From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F3853CEBBD; Tue, 16 Jun 2026 18:14:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781633699; cv=none; b=gvA5+NOumafGBtLvC97R9wa5ha6/prre2WPiqsDc2nFTr5fMkrYnGttjIFTvnCtRfG4hxjjk0TUjhxlNk0XCzOJa5Pefk8Og+1b/B9EXSFqW2U3XMxMik+QcXHz3Vx0abm0CVQT+LJlNJlEePS8lN6cVCzztiz9XhPJwUtzl8DQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781633699; c=relaxed/simple; bh=biLggEn2GhmXPBxNLWXQj/6zpQTwfuYnHXCxGkFeQns=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uykNVNdxn/5Ul4tWDhai57P8J4t20Te4O2YLI4tjKzN5F6Zg+JxWrsCRy7joUkqsGQhGeqVXGifBVvL8aecYqfd44Kuz85MCVohcGV/l80VBrzKrwxGkukhvHB3S/WSjM7YOKVzUWJ5iPrVli1JeqGSACI8zfuhThUwdsk0KRjg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bpp/s8hY; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bpp/s8hY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 624511F000E9; Tue, 16 Jun 2026 18:14:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781633698; bh=Bp+jGTSi7WwnsakLN7+68jyKG8ZIh+xNUAZm3r66X78=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bpp/s8hYSSmiCPwgRQvmJpZ6NVesUc+dhkNHmUkr9feI+ynclEiHN+wKtAGeUJls5 CJa4HVaJYp5j3/T+ECwX0B4EMHe4HvIIyc5ee7/VXICKm2EftRKZVTqwgoWUDsPTAa r4mysIiu1eosaRQrsFeNgZ/pH6L8ErfDieFRas/c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yuhao Jiang , Junrui Luo , Jakub Kicinski Subject: [PATCH 5.15 085/411] macsec: fix replay protection at XPN lower-PN wrap Date: Tue, 16 Jun 2026 20:25:23 +0530 Message-ID: <20260616145104.770269951@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145100.376842714@linuxfoundation.org> References: <20260616145100.376842714@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Junrui Luo commit e68842b3356471ba56c882209f324613dac47f64 upstream. In macsec_post_decrypt(), when pn is U32_MAX, pn + 1 overflows u32 to 0 and the first branch never fires. If next_pn_halves.lower is also in the upper half, pn_same_half(pn, lower) is true and the XPN else-if does not fire either, leaving next_pn_halves unchanged. An attacker that captures the legitimate frame carrying pn == 0xFFFFFFFF on an XPN association can then replay it indefinitely, since lowest_pn never rises above the captured pn and macsec_decrypt() reconstructs the same IV. Extend the XPN else-if to also fire when pn + 1 wraps to 0, so receipt of pn == U32_MAX advances next_pn_halves to (upper + 1, 0). Fixes: a21ecf0e0338 ("macsec: Support XPN frame handling - IEEE 802.1AEbw") Reported-by: Yuhao Jiang Cc: stable@vger.kernel.org Signed-off-by: Junrui Luo Link: https://patch.msgid.link/SYBPR01MB78813FD49E58F253B989F197AF012@SYBPR01MB7881.ausprd01.prod.outlook.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/macsec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -824,7 +824,8 @@ static bool macsec_post_decrypt(struct s if (pn + 1 > rx_sa->next_pn_halves.lower) { rx_sa->next_pn_halves.lower = pn + 1; } else if (secy->xpn && - !pn_same_half(pn, rx_sa->next_pn_halves.lower)) { + (pn + 1 == 0 || + !pn_same_half(pn, rx_sa->next_pn_halves.lower))) { rx_sa->next_pn_halves.upper++; rx_sa->next_pn_halves.lower = pn + 1; }