From nobody Tue Feb 10 10:20:32 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=1617263745; cv=none; d=zohomail.com; s=zohoarc; b=MGtycySsxAt4yxKLs9MfZ12IM6ro9Bz7gvCJEwy6i/lp9ATLJRLtIxLXYUC24P0Bxa4iHilbT1EFdrBHhjvaDjjSmIqbvpIFkGmhZiwbpXJlgeZ9QghS+Fp9dT5nudn0fo+c8UtuvBBH6GjnvUl6e/yVxWvVCPjBF+c5eaRk7js= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1617263745; 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=Pz8nWC2SA8f2VYDoUPhyDs+VNT8tA0l/FEgTukjecrY=; b=bmPIKE1KLi4O/DbzcjmG6u5jJ7/FwdMFk9s/bRE1O4mGhYlXUIgVam4wmdF9ySRJ0fU5belGwEMJ0QfOgeD/u0N6qhW1RsAcPDsQKGmdlWeRXvw2WBboAWbgqBj3AdCAzgVUJ/Rd8cOIj+UwB/p8jJiJjXn5Esgabe7R8oYTsDA= 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 1617263745890593.4535552543462; Thu, 1 Apr 2021 00:55:45 -0700 (PDT) Received: from localhost ([::1]:48328 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lRsB6-0004Py-Sd for importer@patchew.org; Thu, 01 Apr 2021 03:55:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57026) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lRs5j-0005ia-A0 for qemu-devel@nongnu.org; Thu, 01 Apr 2021 03:50:11 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:57038 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 1lRs5h-0000ur-Bt for qemu-devel@nongnu.org; Thu, 01 Apr 2021 03:50:10 -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 1lRs5n-0004IO-IM; Thu, 01 Apr 2021 08:50:19 +0100 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu, laurent@vivier.eu, pbonzini@redhat.com Date: Thu, 1 Apr 2021 08:49:27 +0100 Message-Id: <20210401074933.9923-6-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210401074933.9923-1-mark.cave-ayland@ilande.co.uk> References: <20210401074933.9923-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 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 v3 05/11] esp: introduce esp_fifo_pop_buf() and use it instead of fifo8_pop_buf() 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" The const pointer returned by fifo8_pop_buf() lies directly within the arra= y used to model the FIFO. Building with address sanitisers enabled shows that if t= he caller expects a minimum number of bytes present then if the FIFO is nearly= full, the caller may unexpectedly access past the end of the array. Introduce esp_fifo_pop_buf() which takes a destination buffer and performs a memcpy() in it to guarantee that the caller cannot overwrite the FIFO array= and update all callers to use it. Similarly add underflow protection similar to esp_fifo_push() and esp_fifo_pop() so that instead of triggering an assert() the operation becomes a no-op. 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 | 41 +++++++++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 12 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index ce88866803..1aa2caf57d 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -107,6 +107,7 @@ static void esp_fifo_push(Fifo8 *fifo, uint8_t val) =20 fifo8_push(fifo, val); } + static uint8_t esp_fifo_pop(Fifo8 *fifo) { if (fifo8_is_empty(fifo)) { @@ -116,6 +117,23 @@ static