From: Prasad J Pandit <p...@fedoraproject.org> 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 <ps...@huawei.com> Reported-by: Li Qiang <liqiang...@360.cn> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- 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
