skeud

commit: ac7eca22806f1d17e66b640bcebfec06a19a6bf1
parent a6db836fe6eb640fd9a034fe379fcbe9ec5b63b4
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Mon, 10 Nov 2025 08:38:49 +0100

login: prefix shell argv0 with - instead of using -l option

This way no argument is passed to the user's login shell.

Diffstat:
M
login.c
10
+++++++++-

1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/login.c b/login.c
@@ -14,6 +14,7 @@
 
 #include <errno.h>    // errno
 #include <grp.h>      // getgrnam, initgroups
+#include <limits.h>   // NAME_MAX
 #include <pwd.h>      // getpwnam
 #include <stdbool.h>  // bool
 #include <stdio.h>    // fprintf, perror
@@ -251,9 +252,16 @@ main(int argc, char *argv[])
 
 	free(username_buf);
 
+	const char *sh_basename = strrchr(shell, '/');
+
+	sh_basename = sh_basename ? sh_basename + 1 : shell;
+
+	char shell0[NAME_MAX] = "-sh";
+	strlcpy(shell0 + 1, sh_basename, NAME_MAX - 1);
+
 	errno = 0;
 	/* flawfinder: ignore CWE-78 */
-	if(execl(shell, shell, "-l", NULL) < 0)
+	if(execl(shell, shell0, NULL) < 0)
 	{
 		if(errno == ENOENT)
 		{