From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46056) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b7SP0-0000T9-QW for qemu-devel@nongnu.org; Mon, 30 May 2016 14:59:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b7SOy-0001GQ-Vg for qemu-devel@nongnu.org; Mon, 30 May 2016 14:59:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33848) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b7SOy-0001GM-QD for qemu-devel@nongnu.org; Mon, 30 May 2016 14:59:00 -0400 From: P J P Date: Tue, 31 May 2016 00:28:48 +0530 Message-Id: <1464634728-8723-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH] scsi: esp: check TI buffer index before read/write List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: Paolo Bonzini , Huawei PSIRT , Prasad J Pandit From: Prasad J Pandit The 53C9X Fast SCSI Controller(FSC) comes with internal 16-byte FIFO buffers. One is used to handle commands and other is for information transfer. While reading/writing to these buffers an index into 's->ti_buf[TI_BUFSZ=16]' could exceed its size, as a check was missing to validate it. Add check to avoid OOB r/w access. Reported-by: Huawei PSIRT Signed-off-by: Prasad J Pandit --- hw/scsi/esp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 591c817..80e4287 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -407,8 +407,10 @@ uint64_t esp_reg_read(ESPState *s, uint32_t saddr) qemu_log_mask(LOG_UNIMP, "esp: PIO data read not implemented\n"); s->rregs[ESP_FIFO] = 0; - } else { + } else if (s->ti_rptr < TI_BUFSZ) { s->rregs[ESP_FIFO] = s->ti_buf[s->ti_rptr++]; + } else { + trace_esp_error_fifo_overrun(); } esp_raise_irq(s); } @@ -456,7 +458,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val) } else { trace_esp_error_fifo_overrun(); } - } else if (s->ti_size == TI_BUFSZ - 1) { + } else if (s->ti_wptr == TI_BUFSZ - 1) { trace_esp_error_fifo_overrun(); } else { s->ti_size++; -- 2.5.5