v4.19.13 snapshot.
diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c
new file mode 100644
index 0000000..7cde3f4
--- /dev/null
+++ b/fs/binfmt_script.c
@@ -0,0 +1,130 @@
+/*
+ * linux/fs/binfmt_script.c
+ *
+ * Copyright (C) 1996 Martin von Löwis
+ * original #!-checking implemented by tytso.
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/binfmts.h>
+#include <linux/init.h>
+#include <linux/file.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+
+static int load_script(struct linux_binprm *bprm)
+{
+ const char *i_arg, *i_name;
+ char *cp;
+ struct file *file;
+ int retval;
+
+ if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
+ return -ENOEXEC;
+
+ /*
+ * If the script filename will be inaccessible after exec, typically
+ * because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give
+ * up now (on the assumption that the interpreter will want to load
+ * this file).
+ */
+ if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
+ return -ENOENT;
+
+ /*
+ * This section does the #! interpretation.
+ * Sorta complicated, but hopefully it will work. -TYT
+ */
+
+ allow_write_access(bprm->file);
+ fput(bprm->file);
+ bprm->file = NULL;
+
+ bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
+ if ((cp = strchr(bprm->buf, '\n')) == NULL)
+ cp = bprm->buf+BINPRM_BUF_SIZE-1;
+ *cp = '\0';
+ while (cp > bprm->buf) {
+ cp--;
+ if ((*cp == ' ') || (*cp == '\t'))
+ *cp = '\0';
+ else
+ break;
+ }
+ for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++);
+ if (*cp == '\0')
+ return -ENOEXEC; /* No interpreter name found */
+ i_name = cp;
+ i_arg = NULL;
+ for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++)
+ /* nothing */ ;
+ while ((*cp == ' ') || (*cp == '\t'))
+ *cp++ = '\0';
+ if (*cp)
+ i_arg = cp;
+ /*
+ * OK, we've parsed out the interpreter name and
+ * (optional) argument.
+ * Splice in (1) the interpreter's name for argv[0]
+ * (2) (optional) argument to interpreter
+ * (3) filename of shell script (replace argv[0])
+ *
+ * This is done in reverse order, because of how the
+ * user environment and arguments are stored.
+ */
+ retval = remove_arg_zero(bprm);
+ if (retval)
+ return retval;
+ retval = copy_strings_kernel(1, &bprm->interp, bprm);
+ if (retval < 0)
+ return retval;
+ bprm->argc++;
+ if (i_arg) {
+ retval = copy_strings_kernel(1, &i_arg, bprm);
+ if (retval < 0)
+ return retval;
+ bprm->argc++;
+ }
+ retval = copy_strings_kernel(1, &i_name, bprm);
+ if (retval)
+ return retval;
+ bprm->argc++;
+ retval = bprm_change_interp(i_name, bprm);
+ if (retval < 0)
+ return retval;
+
+ /*
+ * OK, now restart the process with the interpreter's dentry.
+ */
+ file = open_exec(i_name);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+
+ bprm->file = file;
+ retval = prepare_binprm(bprm);
+ if (retval < 0)
+ return retval;
+ return search_binary_handler(bprm);
+}
+
+static struct linux_binfmt script_format = {
+ .module = THIS_MODULE,
+ .load_binary = load_script,
+};
+
+static int __init init_script_binfmt(void)
+{
+ register_binfmt(&script_format);
+ return 0;
+}
+
+static void __exit exit_script_binfmt(void)
+{
+ unregister_binfmt(&script_format);
+}
+
+core_initcall(init_script_binfmt);
+module_exit(exit_script_binfmt);
+MODULE_LICENSE("GPL");