From nobody Mon Apr 11 18:15:46 2022 X-Original-To: bugs@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id AA5BE11CF506 for ; Mon, 11 Apr 2022 18:15:46 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4KccVB2Xprz4y8C for ; Mon, 11 Apr 2022 18:15:46 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 3394E27C9E for ; Mon, 11 Apr 2022 18:15:46 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 23BIFkke004681 for ; Mon, 11 Apr 2022 18:15:46 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 23BIFkaQ004680 for bugs@FreeBSD.org; Mon, 11 Apr 2022 18:15:46 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 263226] carp does not include carp_advskew or carp_advbase in HMAC Date: Mon, 11 Apr 2022 18:15:46 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: emaste@freebsd.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Bug reports List-Archive: https://lists.freebsd.org/archives/freebsd-bugs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-bugs@freebsd.org MIME-Version: 1.0 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1649700946; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=TFxFcsTvJBOLatsBVQBqYHBo+Qah34HWxo8YRJBli38=; b=rY8NF7R+B8Ctwdfhmi2JoseYTF8xkUg7shb7L+w3Cze7rCHVwRr3Lz5xyJpYDw8e4BgO4G 5lD8UJaXSVv6dtlztEQMQNjBGF4EAfH+HJSui0dUu7bU+8yrGvUQ1fSoiGOAeGJyh9ifbL LITLMGrg5MjWIRRK4nFWHb9RFvsukDUeivcvxg3+crEE4vdfVjsLckHGci+cxUwtKN9dV/ sZdAg8v5BWec/yV/Uw+kqtnS8v9X36oYcFMd6DTHBjeaYxKB7yCFqz/690uWID6NBwj0RA u8Sqtkbv7O5OLHL4kfWo3hzHdLumUClaOzjG1HoKEybQENQUs1eKtJds07TZ7w== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1649700946; a=rsa-sha256; cv=none; b=myDDvusWpGNdhs+Qz3IBg6FZlPAiJ5pi+QK7dPt2ydFAI0d4pUT5n36emCP1TrzuOSvwfV QBnMltKTnqdTjGg1F4kQ6GAoS/M+IyBEke9SqdoYTdyk2MYnH1atsvU9zU5m5fuOD2J2NQ GHeBRKmeqkoLlnbxnVax3wYW+5NP2KIqz5zPBMiLCOsXTLRYPFH7hW9Aj3b36hyHFBR3Qx v3yxtcNATuiwzfIDQCXCxzEUhae50Y6qts++gl6DbIorSZw48LRMTrEBvTq3zHQ9w07/Z7 PGH9sFXGRWzLj+3WNUV6g0Y9fb1rsNu8Y5/C5fxpBqvWuLKjYAN77ynvcUJTIw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D263226 Bug ID: 263226 Summary: carp does not include carp_advskew or carp_advbase in HMAC Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: emaste@freebsd.org Issue reported on the fulldisclosure list in 2010 https://seclists.org/fulldisclosure/2010/Dec/489 The OpenBSD CARP implementation (and all derivatives, such as FreeBSD and NetBSD) fails to include all fields contained in the "carp_header" structure[1] when calculating the SHA1 HMAC hash of the packet in the function carp_proto_input_c[2]. The two 8-bit fields not included in the hash generation are "carp_advskew" and "carp_advbase". Among other functions, the fields are both set to 255 by the master CARP node to indicate that it wants to step down from the master role. This behaviour can be exploited to force a backup member to assume the role of master by capturing a master CARP advertisement, updating the two fields in question to 255 and replaying the modified packet. A backup node will receive this packet and the hash check will be satisfied as the two modified fields are not included in the hash generation. A backup node will now assume the master role and the current master will step down to backup. At this point, the attacker can now capture an advertisement from the new master. By replaying both of the unmodified master advertisements, all CARP nodes assume the backup role. At this point, a Denial of Service (DoS) condition has been introduced as no device answers ARP requests for the Virtual IP (VIP). The attacker can now decide whether to start answering ARP for the VIP therefore performing a Man in the Middle (MitM) attack. --=20 You are receiving this mail because: You are the assignee for the bug.=