From 0a5e3685ea10c578f8063ca0dbb009af45693d85 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Thu, 19 May 2016 16:09:30 +0530 Subject: [PATCH] esp: check command buffer length before write(CVE-2016-4439) 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 Cc: qemu-stable@nongnu.org Signed-off-by: Prasad J Pandit Message-Id: <1463654371-11169-2-git-send-email-ppandit@redhat.com> Signed-off-by: Paolo Bonzini (cherry picked from commit c98c6c105f66f05aa0b7c1d2a4a3f716450907ef) Signed-off-by: Michael Roth Upstream-Status: Backport CVE: CVE-2016-4439 Signed-off-by: Armin Kuster --- hw/scsi/esp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) Index: qemu-2.4.0/hw/scsi/esp.c =================================================================== --- qemu-2.4.0.orig/hw/scsi/esp.c +++ qemu-2.4.0/hw/scsi/esp.c @@ -446,7 +446,11 @@ void esp_reg_write(ESPState *s, uint32_t 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 { + trace_esp_error_fifo_overrun(); + } } else if (s->ti_size == TI_BUFSZ - 1) { trace_esp_error_fifo_overrun(); } else {