------------------------------------------------------------------------ *From*: P J P *Subject*: [Qemu-devel] [PATCH 1/2] scsi: check command buffer length before write(CVE-2016-4439) *Date*: Thu, 19 May 2016 16:09:30 +0530 ------------------------------------------------------------------------ From: Prasad J Pandit The 53C9X Fast SCSI Controller(FSC) comes with an internal 16-byte FIFO buffer. It is used to handle command and data transfer. While writing to this command buffer 's->cmdbuf[TI_BUFSZ=16]', a check was missing to validate input length. Add check to avoid OOB write access. Fixes CVE-2016-4439 Reported-by: Li Qiang Signed-off-by: Prasad J Pandit --- hw/scsi/esp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/qemu-xen-traditional/hw/esp.c b/tools/qemu-xen-traditional/hw/esp.c index 8961be2..01497e6 100644 --- a/tools/qemu-xen-traditional/hw/esp.c +++ b/tools/qemu-xen-traditional/hw/esp.c @@ -448,7 +448,11 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val) break; case ESP_FIFO: if (s->do_cmd) { - s->cmdbuf[s->cmdlen++] = val & 0xff; + if (s->cmdlen < TI_BUFSZ) { + s->cmdbuf[s->cmdlen++] = val & 0xff; + } else { + ESP_ERROR("fifo overrun\n"); + } } else if (s->ti_size == TI_BUFSZ - 1) { ESP_ERROR("fifo overrun\n"); } else { -- 2.5.5