add control character sanitization

merge

.gitignore

@@ -0,0 +1 @@
+/kissy

Makefile

@@ -0,0 +1,19 @@
+CC := gcc
+CFLAGS := -O2 -pipe -Wall -Wextra
+INSTALL := install
+PREFIX := /usr/local
+BINDIR := bin
+
+.PHONY: all
+all: kissy
+
+kissy: kissy.c
+	$(CC) $(CFLAGS) -o kissy kissy.c
+
+.PHONY: install
+install:
+	$(INSTALL) -Dm2755 -oroot -gtty -s kissy $(DESTDIR)$(PREFIX)/$(BINDIR)/kissy
+
+.PHONY: clean
+clean:
+	rm -f kissy

README.md

@@ -4,9 +4,11 @@ Ever wanted to kiss girls through a tty? Well now you can!
 
 ### Installation:
 - download kissy from the releases page and place it in the system's path
-- run `sudo chown :tty /path/to/kissy` (or whatever group it's supposed to be)
+- run `sudo chown root:tty /path/to/kissy` (or whatever ownership it's supposed to have)
 - run `sudo chmod 2755 /path/to/kissy` (or whatever permissions work for you. has to run with setgid)
 
+- alternatively, build kissy from source using `make` then `sudo make install`
+
 ### Usage:
 `kissy [target] <message>`
 

kissy.c

@@ -1,4 +1,4 @@
-// KISSY (Kissing Interface for Sapphic Smooching over ttY) v1.0
+// KISSY (Kissing Interface for Sapphic Smooching over ttY) v1.2
 
 /*
     Copyright (C) 2025  Magdalunaa <magdalunaa@linuxposting.xyz>
@@ -17,17 +17,6 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-/*
-This file needs to:
-- be owned by the tty group (or whatever group owns the terminal devices in your system)
-- have setgid set
-- be group executable
-- not be world writeable
-
-You can probably just use 2755 permissions. those work
-
-*/
-
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
@@ -35,32 +24,37 @@ You can probably just use 2755 permissions. those work
 #include <dirent.h>
 #include <string.h>
 #include <pwd.h>
+#include <stdbool.h>
+#include <ctype.h>
 
 // mreowww meow nya :3
 
 int main (int argc, char **argv) {
+
+    // print help
+    if (argc < 2 || strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-h") == 0) {
+        printf("%s\n", "Usage: kissy [target] <message>\n\n"
+            "Kissy is a utility that allows you to kiss currently logged in users who allow messages.\n"
+            "It works by writing to files in /dev/pts. It needs to run as the group who owns said files (usually tty), using setgid (2755 permissions).");
+        return 0;
+    }
+
     // are we running with setgid?
     struct stat stat_self;
     stat("/proc/self/exe", &stat_self);
 
     if (!(stat_self.st_mode & S_ISGID && !(stat_self.st_mode & S_IWOTH))) {
-        printf("%s\n", "setgid is not set, or this file is world writeable.");
+        printf("%s\n", "setgid is not set, or this file is world writable.");
         return 3;
     }
 
-    // check we have at least one argument
-    if (argc < 2) {
-        printf("%s\n", "Not enough arguments!\nUsage: kissy [target] <message>");
-        return 0;
-    }
-
     // try to find the target's uid
     struct passwd *pw = getpwnam(argv[1]);
     if (pw == NULL) {
         printf("%s\n", "Cannot find target");
         return 1;
     }
-    int target = pw->pw_uid;
+    uid_t target = pw->pw_uid;
 
     // get current username
     struct passwd *pw2 = getpwuid(getuid());
@@ -71,13 +65,22 @@ int main (int argc, char **argv) {
     char* user = pw2->pw_name;
 
     // if we have a second argument, set a custom kiss message
-    char* kiss;
+    char kiss[32] = "*mwah*";
-    if (argc >= 3)
+    if (argc >= 3) {
-        kiss = argv[2];
+        int len = strlen(argv[2]);
-    else
+        int written_chars = 0;
-        kiss = "*mwah*";
+        for (int i = 0; i < len; i++) {
+            if (written_chars >= 31) {
+                kiss[31] = '\0';
+                break;
+            };
+            if (iscntrl(argv[2][i])) continue;
+            kiss[i] = argv[2][i];
+            written_chars++;
+        }
+    }
     
-    short kissed = 0;
+    bool kissed = false;
     // iterate over all files in directory
     DIR *dir = opendir("/dev/pts");
     while (1) {
@@ -94,13 +97,13 @@ int main (int argc, char **argv) {
 
         // find all terminals with the correct user and that are group-writable
         if (stats.st_mode & S_IWGRP && stats.st_uid == target) {
-            kissed = 1;
+            kissed = true;
 
             if (stats.st_gid != getegid()) { // are we running as the tty user?
-                printf("%s\n", "Mismatch between file owner group and current effective group. Make sure this program is running with setgid.");
+                fprintf(stderr, "%s\n", "Mismatch between file owner group and current effective group. Make sure this program is running with setgid.");
             } else {
                 FILE *tty = fopen(filepath, "a"); // write to terminal!
-                fprintf(tty, "\n%s\n--%s\n", kiss, user);
+                fprintf(tty, "\a\n%s\n--%s\n", kiss, user);
                 fclose(tty);
             }
         }
@@ -108,5 +111,5 @@ int main (int argc, char **argv) {
 
     // print a message if a suitable terminal couldn't be found
     if (!kissed)
-            printf("%s\n", "Couldn't find any suitable terminals. User is not logged in or has not enabled messages.");
+        fprintf(stderr, "%s\n", "Couldn't find any suitable terminals. User is not logged in or has not enabled messages.");    
 }