[LTP] mount01.c issue

[Giese, B. <Bru...@an...>]

In mount01.c:

This looks like a bug in the test case. In the code snippet below:

	if (Tflag) {
		Fstype =3D (char *) malloc(strlen(fstype));
                                  ^^^^^^^^^^^^^^^
                              malloc(strlen(fstype) + 1)
WOULD
BE CORRECT
		if(Fstype =3D=3D NULL) {
			tst_brkm(TBROK, NULL, "malloc - failed to alloc
%d"
				 "errno %d", strlen(fstype), errno);
		}
		strncpy(Fstype, fstype, strlen(fstype));
                                    ^^^^^^^^^^^^^
						strlen(fstype) + 1
WOULD BE CORRECT
	} else {
		Fstype =3D (char *) malloc(strlen(DEFAULT_FSTYPE));
                                  ^^^^^^^^^^^^^^^
                              malloc(strlen(DEFAULT_FSTYPE) + 1)
WOULD
BE CORRECT
		if(Fstype =3D=3D NULL) {
			tst_brkm(TBROK, NULL, "malloc - failed to alloc
%d"
				 "errno %d", strlen(DEFAULT_FSTYPE),
errno);
		}
		strncpy(Fstype, DEFAULT_FSTYPE, strlen(DEFAULT_FSTYPE));
                                           ^^^^^^^^^^^^^^^^^^
=09
strlen(DEFAULT_FSTYPE) + 1 WOULD BE CORRECT
	}


In either case (Tflag or not), one less byte is being allocated (the
space for '\0') and one less byte is being copied.

The variable Fstype is subsequently used in the mount call that expects
a const char *, which I presume has to be '\0 terminated - the mount
documentation (man 2
mount) does
not say anything otherwise.

Looking at the sys_mount code in linux-2.6.x/fs directory, there is a
path that leads to a strcpy, which would require a trailing '\0'.

(sys_mount
	do_mount
		do_kern_mount
			get_fs_type
				strcpy)

Bruce Giese (relaying what was said by one of our contractors in India)