From: Prasad J Pandit <p...@fedoraproject.org> 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 <liqiang...@360.cn> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- 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