Re: [PATCH -mm] Don't truncate /proc/PID/environ at 4096 characters

[James Pearson <james-p@moving-picture.com>]

Arvin Moezzi wrote:
> 2007/9/19, James Pearson <james-p@moving-picture.com>:
>
> > +       while (count > 0) {
> > +               int this_len, retval;
> > +
> > +               this_len = mm->env_end - (mm->env_start + src);
> > +
> > +               if (this_len <= 0)
> > +                       break;
> > +
> > +               if (this_len > max_len)
> > +                       this_len = max_len;
> > +
> > +               retval = access_process_vm(task, (mm->env_start + src),
> > +                       page, this_len, 0);
> > +
> > +               if (retval <= 0) {
> > +                       ret = retval;
> > +                       break;
> > +               }
> > +
> > +               if (copy_to_user(buf, page, retval)) {
>
>                                                                 ^^^^
> shouldn't you only copy min(count,retval) bytes? otherwise you could
> write beyond the users buffer "buf", right?

AFAIK, 'retval' can never be greater than 'this_len', which can never be 
greater than 'max_len', which can never be greater than 'count'

James Pearson
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