From nobody Wed Nov 19 12:34:07 2025 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=1615937582; cv=none; d=zohomail.com; s=zohoarc; b=mi7b78dSuhKsdp4uZHH6vX0OxI9+2yJfUVkCZRI88MEGEWY4MYCQns1grP5sPAFqNmw8gpRR/BFrfByoHHxkwIzrsnybBmzntp3q8ZfHghAhHSJxAeG15hp7IUxp78fnOltrKAOMsmfYDLuo5OJUfc8cm8Tf08yP3kN4EEwSqLU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1615937582; h=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=OP0k54yqbjanqGf/yorgE+TGQ4bMmrkAczmTe2Q7EMs=; b=E0yy1O8XGRR7qfEYz75tolr+jbVVN/qUkCUJ4VtkzhIRty5wzoFAJtzr/fDsC7UpABjiKQEeye8kRZHqK+e8eC37scuD9pa6QHTJzP0za8WWe2s168YUYRExNhS2KVkcogwpBepTyhDMIos/1NbGDfyxrY1G7eeHecjeaezndn4= 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 1615937582795649.3426948712016; Tue, 16 Mar 2021 16:33:02 -0700 (PDT) Received: from localhost ([::1]:50772 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMJBN-0003dw-N9 for importer@patchew.org; Tue, 16 Mar 2021 19:33:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59736) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMJ9T-0002LM-PW for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:03 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:33370 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 1lMJ9S-0007EJ-8F for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:03 -0400 Received: from host109-156-104-46.range109-156.btcentralplus.com ([109.156.104.46] 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 1lMJ9P-0006Mg-5X; Tue, 16 Mar 2021 23:31:05 +0000 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu Date: Tue, 16 Mar 2021 23:30:21 +0000 Message-Id: <20210316233024.13560-2-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> References: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 109.156.104.46 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH 1/4] esp: don't underflow cmdfifo if no message out/command data is present 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" Content-Type: text/plain; charset="utf-8" If a guest sends a TI (Transfer Information) command without previously sen= ding any message out/command phase data then cmdfifo will underflow triggering an assert reading the IDENTIFY byte. Buglink: https://bugs.launchpad.net/qemu/+bug/1919035 Signed-off-by: Mark Cave-Ayland Tested-by: Alexander Bulekov --- hw/scsi/esp.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 507ab363bc..5d3f1ccbc8 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -318,18 +318,24 @@ 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; uint32_t n; =20 - s->cmdfifo_cdb_offset--; + if (fifo8_num_used(&s->cmdfifo)) { + busid =3D fifo8_pop(&s->cmdfifo); =20 - /* Ignore extended messages for now */ - if (s->cmdfifo_cdb_offset) { - fifo8_pop_buf(&s->cmdfifo, s->cmdfifo_cdb_offset, &n); - s->cmdfifo_cdb_offset =3D 0; - } + if (s->cmdfifo_cdb_offset) { + s->cmdfifo_cdb_offset--; + + /* Ignore extended messages for now */ + if (s->cmdfifo_cdb_offset) { + fifo8_pop_buf(&s->cmdfifo, s->cmdfifo_cdb_offset, &n); + s->cmdfifo_cdb_offset =3D 0; + } + } =20 - do_busid_cmd(s, busid); + do_busid_cmd(s, busid); + } } =20 static void satn_pdma_cb(ESPState *s) --=20 2.20.1 From nobody Wed Nov 19 12:34:07 2025 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=1615937688; cv=none; d=zohomail.com; s=zohoarc; b=DX+7z5m5hAWLsQFDjiZWKdTKKJJ2KZxaCBu/qCDIprMQy1ME2tKuSUzJ6yAYPuFuaFLUOwplBce9L0SxDM9g6gE8pBHKIuhuKo1E1guqPBXns43ZTGvL8y3WSR9YBDgidMUQtaMC1bCYbs9kvz75Ird/qP37oxrnzmoTKNNehEw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1615937688; h=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=y0j0BLkio8Vvw+yjHqtE1l/kbz/AP8BsnhpX7IzOeyQ=; b=SrBtnYzeFrspU9IJ0dil0RpCFe41OFSnu7PFaE2Kdj9TSvJ6j6UcC6PvIKvxrJcv143r3GsITzbvrVho2LAKY1JD26D2AT3vb6wyIrAPI2DEZ34wuTBVIAx6TLM98ZDZHiOQ4xdSDqo2H6ytt6pt3dTo8oJ1ds2Ra3OcKzrcbIA= 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 1615937688100321.94531285265987; Tue, 16 Mar 2021 16:34:48 -0700 (PDT) Received: from localhost ([::1]:57058 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMJD4-0006Fb-Vw for importer@patchew.org; Tue, 16 Mar 2021 19:34:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59792) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMJ9Z-0002Tp-JS for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:09 