uint8_t esp_fifo_pop(Fifo8 *fifo) return fifo8_pop(fifo); } =20 +static uint32_t esp_fifo_pop_buf(Fifo8 *fifo, uint8_t *dest, int maxlen) +{ + const uint8_t *buf; + uint32_t n; + + if (maxlen =3D=3D 0) { + return 0; + } + + buf =3D fifo8_pop_buf(fifo, maxlen, &n); + if (dest) { + memcpy(dest, buf, n); + } + + return n; +} + static uint32_t esp_get_tc(ESPState *s) { uint32_t dmalen; @@ -240,11 +258,11 @@ static uint32_t get_cmd(ESPState *s, uint32_t maxlen) if (dmalen =3D=3D 0) { return 0; } - memcpy(buf, fifo8_pop_buf(&s->fifo, dmalen, &n), dmalen); - if (dmalen >=3D 3) { + n =3D esp_fifo_pop_buf(&s->fifo, buf, dmalen); + if (n >=3D 3) { buf[0] =3D buf[2] >> 5; } - fifo8_push_all(&s->cmdfifo, buf, dmalen); + fifo8_push_all(&s->cmdfifo, buf, n); } trace_esp_get_cmd(dmalen, target); =20 @@ -257,16 +275,16 @@ static uint32_t get_cmd(ESPState *s, uint32_t maxlen) =20 static void do_busid_cmd(ESPState *s, uint8_t busid) { - uint32_t n, cmdlen; + uint32_t cmdlen; int32_t datalen; int lun; SCSIDevice *current_lun; - uint8_t *buf; + uint8_t buf[ESP_CMDFIFO_SZ]; =20 trace_esp_do_busid_cmd(busid); lun =3D busid & 7; cmdlen =3D fifo8_num_used(&s->cmdfifo); - buf =3D (uint8_t *)fifo8_pop_buf(&s->cmdfifo, cmdlen, &n); + esp_fifo_pop_buf(&s->cmdfifo, buf, cmdlen); =20 current_lun =3D scsi_device_find(&s->bus, 0, s->current_dev->id, lun); s->current_req =3D scsi_req_new(current_lun, 0, lun, buf, s); @@ -299,13 +317,12 @@ static void do_busid_cmd(ESPState *s, uint8_t busid) static void do_cmd(ESPState *s) { uint8_t busid =3D fifo8_pop(&s->cmdfifo); - uint32_t n; =20 s->cmdfifo_cdb_offset--; =20 /* Ignore extended messages for now */ if (s->cmdfifo_cdb_offset) { - fifo8_pop_buf(&s->cmdfifo, s->cmdfifo_cdb_offset, &n); + esp_fifo_pop_buf(&s->cmdfifo, NULL, s->cmdfifo_cdb_offset); s->cmdfifo_cdb_offset =3D 0; } =20 @@ -483,7 +500,7 @@ static void do_dma_pdma_cb(ESPState *s) /* Copy FIFO data to device */ len =3D MIN(s->async_len, ESP_FIFO_SZ); len =3D MIN(len, fifo8_num_used(&s->fifo)); - memcpy(s->async_buf, fifo8_pop_buf(&s->fifo, len, &n), len); + n =3D esp_fifo_pop_buf(&s->fifo, s->async_buf, len); s->async_buf +=3D n; s->async_len -=3D n; s->ti_size +=3D n; @@ -491,7 +508,7 @@ static void do_dma_pdma_cb(ESPState *s) if (n < len) { /* Unaligned accesses can cause FIFO wraparound */ len =3D len - n; - memcpy(s->async_buf, fifo8_pop_buf(&s->fifo, len, &n), len); + n =3D esp_fifo_pop_buf(&s->fifo, s->async_buf, len); s->async_buf +=3D n; s->async_len -=3D n; s->ti_size +=3D n; @@ -667,7 +684,7 @@ static void esp_do_dma(ESPState *s) static void esp_do_nodma(ESPState *s) { int to_device =3D ((s->rregs[ESP_RSTAT] & 7) =3D=3D STAT_DO); - uint32_t cmdlen, n; + uint32_t cmdlen; int len; =20 if (s->do_cmd) { @@ -708,7 +725,7 @@ static void esp_do_nodma(ESPState *s) =20 if (to_device) { len =3D MIN(fifo8_num_used(&s->fifo), ESP_FIFO_SZ); - memcpy(s->async_buf, fifo8_pop_buf(&s->fifo, len, &n), len); + esp_fifo_pop_buf(&s->fifo, s->async_buf, len); s->async_buf +=3D len; s->async_len -=3D len; s->ti_size +=3D len; --=20 2.20.1