ukui-biometric-auth/pam-biometric/pam_biometric.c

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2022-06-02 16:34:46 +08:00
/*
* Copyright (C) 2018 Tianjin KYLIN Information Technology Co., Ltd.
*
* 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; either version 3, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
**/
#define PAM_SM_AUTH
#include "generic.h"
#include <stdio.h>
#include <unistd.h>
#include <pwd.h>
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <security/pam_ext.h>
#include <signal.h>
#include <errno.h>
/* Declare log function */
extern int enable_debug;
extern char *log_prefix;
extern int logger(char *format, ...);
static int ukui_biometric_lock = 0;
int enable_biometric_authentication(pam_handle_t *pamh);
int enable_qrcode_authentication(pam_handle_t *pamh);
int enable_biometric_auth_double();
/* GUI child process alive status */
static int child_alive = 1;
/* Signal handler */
static void signal_handler(int signo)
{
if (signo == SIGUSR1)
child_alive = 0; /* GUI child process has terminated */
logger("signal_handler is triggered\n");
}
/*
* Check if the service should use biometric authentication
*/
int service_filter(char *service)
{
if (strcmp(service, "lightdm") == 0) {
int ret = system("/bin/chmod -f a+wr /tmp/bio.log");
(void)ret; /* Suppress gcc ignoring return value warning */
return 1;
}
if (strcmp(service, "ukui-screensaver-qt") == 0)
return 1;
if (strcmp(service, "sudo") == 0)
return 1;
if (strcmp(service, "login") == 0)
return 1;
if (strcmp(service, "su") == 0)
return 1;
// if (strcmp(service, "mate-screensaver") == 0)
// return 1;
if (strcmp(service, "polkit-1") == 0)
return 1;
#ifdef ENABLE_BIOTEST
if (strcmp(service, "biotest") == 0)
return 1;
#endif
return 0;
}
/*
* Invoke the PAM conversation function
*/
int call_conversation(pam_handle_t *pamh, int msg_style, char *msg, char *resp)
{
/* PAM data structures used by conversation */
const struct pam_message *message[1] = {0};
struct pam_message *message_tmp = 0;
struct pam_response *response = 0;
const struct pam_conv *conv_struct = 0;
int status = -1;
status = pam_get_item(pamh, PAM_CONV, (const void **)&conv_struct);
if (status != PAM_SUCCESS)
return PAM_SYSTEM_ERR;
message_tmp = (struct pam_message *)malloc(sizeof(struct pam_message));
message_tmp->msg_style = msg_style;
message_tmp->msg = msg;
message[0] = message_tmp;
logger("Call conv callback function\n");
status = conv_struct->conv(1, message, &response, conv_struct->appdata_ptr);
logger("Finish conv callback function\n");
if (resp)
strcpy(resp, response->resp);
/* Use typecast to suppress gcc warnings */
free((void *)message[0]);
if (response)
free(response->resp);
free(response);
return status;
}
/* GUI child process */
void child(char *service, char *username, char *xdisp)
{
char *gui = "/usr/bin/bioauth";
logger("Child process will be replaced.\n");
int fd = open("/dev/null", O_WRONLY);
dup2(fd, 2);
execl(gui, "bioauth",
"--service", service,
"--user", username,
// "--display", xdisp,
enable_debug ? "--debug" : "",
(char *)0);
/*
* execl almost always succeed as long as the GUI executable file exists.
* Though invoking GUI under console will exit with error, the GUI child
* process won't reach here. Therefore, the following code won't be
* executed in general.
*/
logger("Fatal error: execl(gui) failed in child process. "
"This is an extremely rare condition. Please ensure that the "
"biometric-authentication executable file exists.\n");
logger("Use password as a fallback\n");
logger("Child _exit with BIO_IGNORE\n");
/* Child process exits */
_exit(BIO_IGNORE);
}
void handler()
{
return;
}
/* PAM parent process */
int parent(int pid, pam_handle_t *pamh, int need_call_conv)
{
logger("Parent process continue running.\n");
int child_status = -1;
/*
* 1. If calling conversation function is not needed, wait the child
* until it exits.
* 2. Otherwise, send a text info to application at first and then
* call the conversation function to request the password. The returned
* password is unused.
* Note: During requesting the password, screensaver won't display the
* prompting message, while greeter will display it into the password
* entry. If there is a "\n" at the end of the message, it will be
* displayed on the Label above the password entry.
