[CRIU] [PATCH cr] proc: add a static buffer to prevent segv

[Andrew Vagin]

On Wed, May 02, 2012 at 03:15:31PM +0400, Cyrill Gorcunov wrote:
> On Wed, May 02, 2012 at 02:57:25PM +0400, Andrew Vagin wrote:
> > On Wed, May 02, 2012 at 02:37:57PM +0400, Andrey Vagin wrote:
> > > A few of our functions use buffer and string functions.
> > > All these functions require that a string contains '\0' at the end.
> > > Before this patch we didn't guarantee that.
> > > 
> > > I've seen segmentation fault in parse_pid_stat_small.
> > 
> > A short version of buggy code:
> > char buf[128];
> > ret = read(fd, buf, sizeof(buf));
> > tok = strrchr(buf, ')');
> > 
> > The strrchr()  function returns a pointer to the last occurrence of the
> > character c in the string s.
> > 
> > buf should contain '\0'
> 
> Yes, strrchr is buggy here, maybe we should add
> 
> +#define read_eos(fd, buf, size)                                \
> +       ({                                                      \
> +               int r__ = read(fd, buf, size);                  \
> +               if (buf[(size) - 1])                            \
> +                       buf[(size) - 1] = '\0';                 \
> +               r__;                                            \
> +       })
> +
> 
> instead? This independent to how buf is allocated and/or it has
> EOS already. This as well makes patch simplier.

parse_maps uses a FILE object.

> 
> 	Cyrill