From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47517) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b7hyR-000146-CZ for qemu-devel@nongnu.org; Tue, 31 May 2016 07:36:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b7hyO-0000VP-6S for qemu-devel@nongnu.org; Tue, 31 May 2016 07:36:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37952) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b7hyO-0000VF-0i for qemu-devel@nongnu.org; Tue, 31 May 2016 07:36:36 -0400 From: P J P Date: Tue, 31 May 2016 17:06:21 +0530 Message-Id: <1464694581-31596-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH v2] 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: Peter Maydell , Paolo Bonzini , Huawei PSIRT , Li Qiang , 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. Add check to avoid OOB r/w access. Reported-by: Huawei PSIRT Reported-by: Li Qiang Signed-off-by: Prasad J Pandit --- hw/scsi/esp.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) Update as per -> https://lists.gnu.org/archive/html/qemu-devel/2016-05/msg05506.html diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 591c817..60c1b28 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -400,16 +400,14 @@ uint64_t esp_reg_read(ESPState *s, uint32_t saddr) trace_esp_mem_readb(saddr, s->rregs[saddr]); switch (saddr) { case ESP_FIFO: - if (s->ti_size > 0) { + if ((s->rregs[ESP_RSTAT] & STAT_PIO_MASK) == 0) { + /* Data out. */ + qemu_log_mask(LOG_UNIMP, "esp: PIO data read not implemented\n"); + s->rregs[ESP_FIFO] = 0; + esp_raise_irq(s); + } else if (s->ti_rptr < s->ti_wptr) { s->ti_size--; - if ((s->rregs[ESP_RSTAT] & STAT_PIO_MASK) == 0) { - /* Data out. */ - qemu_log_mask(LOG_UNIMP, - "esp: PIO data read not implemented\n"); - s->rregs[ESP_FIFO] = 0; - } else { - s->rregs[ESP_FIFO] = s->ti_buf[s->ti_rptr++]; - } + s->rregs[ESP_FIFO] = s->ti_buf[s->ti_rptr++]; esp_raise_irq(s); } if (s->ti_size == 0) { @@ -456,7 +454,7 @@ 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