212 lines
5.3 KiB
C
212 lines
5.3 KiB
C
/*
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* This file Copyright (C) 2016 Mnemosyne LLC
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*
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* It may be used under the GNU GPL versions 2 or 3
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* or any future license endorsed by Mnemosyne LLC.
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*
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*/
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#include <string.h>
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#include <time.h>
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#ifndef _WIN32
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#include <sys/stat.h>
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#endif
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#include "transmission.h"
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#include "crypto-utils.h"
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#include "error.h"
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#include "error-types.h"
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#include "file.h"
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#include "log.h"
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#include "platform.h"
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#include "session-id.h"
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#include "utils.h"
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#define SESSION_ID_SIZE 48
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#define SESSION_ID_DURATION_SEC (60 * 60) /* expire in an hour */
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struct tr_session_id
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{
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char* current_value;
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char* previous_value;
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tr_sys_file_t current_lock_file;
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tr_sys_file_t previous_lock_file;
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time_t expires_at;
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};
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static char* generate_new_session_id_value(void)
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{
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char const pool[] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
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size_t const pool_size = sizeof(pool) - 1;
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char* buf = tr_new(char, SESSION_ID_SIZE + 1);
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tr_rand_buffer(buf, SESSION_ID_SIZE);
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for (size_t i = 0; i < SESSION_ID_SIZE; ++i)
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{
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buf[i] = pool[(unsigned char)buf[i] % pool_size];
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}
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buf[SESSION_ID_SIZE] = '\0';
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return buf;
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}
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static char* get_session_id_lock_file_path(char const* session_id)
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{
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char* lock_file_dir = tr_getSessionIdDir();
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char* lock_file_path = tr_strdup_printf("%s/tr_session_id_%s", lock_file_dir, session_id);
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tr_free(lock_file_dir);
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return lock_file_path;
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}
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static tr_sys_file_t create_session_id_lock_file(char const* session_id)
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{
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if (session_id == NULL)
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{
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return TR_BAD_SYS_FILE;
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}
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char* lock_file_path = get_session_id_lock_file_path(session_id);
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tr_sys_file_t lock_file;
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tr_error* error = NULL;
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lock_file = tr_sys_file_open(lock_file_path, TR_SYS_FILE_READ | TR_SYS_FILE_WRITE | TR_SYS_FILE_CREATE, 0600, &error);
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if (lock_file != TR_BAD_SYS_FILE)
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{
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if (tr_sys_file_lock(lock_file, TR_SYS_FILE_LOCK_EX | TR_SYS_FILE_LOCK_NB, &error))
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{
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#ifndef _WIN32
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/* Allow any user to lock the file regardless of current umask */
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fchmod(lock_file, 0644);
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#endif
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}
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else
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{
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tr_sys_file_close(lock_file, NULL);
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lock_file = TR_BAD_SYS_FILE;
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}
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}
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if (error != NULL)
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{
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tr_logAddError("Unable to create session lock file (%d): %s", error->code, error->message);
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tr_error_free(error);
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}
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tr_free(lock_file_path);
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return lock_file;
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}
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static void destroy_session_id_lock_file(tr_sys_file_t lock_file, char const* session_id)
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{
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if (lock_file != TR_BAD_SYS_FILE)
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{
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tr_sys_file_close(lock_file, NULL);
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}
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if (session_id != NULL)
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{
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char* lock_file_path = get_session_id_lock_file_path(session_id);
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tr_sys_path_remove(lock_file_path, NULL);
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tr_free(lock_file_path);
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}
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}
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tr_session_id_t tr_session_id_new(void)
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{
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tr_session_id_t const session_id = tr_new0(struct tr_session_id, 1);
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session_id->current_lock_file = TR_BAD_SYS_FILE;
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session_id->previous_lock_file = TR_BAD_SYS_FILE;
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return session_id;
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}
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void tr_session_id_free(tr_session_id_t session_id)
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{
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if (session_id == NULL)
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{
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return;
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}
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destroy_session_id_lock_file(session_id->previous_lock_file, session_id->previous_value);
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destroy_session_id_lock_file(session_id->current_lock_file, session_id->current_value);
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tr_free(session_id->previous_value);
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tr_free(session_id->current_value);
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tr_free(session_id);
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}
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char const* tr_session_id_get_current(tr_session_id_t session_id)
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{
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time_t const now = tr_time();
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if (session_id->current_value == NULL || now >= session_id->expires_at)
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{
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destroy_session_id_lock_file(session_id->previous_lock_file, session_id->previous_value);
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tr_free(session_id->previous_value);
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session_id->previous_value = session_id->current_value;
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session_id->current_value = generate_new_session_id_value();
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session_id->previous_lock_file = session_id->current_lock_file;
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session_id->current_lock_file = create_session_id_lock_file(session_id->current_value);
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session_id->expires_at = now + SESSION_ID_DURATION_SEC;
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}
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return session_id->current_value;
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}
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bool tr_session_id_is_local(char const* session_id)
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{
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bool ret = false;
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if (session_id != NULL)
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{
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char* lock_file_path = get_session_id_lock_file_path(session_id);
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tr_sys_file_t lock_file;
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tr_error* error = NULL;
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lock_file = tr_sys_file_open(lock_file_path, TR_SYS_FILE_READ, 0, &error);
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if (lock_file == TR_BAD_SYS_FILE)
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{
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if (TR_ERROR_IS_ENOENT(error->code))
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{
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tr_error_clear(&error);
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}
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}
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else
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{
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if (!tr_sys_file_lock(lock_file, TR_SYS_FILE_LOCK_SH | TR_SYS_FILE_LOCK_NB, &error) &&
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#ifndef _WIN32
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(error->code == EWOULDBLOCK))
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#else
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(error->code == ERROR_LOCK_VIOLATION))
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#endif
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{
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ret = true;
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tr_error_clear(&error);
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}
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tr_sys_file_close(lock_file, NULL);
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}
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if (error != NULL)
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{
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tr_logAddError("Unable to open session lock file (%d): %s", error->code, error->message);
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tr_error_free(error);
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}
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tr_free(lock_file_path);
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}
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return ret;
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}
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