From owner-freebsd-net@freebsd.org Sun Apr 24 07:03:24 2016 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 72691B195CA for ; Sun, 24 Apr 2016 07:03:24 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 633D916FB for ; Sun, 24 Apr 2016 07:03:24 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id u3O73O8W079856 for ; Sun, 24 Apr 2016 07:03:24 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-net@FreeBSD.org Subject: [Bug 208985] DoS / heap overflow in bpf_stats_sysctl Date: Sun, 24 Apr 2016 07:03:24 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 11.0-CURRENT X-Bugzilla-Keywords: patch X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: cturt@hardenedbsd.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-net@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 24 Apr 2016 07:03:24 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D208985 --- Comment #3 from CTurt --- Thanks for your response. I firmly believe any `malloc` with an unchecked size from userland to absolutely be a bug. As demonstrated by my PoC code, when accessible, this = can be used to at minimum panic a system. Even when accessible to root only, ha= ving a bug like this present makes the system slightly less stable, no matter how rarely it may occur. It shouldn't really matter what requirements the function has; it is always better to fix it to eliminate the possibility of this becoming critical in = the future if the code were ever to be altered. For example, you mention having interest in altering this code in the future such that under a rare circumstance, it would be accessible with normal user privileges. My original patch set an arbitrary upper limit, which may not be appropriat= e. However, if this limit is either increased or changed to be variable, I wou= ld suggest removing the `M_WAITOK` flag and returning an error for when the ca= ll fails instead. --=20 You are receiving this mail because: You are the assignee for the bug.=