skeud

commit: 2b28bce631481b27039e6952a8b1b76731ff9e37
parent 049f48f0307dd5404ec42c43f4c75b91c0b0a66d
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Thu,  3 Nov 2022 02:03:54 +0100

login: fchown current TTY to new user

Diffstat:
M
login.c
21
++++++++++++++++++++-

1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/login.c b/login.c
@@ -14,12 +14,15 @@
 
 #include <assert.h>  // assert
 #include <errno.h>   // errno
+#include <grp.h>     // getgrnam
 #include <pwd.h>     // getpwnam
 #include <stdbool.h> // bool
 #include <stdio.h>   // fprintf, perror
 #include <stdlib.h>  // abort, setenv
 #include <string.h>  // strcmp, explicit_bzero
-#include <unistd.h>  // getuid, getopt, opt*, chdir, setuid, setgid
+#include <unistd.h>  // getuid, getopt, opt*, chdir, setuid, setgid, fchown
+
+#define TTY_GROUP "tty"
 
 extern char **environ;
 char *envclear[] = {NULL};
@@ -168,6 +171,22 @@ main(int argc, char *argv[])
 
 	if(pwent != NULL)
 	{
+		int tty_gid             = pwent->pw_gid;
+		struct group *tty_group = getgrnam(TTY_GROUP);
+		if(tty_group == NULL)
+		{
+			perror("login: getgrnam");
+		}
+		else
+		{
+			tty_gid = tty_group->gr_gid;
+		}
+
+		/* considers that STDIN_FILENO is close enough to the current tty */
+		if(fchown(STDIN_FILENO, pwent->pw_uid, tty_gid) < 0)
+		{
+			perror("login: fchown");
+		}
 		if(setgid(pwent->pw_gid) < 0)
 		{
 			perror("login: setgid");