From 21e7ad34ea33ceb37b7877a0782e33775c295054 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Fri, 30 Apr 2021 11:28:05 +0200
Subject: Try to get password from pwdaemon

---
 src/pwgui/main.cpp | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 73 insertions(+), 1 deletion(-)

diff --git a/src/pwgui/main.cpp b/src/pwgui/main.cpp
index 2c8123b..264f0df 100644
--- a/src/pwgui/main.cpp
+++ b/src/pwgui/main.cpp
@@ -19,6 +19,8 @@
 #include <pwd.h>
 #include <grp.h>
 #include <errno.h>
+#include <sys/socket.h>
+#include <sys/un.h>
 
 #include "../x11workaround.h"
 
@@ -60,7 +62,8 @@ static char *helper_urlencode(char *s, char *enc);
 static int helper_cupsError(const int code);
 static void helper_messageBox(const char *caption, const char *text, const bool error = false);
 
-static void demo();
+static void query_pwdaemon(int pfd, char *creds);
+
 /*
  * Note to the next HiWi who wants to refactor this to use something like boost::program_options:
  * Don't do it unless you are certain that you understood the behaviour described here:
@@ -203,6 +206,7 @@ int main(int argc, char *argv[])
 	// Seems we need the dialog
 	int status;
 	char *pass = NULL;
+	int numRun = 0;
 
 
 	do {
@@ -219,6 +223,11 @@ int main(int argc, char *argv[])
 			close(pfd[0]);
 			helper_dropprivs();
 			helper_copyenv(NULL);
+			// .... but first, try pwdaemon
+			if (numRun == 0) {
+				query_pwdaemon(pfd[1], creds);
+				// if the function returned, nothing was queried and we should show the gui
+			}
 			QApplication a(argc, argv);
 			Backdrop *bg = new Backdrop;
 			bg->show();
@@ -232,6 +241,7 @@ int main(int argc, char *argv[])
 			exit(a.exec());
 			return CUPS_BACKEND_CANCEL;
 		}
+		numRun++;
 		// Main (Parent)
 		close(pfd[1]);
 		// Read from pipe
@@ -670,3 +680,65 @@ static void helper_messageBox(const char *caption, const char *text, const bool
 	// Wait for child to die
 	waitpid(pid, NULL, 0);
 }
+
+static void query_pwdaemon(int pfd, char *creds)
+{
+	char homedir[NAMELEN];
+	char daemon_data[NAMELEN];
+	char *e = getenv("HOME");
+	if (e == NULL) {
+		struct passwd *p = getpwuid(getuid());
+		if (p != nullptr) {
+			e = p->pw_dir;
+		}
+	}
+	if (e == nullptr) {
+		return;
+	}
+	snprintf(homedir, NAMELEN, "%s/.pwsocket", e);
+	// KONNEKT
+	struct sockaddr_un remote;
+	struct timeval tv;
+	int fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
+	if (fd == -1) {
+		perror("Cannot create unix socket");
+	   return;
+	}
+	memset(&remote, 0, sizeof(remote));
+	remote.sun_family = AF_UNIX;
+	strncpy(remote.sun_path, homedir, sizeof(remote.sun_path)-1);
+	tv.tv_sec = 2;
+	tv.tv_usec = 0;
+	setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+	setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+	if (connect(fd, (struct sockaddr*)&remote, sizeof(remote)) == -1) {
+		perror("Cannot connect to pw daemon");
+		close(fd);
+		return;
+	}
+	write(fd, "PW", 2);
+	ssize_t ret = read(fd, daemon_data, NAMELEN - 5);
+	if (ret == -1) {
+		perror("Cannot read reply from pwdaemon");
+		close(fd);
+		return;
+	}
+	if (ret == 0) {
+		fprintf(stderr, "pwdaemon is configured to not reveal pw\n");
+		close(fd);
+		return;
+	}
+	daemon_data[ret] = '\0';
+	char *ptr = daemon_data;
+	int i = strlen(creds);
+	while (++i < NAMELEN - 5) {
+		creds[i] = *ptr++;
+		if (creds[i] == '\0')
+			break;
+	}
+	creds[NAMELEN-1] = '\0';
+	close(fd);
+	::write(pfd, creds, qMin(i+1, NAMELEN));
+	::close(pfd);
+	exit(0);
+}
-- 
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