter;
}
return NULL;
}
static bool read_passwords(be_files * conf, FILE * file)
{
char line[512];
char *pos;
char *username;
char *password;
pwd_entry *entry;
while (fgets(line, sizeof(line), file) != NULL) {
if (line[0] == '#' || line[0] == '\r' || line[0] == '\n')
continue;
pos = strchr(line, ':');
if (pos) {
*pos = '\0';
++pos;
username = line;
password = pos;
pos = strchr(password, '\r');
if (pos != NULL)
*pos = '\0';
pos = strchr(password, '\n');
if (pos != NULL)
*pos = '\0';
entry = (pwd_entry *) malloc(sizeof(pwd_entry));
dllist_entry_init(&entry->entry);
dllist_init(&entry->acl_entries);
entry->username = strdup(username);
entry->password = strdup(password);
dllist_push_back(&conf->passwords, &entry->entry);
}
}
return true;
}
/*
* (read|write)?[ \t]+[^ \t]+
*/
static acl_entry *read_acl_line(const char *line)
{
acl_entry *entry;
const char *pos;
const char *i;
size_t len;
int access;
if (strncmp("read", line, 4) == 0 && (line[4] == ' ' || line[4] == '\t')) {
access = MOSQ_ACL_READ;
pos = &line[5];
for (; (*pos == ' ' || *pos == '\t') && *pos != '\0'; ++pos);
} else if (strncmp("write", line, 5) == 0 && (line[5] == ' ' || line[5] == '\t')) {
access = MOSQ_ACL_WRITE;
pos = &line[6];
for (; (*pos == ' ' || *pos == '\t') && *pos != '\0'; ++pos);
} else {
access = MOSQ_ACL_READ | MOSQ_ACL_WRITE;
pos = &line[0];
}
for (len = 0, i = pos; *i != '\0' && *i != ' ' && *i != '\t' && *i != '\r' && *i != '\n'; ++len, ++i);
entry = (acl_entry *) malloc(sizeof(acl_entry));
dllist_entry_init(&entry->entry);
entry->access = access;
entry->topic = (char *)calloc(len + 1, sizeof(char));
strncpy(entry->topic, pos, len);
entry->topic[len] = '\0';
return entry;
}
/*
* (user)[ \t]+([^ \t]+) (topic|pattern)[ \t]+(read|write)?[ \t][^ \t]+
*/
static bool read_acl(be_files * conf, FILE * file)
{
char line[512];
char *pos;
char *username;
acl_entry *entry;
pwd_entry *pwd = NULL;
while (fgets(line, sizeof(line), file) != NULL) {
if (line[0] == '#')
continue;
for (pos = line; *pos != '\0' && (*pos == ' ' || *pos == '\t'); ++pos);
if (*pos == '\r' || *pos == '\n')
continue;
if (strncmp("user", pos, 4) == 0) {
for (pos = pos + 4; (*pos == ' ' || *pos == '\t') && *pos != '\0'; ++pos);
username = pos;
pos = strchr(username, '\r');
if (pos != NULL)
*pos = '\0';
pos = strchr(username, '\n');
if (pos != NULL)
*pos = '\0';
pwd = find_pwd(conf, username);
if (pwd == NULL) {
pwd = (pwd_entry *) malloc(sizeof(pwd_entry));
dllist_entry_init(&pwd->entry);
dllist_init(&pwd->acl_entries);
pwd->username = strdup(username);
pwd->password = NULL;
dllist_push_back(&conf->passwords, &pwd->entry);
}
} else if (strncmp("topic", pos, 5) == 0) {
for (pos = pos + 5; (*pos == ' ' || *pos == '\t') && *pos != '\0'; ++pos);
entry = read_acl_line(pos);
if (pwd != NULL)
dllist_push_back(&pwd->acl_entries, &entry->entry);
else
dllist_push_back(&acl_entries, &entry->entry);
} else if (strncmp("pattern", pos, 7) == 0) {
for (pos = pos + 7; (*pos == ' ' || *pos == '\t') && *pos != '\0'; ++pos);
entry = read_acl_line(pos);
dllist_push_back(&acl_entries, &entry->entry);
} else {
LOG(MOSQ_LOG_WARNING, "failed to parse line: %s", line);
}
}
return true;
}
void *be_files_init()
{
const char *path;
FILE *file;
be_files *const conf = (be_files *) malloc(sizeof(be_files));