*/
if (need_call_conv) {
char *lang = getenv("LANG");
char *msg1, *msg2;
if (lang && !strncmp(lang, "zh_CN", 5))
msg1 = "请进行生物识别或点击“切换到密码登录”\n";
else
msg1 = "Use biometric authentication or click "
"\"Switch to password\"\n";
#ifdef EMPTY_PAM_PWD_PROMPT
msg2 = "";
#else
msg2 = "pam_biometric.so needs a fake ENTER:";
#endif
if (signal(SIGUSR1, signal_handler) == SIG_ERR)
logger("Fatal Error. Can't catch SIGUSR1\n");
reinvoke:
call_conversation(pamh, PAM_TEXT_INFO, msg1, NULL);
call_conversation(pamh, PAM_PROMPT_ECHO_OFF, msg2, NULL);
/* GUI child process is still alive. This enter is typed by user. */
if (child_alive == 1)
goto reinvoke;
signal(SIGUSR1, SIG_DFL);
waitpid(pid, &child_status, 0);
} else {
logger("Waiting for the GUI child process to exit...\n");
//由于sudo命令在进入pam认证时会阻塞来自终端的SIGINT以及SIGQUIT信号导致使用
//pam认证时按下Ctrl+C无反应认证完成后sudo会退出这里为了简单取消了阻塞
//信号,捕获信号但不做处理,在认证完成后,恢复原本阻塞状态
sigset_t mask;
sigprocmask(SIG_BLOCK,NULL,&mask);
sigprocmask(SIG_UNBLOCK,&mask,NULL);
signal(SIGINT,handler);
waitpid(pid, &child_status, 0);
logger("GUI child process has exited.\n");
sigprocmask(SIG_SETMASK,&mask,NULL);
}
/*
* Determine the return value of PAM according to the return value of
* child process.
*/
int bio_result = BIO_ERROR; /* biometric result code */
if (WIFEXITED(child_status))
bio_result = WEXITSTATUS(child_status);
else /* This may be because the GUI child process is invoked under console. */
logger("The GUI-Child process terminate abnormally.\n");
if (bio_result == BIO_SUCCESS) {
if(!enable_biometric_authentication(pamh) && !enable_qrcode_authentication(pamh)) {
logger("disable biometric authentication.\n");
return PAM_SYSTEM_ERR;
}
logger("pam_biometric.so return PAM_SUCCESS\n");
return PAM_SUCCESS;
} else if (bio_result == BIO_IGNORE) {
/* Override msg1 to empty the label. We are ready to enter the password module. */
call_conversation(pamh, PAM_TEXT_INFO, "", NULL);
ukui_biometric_lock = 1;
logger("pam_biometric.so return PAM_IGNORE\n");
return PAM_IGNORE;
} else {
logger("pam_biometric.so return PAM_SYSTEM_ERR\n");
ukui_biometric_lock = 1;
return PAM_SYSTEM_ERR;
}
}
/* Set environment variables related to displaying */
void check_and_set_env(pam_handle_t *pamh, char **xdisp, char **xauth)
{
*xdisp=getenv("DISPLAY");
*xauth=getenv("XAUTHORITY");
if (*xdisp == 0){
pam_get_item(pamh, PAM_XDISPLAY, (const void **)xdisp);
if (*xdisp)
setenv("DISPLAY",*xdisp,-1);
}
if (*xauth == 0)
setenv("XAUTHORITY", "/var/run/lightdm/root/:0", -1);
*xdisp=getenv("DISPLAY");
*xauth=getenv("XAUTHORITY");
if (*xdisp == 0)
logger("Warning: DISPLAY env is still empty, "
"this is not an error if you are using terminal\n");
if (*xauth == 0)
logger("Warning: XAUTHORITY env is still empty, "
"this is not an error if you are using terminal\n");
}
/* Biometric processing function for generic purpose */
int biometric_auth_independent(pam_handle_t *pamh , char *service, int need_call_conv)
{
/* Get the username */
char *username = 0;
pam_get_item(pamh, PAM_USER, (const void **)&username);
/* Check and set environment variables */
char *xdisp, *xauth;
check_and_set_env(pamh, &xdisp, &xauth);
/* Detach child process */
unsigned int pid;
pid = fork();
if (pid == 0 ) {
child(service, username, xdisp);
logger("Should never reach here.\n");
return PAM_SYSTEM_ERR;