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:33376 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 1lMJ9X-0007GH-Id for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:09 -0400 Received: from host109-156-104-46.range109-156.btcentralplus.com ([109.156.104.46] 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 1lMJ9V-0006Mg-EF; Tue, 16 Mar 2021 23:31:10 +0000 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu Date: Tue, 16 Mar 2021 23:30:22 +0000 Message-Id: <20210316233024.13560-3-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> References: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 109.156.104.46 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH 2/4] esp: don't overflow cmdfifo if TC is larger than the cmdfifo size 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" Content-Type: text/plain; charset="utf-8" If a guest transfers the message out/command phase data using DMA with a TC that is larger than the cmdfifo size then the cmdfifo overflows triggering an assert. Limit the size of the transfer to the free space available in cmdfifo. Buglink: https://bugs.launchpad.net/qemu/+bug/1919036 Signed-off-by: Mark Cave-Ayland Reviewed-by: Philippe Mathieu-Daud=C3=A9 Tested-by: Alexander Bulekov --- hw/scsi/esp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 5d3f1ccbc8..bbcbfa4a91 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -579,6 +579,7 @@ static void esp_do_dma(ESPState *s) cmdlen =3D fifo8_num_used(&s->cmdfifo); trace_esp_do_dma(cmdlen, len); if (s->dma_memory_read) { + len =3D MIN(len, fifo8_num_free(&s->cmdfifo)); s->dma_memory_read(s->dma_opaque, buf, len); fifo8_push_all(&s->cmdfifo, buf, len); } else { --=20 2.20.1 From nobody Wed Nov 19 12:34:07 2025 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=1615937790; cv=none; d=zohomail.com; s=zohoarc; b=kLINlUkjzsQZjI5kFeEJpG+U9TSkF58H7x4R+DurYEIS4rDLIgyvNK1pRtXVpnrKd6xtsrMgh3j6EV6G43hA5sHz4tlvdhFFi1O7TSOi9sktFLlhtgFmHGq15eCcRqZUIz6cqYZaUUuDoYj/4gSXc69wPI3swqZsQ/WUz/XPXpw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1615937790; h=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=ORb6Wa9Fa/vmJpLe9u1b/EKYUfbTufb+41PJnlG2u5U=; b=iGyUSA2IHvk+0sgLVwtQv5wH8qXdfCRnHB7yD2nmX8Y/Hplzja+2+u0OIEsHWPFm+lPESIxqQX97+GpkxvzozqQMmo7xjcaxP2XrYrWCNlBgTqh2MAyjyawgoFGGuDrK/QiJeMh/2FW44FffzmdNWVPC6ESobw9H+qbo1d7qljk= 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 1615937790670468.48485470673165; Tue, 16 Mar 2021 16:36:30 -0700 (PDT) Received: from localhost ([::1]:35062 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMJEf-0000R4-VC for importer@patchew.org; Tue, 16 Mar 2021 19:36:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59816) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMJ9e-0002aM-Rw for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:15 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:33382 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 1lMJ9d-0007Ic-0j for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:14 -0400 Received: from host109-156-104-46.range109-156.btcentralplus.com ([109.156.104.46] 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 1lMJ9a-0006Mg-SC; Tue, 16 Mar 2021 23:31:16 +0000 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu Date: Tue, 16 Mar 2021 23:30:23 +0000 Message-Id: <20210316233024.13560-4-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> References: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 109.156.104.46 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH 3/4] esp: ensure cmdfifo is not empty and current_dev is non-NULL 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" Content-Type: text/plain; charset="utf-8" When about to execute a SCSI command, ensure that cmdfifo is not empty and current_dev is non-NULL. This can happen if the guest tries to execute a TI (Transfer Information) command without issuing one of the select commands first. Buglink: https://bugs.launchpad.net/qemu/+bug/1910723 Buglink: https://bugs.launchpad.net/qemu/+bug/1909247 Signed-off-by: Mark Cave-Ayland Reviewed-by: Philippe Mathieu-Daud=C3=A9 --- hw/scsi/esp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index bbcbfa4a91..ae362c9dfb 