From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33246) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDEjw-0005ch-Ih for qemu-devel@nongnu.org; Wed, 15 Jun 2016 13:36:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDEjs-00023S-A2 for qemu-devel@nongnu.org; Wed, 15 Jun 2016 13:36:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46458) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDEjs-00022w-4d for qemu-devel@nongnu.org; Wed, 15 Jun 2016 13:36:28 -0400 From: P J P Date: Wed, 15 Jun 2016 23:06:19 +0530 Message-Id: <1466012179-31839-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH v4] scsi: esp: check length before dma read List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: Paolo Bonzini , Li Qiang , Laszlo Ersek , Prasad J Pandit From: Prasad J Pandit While doing DMA read into ESP command buffer 's->cmdbuf', it could write past the 's->cmdbuf' area, if it was partially filled; ie. 's->cmdlen' wasn't set at the start of the buffer. Check 'len' to avoid OOB access. Also increase the command buffer size to 32, which is maximum when 's->do_cmd' is set. Reported-by: Li Qiang Signed-off-by: Prasad J Pandit --- hw/scsi/esp.c | 6 ++++-- include/hw/scsi/esp.h | 3 ++- 2 files changed, 6 insertions(+), 3 deletions(-) Update as per -> https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg04269.html diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 4b94bbc..cc74ba8 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -249,6 +249,8 @@ static void esp_do_dma(ESPState *s) len = s->dma_left; if (s->do_cmd) { trace_esp_do_dma(s->cmdlen, len); + assert (s->cmdlen <= sizeof(s->cmdbuf) && + len <= sizeof(s->cmdbuf) - s->cmdlen); s->dma_memory_read(s->dma_opaque, &s->cmdbuf[s->cmdlen], len); s->ti_size = 0; s->cmdlen = 0; @@ -348,7 +350,7 @@ static void handle_ti(ESPState *s) s->dma_counter = dmalen; if (s->do_cmd) - minlen = (dmalen < 32) ? dmalen : 32; + minlen = (dmalen < ESP_CMDBUF_SZ) ? dmalen : ESP_CMDBUF_SZ; else if (s->ti_size < 0) minlen = (dmalen < -s->ti_size) ? dmalen : -s->ti_size; else @@ -452,7 +454,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val) break; case ESP_FIFO: if (s->do_cmd) { - if (s->cmdlen < TI_BUFSZ) { + if (s->cmdlen < ESP_CMDBUF_SZ) { s->cmdbuf[s->cmdlen++] = val & 0xff; } else { trace_esp_error_fifo_overrun(); diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h index 6c79527..d2c4886 100644 --- a/include/hw/scsi/esp.h +++ b/include/hw/scsi/esp.h @@ -14,6 +14,7 @@ void esp_init(hwaddr espaddr, int it_shift, #define ESP_REGS 16 #define TI_BUFSZ 16 +#define ESP_CMDBUF_SZ 32 typedef struct ESPState ESPState; @@ -31,7 +32,7 @@ struct ESPState { SCSIBus bus; SCSIDevice *current_dev; SCSIRequest *current_req; - uint8_t cmdbuf[TI_BUFSZ]; + uint8_t cmdbuf[ESP_CMDBUF_SZ]; uint32_t cmdlen; uint32_t do_cmd; -- 2.5.5