[Fedora 12/19] ptrace: Do not allow ptrace() from unsigned process to signed one

[Matthew Garrett]

On Wed, 2013-09-04 at 17:24 -0400, Vivek Goyal wrote:

Doesn't this:

> +		if (!ptraced_by_unsafe_tracer())
> +			bprm->cred->proc_signed = true;

race with this if the attacker is able to run between the check and
proc_signed being set to true?

> +	if (mode != PTRACE_MODE_READ && child_cred->proc_signed &&
> +	    !cred->proc_signed) {
> +		ret = -EPERM;
> +		goto out;
> +	}


-- 
Matthew Garrett <matthew.garrett at nebula.com>