[BusyBox] patch to login, dmesg and obscure

[Ronny L Nilsson]

> > * libbb/obscure.c:password_check()
> > There was a buffer overflow bug which cased passwd command to
> > segfault when invoked by any other than the superuser.
>
> from libbb/obscure.c:password_check()
>          newmono = str_lower(bb_xstrdup(newval));
>          lenwrap = strlen(old) * 2 + 1;
>          wrapped = (char *) xmalloc(lenwrap);
> wrapped have size(old) * 2 +1. This can`t overflow for rotate check.
>


Are you realy sure?? Becuse some lines down ther's a
	strcat(wrapped, wrapped)
instruction where the actual overflow occure.

This is an excerpt from STRCAT(3) manpage:
DESCRIPTION
	The strcat() function appends the src string to
	the dest string over writing the `\0' character at
	the end of dest, and then adds a terminating
	`\0'  character. The strings may not overlap,
	and the dest string must have enough space for
	the result.
Which clearly says the used behaviour is illegal.




> > * util-linux/dmesg.c:
> But,  CONFIG_FEATURE_CLEAN_UP is very not require.
>
> You must add
> #ifdef CONFIG_FEATURE_CLEAN_UP
>   = NULL;
> #endif
> To your patch.


ok, I'll fix it.


/Ronny