From 93e713929081a6bbf859adaafc9b7e5415321516 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani.haverinen@gmail.com>
Date: Sat, 8 Sep 2018 16:16:33 +0000
Subject: [PATCH] Remove execution functionality for possible security issues

---
 lewdfingerd.c | 142 +-------------------------------------------------
 1 file changed, 1 insertion(+), 141 deletions(-)

diff --git a/lewdfingerd.c b/lewdfingerd.c
index fd60f5d..d186755 100644
--- a/lewdfingerd.c
+++ b/lewdfingerd.c
@@ -146,139 +146,7 @@ ssize_t writeall_str(int fd, const char *s) {
 	return writeall(fd, s, strlen(s));
 }
 
-bool execute_finger_response(int sock, const char *finger_response_file) {
-	int pipes[2];
-	if(pipe(pipes) != 0) {
-		log_perror("pipe");
-		return false;
-	}
-
-	pid_t child = fork();
-	if(child < 0) {
-		log_perror("fork");
-		return false;
-	}
-
-	if(child == 0) {
-		// Child
-
-		// Close unneeded fds
-		for(size_t i = 0; i < num_listens; i++) {
-			close(listens[num_listens].fd);
-		}
-		close(sock);
-		close(pipes[0]);
-
-		// Set up stdout
-		if(dup2(pipes[1], STDOUT_FILENO) < 0) {
-			log_perror("dup2");
-			_exit(1);
-		}
-
-		// execv's types require this cast
-		char *argv[] = {(char*) finger_response_file, NULL};
-		execv(finger_response_file, argv);
-
-		log_perror("execv");
-		_exit(1);
-	} else {
-		// Parent
-
-		// Close unneeded fds
-		close(pipes[1]);
-
-		struct timespec start_time;
-		// Doesn't seem this could fail in our configuration
-		clock_gettime(CLOCK_MONOTONIC, &start_time);
-
-		char iobuf[1024];
-
-		struct pollfd pipe_poll = {.fd = pipes[0], .events = POLLIN};
-		for(;;) {
-			// Check the child is still running
-			int status;
-			waitpid(child, &status, WNOHANG);
-			if(WIFEXITED(status) || WIFSIGNALED(status)) {
-				// Child quit
-				if(WIFSIGNALED(status)) {
-					log_error("Child died of signal %i\n", WTERMSIG(status));
-				} else if(WIFEXITED(status) && WEXITSTATUS(status) != 0) {
-					log_error("Child exited with nonzero return code %i\n", WEXITSTATUS(status));
-				}
-				break;
-			}
-
-			struct timespec current_time;
-			// See previous usage of this
-			clock_gettime(CLOCK_MONOTONIC, &current_time);
-
-			time_t secs_passed = current_time.tv_sec - start_time.tv_sec;
-			long ns_passed = current_time.tv_nsec - start_time.tv_nsec;
-			int ms_passed = secs_passed * 1000 + ns_passed / 1000;
-			// Timeout of 5s
-			int ms_remaining = 5000 - ms_passed;
-
-			if(ms_remaining <= 0) {
-				log_error("Child ran too long\n");
-				if(kill(child, SIGKILL)) {
-					log_perror("kill");
-				}
-
-				// Wait to get rid of the zombie
-				waitpid(child, NULL, 0);
-
-				if(writeall_str(sock, "Timeout\r\n") < 0) {
-					log_perror("writeall_str");
-					close(pipes[0]);
-					return false;
-				}
-
-				break;
-			}
-
-			int amount_ready = poll(&pipe_poll, 1, ms_remaining);
-
-			for(int i = 0; i < amount_ready; i++) {
-				if(pipe_poll.revents & POLLIN) {
-					ssize_t amount_read = read(pipes[0], iobuf, sizeof(iobuf));
-					if(amount_read < 0) {
-						log_perror("read");
-						break;
-					}
-
-					char *newline_location = memchr(iobuf, '\n', amount_read);
-					if(newline_location == NULL) {
-						// No newline, write entire buffer
-						if(writeall(sock, iobuf, amount_read) < 0) {
-							log_perror("writeall");
-							break;
-						}
-					} else {
-						// Newline found. Write stuff before it and \r\n
-						if(writeall(sock, iobuf, newline_location - iobuf) < 0 || writeall_str(sock, "\r\n") < 0) {
-							log_perror("writeall / writeall_str");
-							break;
-						}
-
-						// Write the part after it
-						char *part_after_nl = newline_location + 1;
-						size_t part_after_nl_length = amount_read - (part_after_nl - iobuf);
-						if(writeall(sock, part_after_nl, part_after_nl_length) < 0) {
-							log_perror("writeall");
-							break;
-						}
-					}
-				}
-			}
-		}
-
-		close(pipes[0]);
-	}
-
-	return true;
-}
-
-bool read_finger_response(int sock, const char *finger_response_file) {
+bool handle_finger_response(int sock, const char *finger_response_file) {
 	FILE *f = fopen(finger_response_file, "r");
 	if(f == NULL) {
 		log_perror("fopen");
@@ -314,14 +182,6 @@ bool read_finger_response(int sock, const char *finger_response_file) {
 	return true;
 }
 
-bool handle_finger_response(int sock, const char *finger_response_file) {
-	if(access(finger_response_file, X_OK) == 0) {
-		return execute_finger_response(sock, finger_response_file);
-	} else {
-		return read_finger_response(sock, finger_response_file);
-	}
-}
-
 void handle_userlist(int sock, bool force_multiline) {
 	// Go over users' home dirs and see if .finger-response is present
 	bool first_line = true;