From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34014) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDDUV-0006bB-Q0 for qemu-devel@nongnu.org; Wed, 15 Jun 2016 12:16:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDDUQ-000458-OU for qemu-devel@nongnu.org; Wed, 15 Jun 2016 12:16:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39994) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDDUQ-000452-IJ for qemu-devel@nongnu.org; Wed, 15 Jun 2016 12:16:26 -0400 From: P J P Date: Wed, 15 Jun 2016 21:46:16 +0530 Message-Id: <1466007376-27333-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH v3] 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', the length parameter could exceed the buffer size. Add check 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 | 7 +++++-- include/hw/scsi/esp.h | 3 ++- 2 files changed, 7 insertions(+), 3 deletions(-) Update as per -> https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg04194.html diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 4b94bbc..1208a63 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -249,6 +249,9 @@ static void esp_do_dma(ESPState *s) len = s->dma_left; if (s->do_cmd) { trace_esp_do_dma(s->cmdlen, len); + if (len > sizeof(s->cmdbuf) - s->cmdlen) { + return; + } s->dma_memory_read(s->dma_opaque, &s->cmdbuf[s->cmdlen], len); s->ti_size = 0; s->cmdlen = 0; @@ -348,7 +351,7 @@ 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 +455,7 @@ 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