dllist_init(&conf->passwords);
conf->acl_checks = false;
path = p_stab("password_file");
file = (path == NULL) ? NULL : fopen(path, "r");
if (path != NULL && file == NULL) {
LOG(MOSQ_LOG_ERR, "failed to open password file: %s", path);
be_files_destroy(conf);
return NULL;
}
if (file != NULL) {
read_passwords(conf, file);
fclose(file);
}
path = p_stab("acl_file");
conf->acl_checks = path != NULL;
file = (path == NULL) ? NULL : fopen(path, "r");
if (path != NULL && file == NULL) {
LOG(MOSQ_LOG_ERR, "failed to open ACL file: %s", path);
be_files_destroy(conf);
return NULL;
}
if (file != NULL) {
read_acl(conf, file);
fclose(file);
}
return conf;
}
static void free_acl(dllist * list)
{
acl_entry *acl;
while (!dllist_empty(list)) {
acl = dllist_entry_element(list->head.next, acl_entry, entry);
dllist_entry_remove(&acl->entry);
if (acl->topic)
free(acl->topic);
free(acl);
}
}
void be_files_destroy(void *handle)
{
be_files *const conf = (be_files *) handle;
pwd_entry *pwd;
while (!dllist_empty(&conf->passwords)) {
pwd = dllist_entry_element(conf->passwords.head.next, pwd_entry, entry);
dllist_entry_remove(&pwd->entry);
if (pwd->username)
free(pwd->username);
if (pwd->password)
free(pwd->password);
free_acl(&pwd->acl_entries);
free(pwd);
}
free_acl(&acl_entries);
free(conf);
}
int be_files_getuser(void *handle,
const char *username,
const char *password,
char **phash, const char *clientid)
{
be_files *const conf = (be_files *) handle;
pwd_entry *entry = find_pwd(conf, username);
*phash = (entry == NULL || entry->password == NULL) ? NULL : strdup(entry->password);
return BACKEND_DEFER;
}
int be_files_superuser(void *handle, const char *username)
{
return 0;
}
static int do_aclcheck(dllist * acl_list,
const char *clientid,
const char *username,
const char *topic,
int access)
{
char buf[512];
bool ret;
acl_entry *acl;
const char *t;
const char *si;
char *di;
dllist_for_each_element(acl_list, acl, entry) {
for (si = acl->topic, di = buf; *si != '\0';) {
switch (*si) {
case '%':
++si;
switch (*si) {
case 'c':
++si;
for (t = clientid; *t != '\0'; ++di, ++t)
*di = *t;
break;
case 'u':
++si;
for (t = username; *t != '\0'; ++di, ++t)
*di = *t;
break;
default:
*di++ = *si;
break;
}
break;
default:
*di++ = *si++;
break;
}
}
*di = '\0';
if (mosquitto_topic_matches_sub(buf, topic, &ret) != MOSQ_ERR_SUCCESS) {
LOG(MOSQ_LOG_ERR, "invalid topic '%s'", buf);
} else if (ret && (access & acl->access) != 0) {
return BACKEND_ALLOW;
}
}
return BACKEND_DEFER;
}
int be_files_aclcheck(void *handle,
const char *clientid,
const char *username,
const char *topic,
int access)
{
be_files *const conf = (be_files *) handle;
pwd_entry *pwd = find_pwd(conf, username);
int ret = 0;
if (!conf->acl_checks)
return BACKEND_ALLOW;
if (pwd != NULL) {
ret = do_aclcheck(&pwd->acl_entries, clientid, username, topic, access);
}
if (ret == BACKEND_DEFER)
ret = do_aclcheck(&acl_entries, clientid, username, topic, access);
return ret;
}
int be_files_aclpatterns_available(void)
{
return !dllist_empty(&acl_entries);
}
int be_files_aclpatterns_check(const char *clientid,
const char *username,
const char *topic,
int access)
{
return do_aclcheck(&acl_entries, clientid, username, topic, access);
}
#endif /* // BE_FILES */