[Toybox] DEBUG + NORECURSE "mount" crash when not root

[enh]

actually, the NORECURSE doesn't appear to matter. just DEBUG appears
to be sufficient.

On Wed, Jan 20, 2016 at 8:27 PM, enh <enh at google.com> wrote:
> if i run "mount" as non-root, i get a crash here:
>
>     } else if (CFG_TOYBOX_DEBUG && uid && which != toy_list)
>       error_msg("Not installed suid root");
>
> because of a null pointer dereference here:
>
> void verror_msg(char *msg, int err, va_list va)
> {
>   char *s = ": %s";
>
>   fprintf(stderr, "%s: ", toys.which->name);
>
> here's the backtrace:
>
>   000000000000c7d8  verror_msg+72
> /proc/self/cwd/external/toybox/lib/lib.c:12
>   000000000000c914  error_msg+124
> /proc/self/cwd/external/toybox/lib/lib.c:27
>   000000000001011c  toy_init+88
> /proc/self/cwd/external/toybox/main.c:112
>   0000000000010318  toy_exec+180
> /proc/self/cwd/external/toybox/main.c:143
>   000000000000fec4  toybox_main+36
> /proc/self/cwd/external/toybox/main.c:156
>
> time to merge your stacktop fix and revert the NORECURSE config, but i
> thought i'd report this anyway...
>
> --
> Elliott Hughes - http://who/enh - http://jessies.org/~enh/
> Android native code/tools questions? Mail me/drop by/add me as a reviewer.



-- 
Elliott Hughes - http://who/enh - http://jessies.org/~enh/
Android native code/tools questions? Mail me/drop by/add me as a reviewer.