From patchwork Mon Apr 12 22:20:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Mark Cave-Ayland X-Patchwork-Id: 1465491 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4FK3VG2rd8z9sW8 for ; Tue, 13 Apr 2021 08:35:50 +1000 (AEST) Received: from localhost ([::1]:34746 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lW59n-0003u4-EB for incoming@patchwork.ozlabs.org; Mon, 12 Apr 2021 18:35:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38610) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lW4wE-00036y-RD for qemu-devel@nongnu.org; Mon, 12 Apr 2021 18:21:48 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:44088 helo=mail.default.ilande.uk0.bigv.io) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lW4wA-0002yL-IL for qemu-devel@nongnu.org; Mon, 12 Apr 2021 18:21:46 -0400 Received: from host86-148-103-9.range86-148.btcentralplus.com ([86.148.103.9] helo=kentang.home) by mail.default.ilande.uk0.bigv.io with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lW4wI-0004Dc-TM; Mon, 12 Apr 2021 23:21:57 +0100 From: Mark Cave-Ayland To: peter.maydell@linaro.org, qemu-devel@nongnu.org Date: Mon, 12 Apr 2021 23:20:43 +0100 Message-Id: <20210412222048.22818-9-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210412222048.22818-1-mark.cave-ayland@ilande.co.uk> References: <20210412222048.22818-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 86.148.103.9 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PULL 08/13] esp: don't underflow cmdfifo in do_cmd() X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.default.ilande.uk0.bigv.io) Received-SPF: pass client-ip=2001:41c9:1:41f::167; envelope-from=mark.cave-ayland@ilande.co.uk; helo=mail.default.ilande.uk0.bigv.io X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" If the guest tries to execute a CDB when cmdfifo is not empty before the start of the message out phase then clearing the message out phase data will cause cmdfifo to underflow due to cmdfifo_cdb_offset being larger than the amount of data within. Since this can only occur by issuing deliberately incorrect instruction sequences, ensure that the maximum length of esp_fifo_pop_buf() is limited to the size of the data within cmdfifo. Buglink: https://bugs.launchpad.net/qemu/+bug/1909247 Signed-off-by: Mark Cave-Ayland Reviewed-by: Philippe Mathieu-Daudé Tested-by: Alexander Bulekov Message-Id: <20210407195801.685-8-mark.cave-ayland@ilande.co.uk> --- hw/scsi/esp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 904fa3179c..d3b105b703 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -319,13 +319,15 @@ static void do_busid_cmd(ESPState *s, uint8_t busid) static void do_cmd(ESPState *s) { - uint8_t busid = fifo8_pop(&s->cmdfifo); + uint8_t busid = esp_fifo_pop(&s->cmdfifo); + int len; s->cmdfifo_cdb_offset--; /* Ignore extended messages for now */ if (s->cmdfifo_cdb_offset) { - esp_fifo_pop_buf(&s->cmdfifo, NULL, s->cmdfifo_cdb_offset); + len = MIN(s->cmdfifo_cdb_offset, fifo8_num_used(&s->cmdfifo)); + esp_fifo_pop_buf(&s->cmdfifo, NULL, len); s->cmdfifo_cdb_offset = 0; }