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -286,6 +286,9 @@ static void do_busid_cmd(ESPState *s, uint8_t busid) trace_esp_do_busid_cmd(busid); lun =3D busid & 7; cmdlen =3D fifo8_num_used(&s->cmdfifo); + if (!cmdlen || !s->current_dev) { + return; + } buf =3D (uint8_t *)fifo8_pop_buf(&s->cmdfifo, cmdlen, &n); =20 current_lun =3D scsi_device_find(&s->bus, 0, s->current_dev->id, lun); --=20 2.20.1 From nobody Wed Nov 19 12:34:07 2025 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=1615937639; cv=none; d=zohomail.com; s=zohoarc; b=luTvdjut6bRHZWUADpd3aIjNt3g0TfVXDQcyU8raWoFADDNbfvWeXURfmsM2cb8Y3V8TQsQCmPCm8BtY/hPtWa55iClvQOaSPZ5uC0wTPTgQqVQroEkgfZiwx9QQ0e++U3wdfgltC7/4EWSTg6kO7VBDh2P/70Z3emACVi1lTm0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1615937639; h=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=Z63XpTFYvxamHt5jS4VSP2Pgz2274CpreI23Pi+tpTM=; b=R3DMJYWhGpIipWVO/Zot94wb83augVaXxzj4wBV3qk2DF11Vwg7x7T1iJ9gz4HYApb/yhfWm2u4N9n9dcmeEXc2UId09+Hj1g1dSF4zKWA2luDZuT2MySbAzsxe5q4hcIQlHpUP/YQzln30Clt0ZpGeNbgkcvODh4KgijhKUWNU= 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 1615937639672608.0798157621462; Tue, 16 Mar 2021 16:33:59 -0700 (PDT) Received: from localhost ([::1]:53338 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMJCI-0004jU-Gj for importer@patchew.org; Tue, 16 Mar 2021 19:33:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59832) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMJ9l-0002fR-2P for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:21 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:33384 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 1lMJ9j-0007LO-5v for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:20 -0400 Received: from host109-156-104-46.range109-156.btcentralplus.com ([109.156.104.46] 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 1lMJ9g-0006Mg-PX; Tue, 16 Mar 2021 23:31:22 +0000 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu Date: Tue, 16 Mar 2021 23:30:24 +0000 Message-Id: <20210316233024.13560-5-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> References: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 109.156.104.46 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH 4/4] esp: always check current_req is not NULL before use in DMA callbacks 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" Content-Type: text/plain; charset="utf-8" After issuing a SCSI command the SCSI layer can call the SCSIBusInfo .cancel callback which resets both current_req and current_dev to NULL. If any data is left in the transfer buffer (async_len !=3D 0) then the next TI (Transfer Information) command will attempt to reference the NULL pointer causing a segfault. Buglink: https://bugs.launchpad.net/qemu/+bug/1910723 Buglink: https://bugs.launchpad.net/qemu/+bug/1909247 Signed-off-by: Mark Cave-Ayland --- hw/scsi/esp.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index ae362c9dfb..7216903ce0 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -524,7 +524,9 @@ static void do_dma_pdma_cb(ESPState *s) } =20 if (s->async_len =3D=3D 0) { - scsi_req_continue(s->current_req); + if (s->current_req) { + scsi_req_continue(s->current_req); + } return; } =20 @@ -674,14 +676,16 @@ static void esp_do_dma(ESPState *s) s->ti_size -=3D len; } if (s->async_len =3D=3D 0) { - scsi_req_continue(s->current_req); - /* - * If there is still data to be read from the device then - * complete the DMA operation immediately. Otherwise defer - * until the scsi layer has completed. - */ - if (to_device || esp_get_tc(s) !=3D 0 || s->ti_size =3D=3D 0) { - return; + if (s->current_req) { + scsi_req_continue(s->current_req); + /* + * If there is still data to be read from the device then + * complete the DMA operation immediately. Otherwise defer + * until the scsi layer has completed. + */ + if (to_device || esp_get_tc(s) !=3D 0 || s->ti_size =3D=3D 0) { + return; + } } } =20 @@ -744,10 +748,12 @@ static void esp_do_nodma(ESPState *s) } =20 if (s->async_len =3D=3D 0) { - scsi_req_continue(s->current_req); + if (s->current_req) { + scsi_req_continue(s->current_req); =20 - if (to_device || s->ti_size =3D=3D 0) { - return; + if (to_device || s->ti_size =3D=3D 0) { + return; + } } } =20 --=20 2.20.1