} else if (pid > 0) {
return parent(pid, pamh, need_call_conv);
} else {
logger("Fork Error!\n");
return PAM_SYSTEM_ERR;
}
}
/* Biometric processing function fot polkit-1 */
int biometric_auth_polkit()
{
logger("Current service is polkit-1\n");
const char *fifo_name = "/tmp/bio.fifo";
if(access(fifo_name, F_OK) == -1) {
int res = mkfifo(fifo_name, 0777);
if(res != 0) {
logger("Can't create FIFO file\n");
return PAM_SYSTEM_ERR;
}
}
int fifo_rd = open(fifo_name, O_RDONLY);
if (fifo_rd == -1)
return PAM_SYSTEM_ERR;
logger("Before reading FIFO\n");
char buffer[8] = {0};
if(read(fifo_rd, buffer, 8) == -1)
return PAM_SYSTEM_ERR;
logger("After reading FIFO\n");
int result_code;
sscanf(buffer, "%d", &result_code);
remove(fifo_name);
if (result_code == BIO_SUCCESS) {
logger("pam_biometric.so return PAM_SUCCESS\n");
return PAM_SUCCESS;
} else if (result_code == BIO_IGNORE) {
logger("pam_biometric.so return PAM_IGNORE\n");
return PAM_IGNORE;
} else {
logger("pam_biometric.so return PAM_SYSTEM_ERR\n");
return PAM_SYSTEM_ERR;
}
}
int biometric_auth_embeded(pam_handle_t *pamh)
{
/*
* By convention, PAM module sends a string "BIOMETRIC_PAM" to
* lightdm and this message will be forwarded to greeter. After
* the authentication is completed, greeter will send a string
* "BIOMETRIC_IGNORE"/"BIOMETRIC_SUCCESS" to lightdm and then it
* will be forwarded to PAM module. We can get the authentication
* status by comparing strings.
*/
char resp[96] = {0};
if(enable_biometric_auth_double())
call_conversation(pamh, PAM_PROMPT_ECHO_OFF, BIOMETRIC_PAM_DOUBLE, resp);
else
call_conversation(pamh, PAM_PROMPT_ECHO_OFF, BIOMETRIC_PAM, resp);
if (strcmp(resp, BIOMETRIC_IGNORE) == 0)
return PAM_IGNORE;
else if (strcmp(resp, BIOMETRIC_SUCCESS) == 0){
if(!enable_biometric_authentication(pamh) && !enable_qrcode_authentication(pamh)) {
logger("disable biometric authentication.\n");
return PAM_SYSTEM_ERR;
}
return PAM_SUCCESS;
}
else if (strcmp(resp, BIOMETRIC_FAILED) == 0)
return PAM_AUTH_ERR;
else
return PAM_SYSTEM_ERR;
}
void get_greeter_session(char buf[], int len)
{
FILE *stream;
char cmd[] = "ps -aux | grep greeter-session | grep -v grep | awk '{print $13}' | awk -F '/' '{print $4}'";
memset(buf, 0, len);
stream = popen(cmd, "r");
if(fgets(buf, len, stream) == NULL)
logger("get greeter session error: %d\n", errno);
buf[strlen(buf)-1] = '\0';
if(strlen(buf) == 0) {
char cmd1[] = "ps aux | grep ukui-greeter | grep -v grep | wc -l";
pclose(stream);
stream = popen(cmd1, "r");
if(fgets(buf, len, stream) == NULL)
logger("get greeter session error: %d\n", errno);
int i = atoi(buf);
if(i > 0)
strcpy(buf, "ukui-greeter");
}
pclose(stream);
}
int enable_by_polkit()
{
FILE *file;
char buf[1024];
if( (file = fopen(BIO_COM_FILE, "r")) == NULL) {
logger("open communication file failed: %s\n", strerror(errno));
return 0;
}
memset(buf, 0, sizeof(buf));
fgets(buf, sizeof(buf), file);
fclose(file);
if(remove(BIO_COM_FILE) < 0)
logger("remove communication file failed: %s\n", strerror(errno));
logger("%s\n", buf);
if(strcmp(buf, "polkit-ukui-authentication-agent-1") == 0)
return 1;
return 0;
}
int enable_biometric_authentication(pam_handle_t *pamh)
{
char conf_file[] = GET_STR(CONFIG_FILE);
FILE *file;
char line[1024], is_enable[16];
int i;
if((file = fopen(conf_file, "r")) == NULL){
