Verify passwords

1 files changed, 57 insertions, 1 deletions

diff --git a/swaylock/password.c b/swaylock/password.c
index da67205d..9af7fe16 100644
--- a/swaylock/password.c
+++ b/swaylock/password.c
@@ -1,4 +1,6 @@
 #include <assert.h>
+#include <pwd.h>
+#include <security/pam_appl.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <wlr/util/log.h>
@@ -7,6 +9,58 @@
 #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 = pw->buffer;
+                        break;
+                case PAM_ERROR_MSG:
+                case PAM_TEXT_INFO:
+                        break;
+                }
+        }
+        return PAM_SUCCESS;
+}
+
+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;
+        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;
+        }
+        if ((pam_err = pam_end(local_auth_handle, pam_err)) != PAM_SUCCESS) {
+                wlr_log(L_ERROR, "pam_end failed");
+                goto fail;
+        }
+        // PAM freed this
+        pw->buffer = NULL;
+        pw->len = pw->size = 0;
+        return true;
+fail:
+        // PAM freed this
+        pw->buffer = NULL;
+        pw->len = pw->size = 0;
+        return false;
+}
+
 static void backspace(struct swaylock_password *pw) {
         if (pw->len != 0) {
                 pw->buffer[--pw->len] = 0;
@@ -43,7 +97,9 @@ void swaylock_handle_key(struct swaylock_state *state,
         switch (keysym) {
                 case XKB_KEY_KP_Enter: /* fallthrough */
                 case XKB_KEY_Return:
-                        // TODO: Attempt password
+                        if (attempt_password(&state->password)) {
+                                exit(0);
+                        }
                         break;
                 case XKB_KEY_BackSpace:
                         backspace(&state->password);