From patchwork Thu Apr 1 07:49:27 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: 1460887 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 4F9wSn1czSz9sV5 for ; Thu, 1 Apr 2021 18:54:49 +1100 (AEDT) Received: from localhost ([::1]:46340 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lRsAB-0003XG-86 for incoming@patchwork.ozlabs.org; Thu, 01 Apr 2021 03:54:47 -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 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 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" The const pointer returned by fifo8_pop_buf() lies directly within the array used to model the FIFO. Building with address sanitisers 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 Reviewed-by: Philippe Mathieu-Daudé --- 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) 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); } +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; @@ -240,11 +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); @@ -257,16 +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); @@ -299,13 +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; } @@ -483,7 +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; @@ -491,7 +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; @@ -667,7 +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) { @@ -708,7 +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;