logger("open configure file failed: %s\n", strerror(errno));
return 0;
}
while(fgets(line, sizeof(line), file)) {
i = sscanf(line, "EnableAuth=%s\n", is_enable);
if(i > 0) {
logger("EnableAuth=%s\n", is_enable);
break;
}
}
fclose(file);
if(!strcmp(is_enable, "true"))
return 1;
return 0;
}
int enable_qrcode_authentication(pam_handle_t *pamh)
{
char conf_file[] = GET_STR(CONFIG_FILE);
FILE *file;
char line[1024], is_enable[16];
int i;
if((file = fopen(conf_file, "r")) == NULL){
logger("open configure file failed: %s\n", strerror(errno));
return 0;
}
while(fgets(line, sizeof(line), file)) {
i = sscanf(line, "EnableQRCode=%s\n", is_enable);
if(i > 0) {
logger("EnableQRCode=%s\n", is_enable);
break;
}
}
fclose(file);
if(!strcmp(is_enable, "true"))
return 1;
return 0;
}
int enable_biometric_auth_double()
{
char conf_file[] = GET_STR(CONFIG_FILE);
FILE *file;
char line[1024], is_enable[16];
int i;
if((file = fopen(conf_file, "r")) == NULL){
logger("open configure file failed: %s\n", strerror(errno));
return 0;
}
while(fgets(line, sizeof(line), file)) {
i = sscanf(line, "DoubleAuth=%s\n", is_enable);
if(i > 0) {
logger("DoubleAuth=%s\n", is_enable);
break;
}
}
fclose(file);
if(!strcmp(is_enable, "true"))
return 1;
return 0;
}
/*
* SPI interface
*/
int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc,
const char **argv)
{
for(int i = 0; i < argc; i++) {
if(strcmp(argv[i], "debug") == 0) {
enable_debug = 1;
log_prefix = "PAM_BIO";
}
}
logger("Invoke libpam_biometric.so module\n");
char *service = 0;
if((!enable_biometric_authentication(pamh) && !enable_qrcode_authentication(pamh)) || ukui_biometric_lock) {
logger("disable biometric authentication.\n");
return PAM_IGNORE;
}
logger("enable biometric authentication.\n");
pam_get_item(pamh, PAM_SERVICE, (const void **)&service);
/* Service filter */
if (!service_filter(service)){
logger("Service <%s> should not use biometric-authentication\n", service);
return PAM_IGNORE;
}
/* Different services use different processing function */
if (strcmp(service, "lightdm") == 0) {
char buf[128];
get_greeter_session(buf, sizeof(buf));
logger("current greeter: %s\n", buf);
if(strcmp(buf, "ukui-greeter") == 0 || strcmp(buf, "ukui-greeter-wayland") == 0)
return biometric_auth_embeded(pamh);
// else
// return biometric_auth_independent(pamh, "lightdm", 1);
}
else if (strcmp(service, "ukui-screensaver-qt")==0)
return biometric_auth_embeded(pamh);
else if (strcmp(service, "polkit-1") == 0){
if(enable_by_polkit())
return biometric_auth_embeded(pamh);
else
logger("[PAM_BIOMETRIC]: It's not polkit-ukui-authentication-agent-1.\n");
}
else if (strcmp(service, "sudo") == 0)
return biometric_auth_independent(pamh, "sudo", 0);
else if (strcmp(service, "login") == 0)
return biometric_auth_independent(pamh, "login", 0);
else if (strcmp(service, "su") == 0)
return biometric_auth_independent(pamh, "su", 0);
// else if (strcmp(service, "mate-screensaver") == 0)
// return biometric_auth_independent(pamh, "mate-screensaver", 1);
#ifdef ENABLE_BIOTEST
else if (strcmp(service, "biotest") == 0)
return biometric_auth_independent(pamh, "biotest", 1);
#endif
else
logger("Service <%s> slip through the service filter\n", service);
return PAM_IGNORE;
}
int
pam_sm_setcred (pam_handle_t *pamh, int flags ,
int argc , const char **argv )
{
return PAM_SUCCESS;
}