From ripley at stats.ox.ac.uk  Tue Sep 19 09:26:47 2006
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Tue, 19 Sep 2006 08:26:47 +0100 (BST)
Subject: [Rd] Using \u2030 in plot axis label -> stack smashing
In-Reply-To: <dc41e1260609182113p48a7f35dg3b27f7100f435170@mail.gmail.com>
References: <1158586738.28530.52.camel@gsimpson.geog.ucl.ac.uk>
	<loom.20060918T205234-775@post.gmane.org>
	<1158614334.2277.7.camel@graptoleberis.geog.ucl.ac.uk>
	<450F608A.30508@bfro.uni-lj.si>
	<dc41e1260609182113p48a7f35dg3b27f7100f435170@mail.gmail.com>
Message-ID: <Pine.LNX.4.64.0609190746490.27751@gannet.stats.ox.ac.uk>

I didn't have access to my FC5 boxes yesterday (electrical testing).

This does need the FC5-specific compilation options set
(-Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector
--param=ssp-buffer-size=4), so it is not surprising it is not 
reproducible elsewhere (including under valgrind, BTW).

Ei-ji's patch works (and is incorporated now), but the buffer is used at

     strncpy(s, buf, sizeof(buf) - 1); /* ensure 0-terminated */

and the 's' here should be big enough (\uxxxx can only expand to 3 bytes 
in UTF-8, so "\u2030" is four bytes in UTF-8 including the null 
terminator).  Can Ei-ji explain?

I can understand how Gavin saw this in the released FC5 RPM.  What I don't 
understand is how he saw this in 2.4.0 alpha/R-devel without setting 
non-default CFLAGS he did not tell us about.

BTW, just applying this patch will not work: you need to rebuild gram.c 
in maintainer mode.


On Tue, 19 Sep 2006, Ei-ji Nakama wrote:

> This seems to be the mine which I contrived. m(_|_)m
>
> --- R-alpha.orig/src/main/gram.y        2006-09-04 23:41:33.000000000 +0900
> +++ R-alpha/src/main/gram.y     2006-09-19 13:01:41.000000000 +0900
> @@ -99,11 +99,12 @@
> # endif
> #endif
> #include <errno.h>
> +#define MB_BUF 16
>
> static size_t ucstomb(char *s, wchar_t wc, mbstate_t *ps)
> {
>     char     tocode[128];
> -    char     buf[16];
> +    char     buf[MB_BUF];
>     void    *cd = NULL ;
>     wchar_t  wcs[2];
>     char    *inbuf = (char *) wcs;
> @@ -1709,7 +1710,7 @@
>                error(_("\\uxxxx sequences not supported"));
> #else
>                wint_t val = 0; int i, ext; size_t res;
> -               char buff[5]; Rboolean delim = FALSE;
> +               char buff[MB_BUF]; Rboolean delim = FALSE;
>                if((c = xxgetc()) == '{') delim = TRUE; else xxungetc(c);
>                for(i = 0; i < 4; i++) {
>                    c = xxgetc();
> @@ -1743,7 +1744,7 @@
> #ifdef SUPPORT_MBCS
>                else {
>                    wint_t val = 0; int i, ext; size_t res;
> -                   char buff[9]; Rboolean delim = FALSE;
> +                   char buff[MB_BUF]; Rboolean delim = FALSE;
>                    if((c = xxgetc()) == '{') delim = TRUE; else xxungetc(c);
>                    for(i = 0; i < 8; i++) {
>                        c = xxgetc();
>
>
> 2006/9/19, Gregor Gorjanc <gregor.gorjanc at bfro.uni-lj.si>:
>> Gavin Simpson wrote:
>>> On Mon, 2006-09-18 at 19:02 +0000, Gregor Gorjanc wrote:
>>>> Gavin Simpson <gavin.simpson <at> ucl.ac.uk> writes:
>>>>> Dear List
>>>>>
>>>>> I just noticed the following behaviour in R 2.3.1 Patched (2006-06-13
>>>>> r38342) and confirmed similar behaviour in R 2.4.0 alpha (2006-09-18
>>>>> r39383) & R 2.5.0 (2006-09-18 r39383) - which may actually be the same
>>>>> thing?, that trying to plot the unicode character \u2030 (which should
>>>>> be in a ?? [per mille] sign) in an axis label leads to the following
>>>>> error:
>>>>>
>>>>> *** stack smashing detected ***: /home/gavin/R/R-devel/build/bin/exec/R
>>>>> terminated
>>>>> Aborted
>>>>>
>>>>> The simplest, reproducible example I have tried is:
>>>>>
>>>>> plot(1:10, ylab = "\u2030")
>>>>>
>>>> I can not reproduce this on my Debian GNU/Linux. I get something like "S
>>>> for y label under 2.3.1 2006-06-01 and 2.5.0 2006-09-13 r39292 with the
>>>> following locale
>>>>
>>>> [1] "LC_CTYPE=en_GB.UTF-8;LC_NUMERIC=C;LC_TIME=en_GB.UTF-8;
>>>> LC_COLLATE=en_GB.UTF-8;LC_MONETARY=en_GB.UTF-8;LC_MESSAGES=en_GB.UTF-8;
>>>> LC_PAPER=C;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=C;
>>>> LC_IDENTIFICATION=C"
>>>>
>>>> It does not change if I set everything into en_GB.UTF-8. Is this valid
>>>> unicode code?
>>>>
>>>> Gregor
>>>
>>> Cheers for the follow up Gregor,
>>>
>>> I was following advice given by Prof. Ripley in a posting on R-Help
>>> about how to get the per mille character:
>>>
>>> http://finzi.psych.upenn.edu/R/Rhelp02a/archive/48709.html
>>>
>>> It should look like a "%" character but with two circles at the bottom.
>>
>> Perhaps I do not have appropriate font for this character.
>>
>> Gregor
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>
>
>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


[Rd] Using \u2030 in plot axis label -> stack smashing
Prof Brian Ripley