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#define _XOPEN_SOURCE 500
#include <assert.h>
#include <pwd.h>
#include <security/pam_appl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wlr/util/log.h>
#include <xkbcommon/xkbcommon.h>
#include "swaylock/swaylock.h"
#include "swaylock/seat.h"
#include "unicode.h"
static int function_conversation(int num_msg, const struct pam_message **msg,
struct pam_response **resp, void *data) {
struct swaylock_password *pw = data;
/* PAM expects an array of responses, one for each message */
struct pam_response *pam_reply = calloc(
num_msg, sizeof(struct pam_response));
*resp = pam_reply;
for (int i = 0; i < num_msg; ++i) {
switch (msg[i]->msg_style) {
case PAM_PROMPT_ECHO_OFF:
case PAM_PROMPT_ECHO_ON:
pam_reply[i].resp = strdup(pw->buffer); // PAM clears and frees this
break;
case PAM_ERROR_MSG:
case PAM_TEXT_INFO:
break;
}
}
return PAM_SUCCESS;
}
void clear_password_buffer(struct swaylock_password *pw) {
// Use volatile keyword so so compiler can't optimize this out.
volatile char *buffer = pw->buffer;
volatile char zero = '\0';
for (size_t i = 0; i < sizeof(buffer); ++i) {
buffer[i] = zero;
}
pw->len = 0;
}
static bool attempt_password(struct swaylock_password *pw) {
struct passwd *passwd = getpwuid(getuid());
char *username = passwd->pw_name;
const struct pam_conv local_conversation = {
function_conversation, pw
};
pam_handle_t *local_auth_handle = NULL;
int pam_err;
// TODO: only call pam_start once. keep the same handle the whole time
if ((pam_err = pam_start("swaylock", username,
&local_conversation, &local_auth_handle)) != PAM_SUCCESS) {
wlr_log(L_ERROR, "PAM returned error %d", pam_err);
}
if ((pam_err = pam_authenticate(local_auth_handle, 0)) != PAM_SUCCESS) {
wlr_log(L_ERROR, "pam_authenticate failed");
goto fail;
}
// TODO: only call pam_end once we succeed at authing. refresh tokens beforehand
if ((pam_err = pam_end(local_auth_handle, pam_err)) != PAM_SUCCESS) {
wlr_log(L_ERROR, "pam_end failed");
goto fail;
}
clear_password_buffer(pw);
return true;
fail:
clear_password_buffer(pw);
return false;
}
static bool backspace(struct swaylock_password *pw) {
if (pw->len != 0) {
pw->buffer[--pw->len] = 0;
return true;
}
return false;
}
static void append_ch(struct swaylock_password *pw, uint32_t codepoint) {
size_t utf8_size = utf8_chsize(codepoint);
if (pw->len + utf8_size + 1 >= sizeof(pw->buffer)) {
// TODO: Display error
return;
}
utf8_encode(&pw->buffer[pw->len], codepoint);
pw->buffer[pw->len + utf8_size] = 0;
pw->len += utf8_size;
}
void swaylock_handle_key(struct swaylock_state *state,
xkb_keysym_t keysym, uint32_t codepoint) {
switch (keysym) {
case XKB_KEY_KP_Enter: /* fallthrough */
case XKB_KEY_Return:
state->auth_state = AUTH_STATE_VALIDATING;
render_frames(state);
wl_display_roundtrip(state->display);
if (attempt_password(&state->password)) {
state->run_display = false;
break;
}
state->auth_state = AUTH_STATE_INVALID;
render_frames(state);
break;
case XKB_KEY_BackSpace:
if (backspace(&state->password)) {
state->auth_state = AUTH_STATE_BACKSPACE;
render_frames(state);
}
break;
default:
if (codepoint) {
append_ch(&state->password, codepoint);
state->auth_state = AUTH_STATE_INPUT;
render_frames(state);
}
break;
}
}
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