Re: [PATCH] sysctl: terminate strings also on \r

From: Andrew Morton
Date: Wed Oct 22 2014 - 19:26:43 EST


On Tue, 21 Oct 2014 13:21:37 -0700 Kees Cook <keescook@xxxxxxxxxxxx> wrote:

> From: Paul Wise <pabs3@xxxxxxxxxxxxx>
>
> This partially mitigates a common strategy used by attackers for hiding
> the full contents of strings in procfs from naive sysadmins who use cat,
> more or sysctl to inspect the contents of strings in procfs.
>
> ...
>
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -1739,7 +1739,7 @@ static int _proc_do_string(char *data, int maxlen, int write,
> while ((p - buffer) < *lenp && len < maxlen - 1) {
> if (get_user(c, p++))
> return -EFAULT;
> - if (c == 0 || c == '\n')
> + if (c == 0 || c == '\n' || c == '\r')
> break;
> data[len++] = c;
> }

There are no valid uses of \r in a procfs write?
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