From nobody Tue Feb 10 10:20:44 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org ARC-Seal: i=1; a=rsa-sha256; t=1617825909; cv=none; d=zohomail.com; s=zohoarc; b=WQt1LyOm6UEb/c2p3ETsMSkPFZVH/xcn5IyhRcD/9C4qijEHUaW05WTNskza9gbwzjiyGFpS0gLBRysec6kfQL8vEykaYGG+1TC5I7dwYHDuqhUwM6/vVEBmaWr/Bl+/rOASnufF8wOfAYwb/us4WHMAKBIWVL3iCibl1e4v29s= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1617825909; h=Content-Type:Content-Transfer-Encoding:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=tQIJf/F3QDSi9Flx49N1VCHl+9oTTwRP0VggpER8jWQ=; b=dJOafykUnAUJZrNNhEFzdRMKkA76ha/J4FiFuOKY4mZ7xGlBljdb0L2BFpxVkZNcw+jV4QFfqQfR+2V0anQZcA4X3Jw9/FR6c8z+5NRBuWnVOrEJlK/CmzWwbzxiDgY8KFT78fjQL6ha3qsWRZDtycrQjIikRhzeJN3Lw0WYiqU= ARC-Authentication-Results: i=1; mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1617825909970999.4077374665055; Wed, 7 Apr 2021 13:05:09 -0700 (PDT) Received: from localhost ([::1]:53578 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lUEQG-0003oV-PL for importer@patchew.org; Wed, 07 Apr 2021 16:05:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51672) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUEKE-0007GQ-CA for qemu-devel@nongnu.org; Wed, 07 Apr 2021 15:58:54 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:37782 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 1lUEKC-0007Rt-Mf for qemu-devel@nongnu.org; Wed, 07 Apr 2021 15:58:54 -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 1lUEKM-00073W-Ed; Wed, 07 Apr 2021 20:59:06 +0100 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu, laurent@vivier.eu, pbonzini@redhat.com Date: Wed, 7 Apr 2021 20:57:56 +0100 Message-Id: <20210407195801.685-8-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210407195801.685-1-mark.cave-ayland@ilande.co.uk> References: <20210407195801.685-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 86.148.103.9 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH v4 for-6.0 07/12] 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 (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" If the guest tries to execute a CDB when cmdfifo is not empty before the st= art 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-Daud=C3=A9 Tested-by: Alexander Bulekov --- 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 4decbbfc29..7f49522e1d 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) =20 static void do_cmd(ESPState *s) { - uint8_t busid =3D fifo8_pop(&s->cmdfifo); + uint8_t busid =3D esp_fifo_pop(&s->cmdfifo); + int len; =20 s->cmdfifo_cdb_offset--; =20 /* Ignore extended messages for now */ if (s->cmdfifo_cdb_offset) { - esp_fifo_pop_buf(&s->cmdfifo, NULL, s->cmdfifo_cdb_offset); + len =3D MIN(s->cmdfifo_cdb_offset, fifo8_num_used(&s->cmdfifo)); + esp_fifo_pop_buf(&s->cmdfifo, NULL, len); s->cmdfifo_cdb_offset =3D 0; } =20 --=20 2.20.1