Re: [PATCH v2 2/3] Introduce a function to run regexec() on non-NUL-terminated buffers

> On Thu, Sep 08, 2016 at 09:31:11AM +0200, Johannes Schindelin wrote:
> 
> > diff --git a/git-compat-util.h b/git-compat-util.h
> > index db89ba7..19128b3 100644
> > --- a/git-compat-util.h
> > +++ b/git-compat-util.h
> > @@ -965,6 +965,27 @@ void git_qsort(void *base, size_t nmemb, size_t size,
> >  #define qsort git_qsort
> >  #endif
> >  
> > +static inline int regexec_buf(const regex_t *preg, const char *buf, size_t size,
> > +			      size_t nmatch, regmatch_t pmatch[], int eflags)
> > +{
> > +#ifdef REG_STARTEND
> > +	assert(nmatch > 0 && pmatch);
> > +	pmatch[0].rm_so = 0;
> > +	pmatch[0].rm_eo = size;
> > +	return regexec(preg, buf, nmatch, pmatch, eflags | REG_STARTEND);
> > +#else
> > +	char *buf2 = xmalloc(size + 1);
> > +	int ret;
> > +
> > +	memcpy(buf2, buf, size);
> > +	buf2[size] = '\0';
> 
> I mentioned elsewhere that I'd prefer we just push people into using
> compat/regex if they don't have REG_STARTEND. But if we _do_ keep this
> fallback, note that the above has a buffer overflow (think what happens
> when "size" is the maximum value for a size_t).  You can avoid it by
> using xmallocz().