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				https://github.com/swaywm/sway.git
				synced 2025-11-03 09:01:43 -05:00 
			
		
		
		
	This involves setuid'ing swaylock, which then forks and drops perms on the parent process. The child process remains root and listens on a pipe for requests to validate passwords against /etc/shadow.
		
			
				
	
	
		
			124 lines
		
	
	
	
		
			3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			124 lines
		
	
	
	
		
			3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
#define _XOPEN_SOURCE 500
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#include <assert.h>
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#include <pwd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <wlr/util/log.h>
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#include <xkbcommon/xkbcommon.h>
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#include "swaylock/swaylock.h"
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#include "swaylock/seat.h"
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#include "unicode.h"
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void clear_password_buffer(struct swaylock_password *pw) {
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	// Use volatile keyword so so compiler can't optimize this out.
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	volatile char *buffer = pw->buffer;
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	volatile char zero = '\0';
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	for (size_t i = 0; i < sizeof(buffer); ++i) {
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		buffer[i] = zero;
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	}
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	pw->len = 0;
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}
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static bool backspace(struct swaylock_password *pw) {
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	if (pw->len != 0) {
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		pw->buffer[--pw->len] = 0;
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		return true;
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	}
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	return false;
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}
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static void append_ch(struct swaylock_password *pw, uint32_t codepoint) {
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	size_t utf8_size = utf8_chsize(codepoint);
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	if (pw->len + utf8_size + 1 >= sizeof(pw->buffer)) {
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		// TODO: Display error
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		return;
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	}
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	utf8_encode(&pw->buffer[pw->len], codepoint);
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	pw->buffer[pw->len + utf8_size] = 0;
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	pw->len += utf8_size;
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}
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void swaylock_handle_key(struct swaylock_state *state,
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		xkb_keysym_t keysym, uint32_t codepoint) {
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	switch (keysym) {
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	case XKB_KEY_KP_Enter: /* fallthrough */
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	case XKB_KEY_Return:
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		if (state->args.ignore_empty && state->password.len == 0) {
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			break;
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		}
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		state->auth_state = AUTH_STATE_VALIDATING;
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		damage_state(state);
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		while (wl_display_dispatch(state->display) != -1 && state->run_display) {
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			bool ok = 1;
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			struct swaylock_surface *surface;
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			wl_list_for_each(surface, &state->surfaces, link) {
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				if (surface->dirty) {
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					ok = 0;
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				}
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			}
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			if (ok) {
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				break;
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			}
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		}
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		wl_display_flush(state->display);
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		if (attempt_password(&state->password)) {
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			state->run_display = false;
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			break;
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		}
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		state->auth_state = AUTH_STATE_INVALID;
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		damage_state(state);
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		break;
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	case XKB_KEY_Delete:
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	case XKB_KEY_BackSpace:
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		if (backspace(&state->password)) {
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			state->auth_state = AUTH_STATE_BACKSPACE;
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		} else {
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			state->auth_state = AUTH_STATE_CLEAR;
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		}
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		damage_state(state);
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		break;
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	case XKB_KEY_Escape:
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		clear_password_buffer(&state->password);
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		state->auth_state = AUTH_STATE_CLEAR;
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		damage_state(state);
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		break;
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	case XKB_KEY_Caps_Lock:
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		/* The state is getting active after this
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		 * so we need to manually toggle it */
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		state->xkb.caps_lock = !state->xkb.caps_lock;
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		state->auth_state = AUTH_STATE_INPUT_NOP;
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		damage_state(state);
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		break;
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	case XKB_KEY_Shift_L:
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	case XKB_KEY_Shift_R:
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	case XKB_KEY_Control_L:
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	case XKB_KEY_Control_R:
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	case XKB_KEY_Meta_L:
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	case XKB_KEY_Meta_R:
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	case XKB_KEY_Alt_L:
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	case XKB_KEY_Alt_R:
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	case XKB_KEY_Super_L:
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	case XKB_KEY_Super_R:
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		state->auth_state = AUTH_STATE_INPUT_NOP;
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		damage_state(state);
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		break;
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	case XKB_KEY_u:
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		if (state->xkb.control) {
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			clear_password_buffer(&state->password);
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			state->auth_state = AUTH_STATE_CLEAR;
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			damage_state(state);
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			break;
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		}
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		// fallthrough
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	default:
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		if (codepoint) {
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			append_ch(&state->password, codepoint);
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			state->auth_state = AUTH_STATE_INPUT;
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			damage_state(state);
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		}
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		break;
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	}
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}
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