From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05CF3C433B4 for ; Wed, 7 Apr 2021 20:00:04 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id A5A5861159 for ; Wed, 7 Apr 2021 20:00:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A5A5861159 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ilande.co.uk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45312 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lUELK-0000EL-Ol for qemu-devel@archiver.kernel.org; Wed, 07 Apr 2021 16:00:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51606) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUEK3-00071u-6D for qemu-devel@nongnu.org; Wed, 07 Apr 2021 15:58:43 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:37760 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 1lUEK1-0007M1-5k for qemu-devel@nongnu.org; Wed, 07 Apr 2021 15:58:42 -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 1lUEK9-00073W-HY; Wed, 07 Apr 2021 20:58:54 +0100 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu, laurent@vivier.eu, pbonzini@redhat.com Date: Wed, 7 Apr 2021 20:57:54 +0100 Message-Id: <20210407195801.685-6-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-Transfer-Encoding: 8bit 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 05/12] 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 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The const pointer returned by fifo8_pop_buf() lies directly within the array used to model the FIFO. Building with address sanitizers enabled shows that if the 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 Tested-by: Alexander Bulekov --- hw/scsi/esp.c | 40 ++++++++++++++++++++++++++++------------ 1 file changed, 28 insertions(+), 12 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index ff8fa73de9..1aa2caf57d 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -117,6 +117,23 @@ static uint8_t esp_fifo_pop(Fifo8 *fifo) return fifo8_pop(fifo); } +static uint32_t esp_fifo_pop_buf(Fifo8 *fifo, uint8_t *dest, int maxlen) +{ + const uint8_t *buf; + uint32_t n; + + if (maxlen == 0) { + return 0; + } + + buf = 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; @@ -241,11 +258,11 @@ static uint32_t get_cmd(ESPState *s, uint32_t maxlen) if (dmalen == 0) { return 0; } - memcpy(buf, fifo8_pop_buf(&s->fifo, dmalen, &n), dmalen); - if (dmalen >= 3) { + n = esp_fifo_pop_buf(&s->fifo, buf, dmalen); + if (n >= 3) { buf[0] = buf[2] >> 5; } - fifo8_push_all(&s->cmdfifo, buf, dmalen); + fifo8_push_all(&s->cmdfifo, buf, n); } trace_esp_get_cmd(dmalen, target); @@ -258,16 +275,16 @@ static uint32_t get_cmd(ESPState *s, uint32_t maxlen) 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]; trace_esp_do_busid_cmd(busid); lun = busid & 7; cmdlen = fifo8_num_used(&s->cmdfifo); - buf = (uint8_t *)fifo8_pop_buf(&s->cmdfifo, cmdlen, &n); + esp_fifo_pop_buf(&s->cmdfifo, buf, cmdlen); current_lun = scsi_device_find(&s->bus, 0, s->current_dev->id, lun); s->current_req = scsi_req_new(current_lun, 0, lun, buf, s); @@ -300,13 +317,12 @@ static void do_busid_cmd(ESPState *s, uint8_t busid) static void do_cmd(ESPState *s) { uint8_t busid = fifo8_pop(&s->cmdfifo); - uint32_t n; s->cmdfifo_cdb_offset--; /* 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 = 0; } @@ -484,7 +500,7 @@ static void do_dma_pdma_cb(ESPState *s) /* Copy FIFO data to device */ len = MIN(s->async_len, ESP_FIFO_SZ); len = MIN(len, fifo8_num_used(&s->fifo)); - memcpy(s->async_buf, fifo8_pop_buf(&s->fifo, len, &n), len); + n = esp_fifo_pop_buf(&s->fifo, s->async_buf, len); s->async_buf += n; s->async_len -= n; s->ti_size += n; @@ -492,7 +508,7 @@ static void do_dma_pdma_cb(ESPState *s) if (n < len) { /* Unaligned accesses can cause FIFO wraparound */ len = len - n; - memcpy(s->async_buf, fifo8_pop_buf(&s->fifo, len, &n), len); + n = esp_fifo_pop_buf(&s->fifo, s->async_buf, len); s->async_buf += n; s->async_len -= n; s->ti_size += n; @@ -668,7 +684,7 @@ static void esp_do_dma(ESPState *s) static void esp_do_nodma(ESPState *s) { int to_device = ((s->rregs[ESP_RSTAT] & 7) == STAT_DO); - uint32_t cmdlen, n; + uint32_t cmdlen; int len; if (s->do_cmd) { @@ -709,7 +725,7 @@ static void esp_do_nodma(ESPState *s) if (to_device) { len = 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 += len; s->async_len -= len; s->ti_size += len; -- 2.20.1