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

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Date:	Fri, 21 Sep 2007 03:56:47 +0200
From:	"Arvin Moezzi" <moezzia@...il.com>
To:	"James Pearson" <james-p@...ing-picture.com>,
	linux-kernel@...r.kernel.org
Cc:	aarapov@...hat.com, akpm@...ux-foundation.org, hpa@...or.com
Subject: Re: [PATCH -mm] Don't truncate /proc/PID/environ at 4096 characters

2007/9/19, James Pearson <james-p@...ing-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?

Arvin
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