From 27fa5e735a267d21b3ae040b059636d5063bb7e4 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Thu, 16 Jun 2016 00:22:35 +0200 Subject: [PATCH] scsi: esp: make cmdbuf big enough for maximum CDB size While doing DMA read into ESP command buffer 's->cmdbuf', it could write past the 's->cmdbuf' area, if it was transferring more than 16 bytes. Increase the command buffer size to 32, which is maximum when 's->do_cmd' is set, and add a check on 'len' to avoid OOB access. Reported-by: Li Qiang Signed-off-by: Prasad J Pandit Signed-off-by: Paolo Bonzini (cherry picked from commit 926cde5f3e4d2504ed161ed0cb771ac7cad6fd11) Signed-off-by: Michael Roth --- hw/scsi/esp.c | 6 ++++-- include/hw/scsi/esp.h | 3 ++- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 68d3e4d11b..b4601ad4ea 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -248,6 +248,8 @@ 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); return; } @@ -345,7 +347,7 @@ 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 @@ -451,7 +453,7 @@ 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 6c795276c9..d2c48869e1 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;