From a1c9b6747da5f3d2815a0c186473dc76d9e4f682 Mon Sep 17 00:00:00 2001 From: imxcc Date: Mon, 21 Jun 2021 17:20:55 +0800 Subject: [PATCH] fix cve-2020-35505 esp: ensure cmdfifo is not empty and current_dev is non-NULL Signed-off-by: Mark Cave-Ayland Signed-off-by: imxcc --- hw/scsi/esp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index d1f13b350e..db6bed4f00 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -79,6 +79,7 @@ void esp_request_cancelled(SCSIRequest *req) scsi_req_unref(s->current_req); s->current_req = NULL; s->current_dev = NULL; + s->async_len = 0; } } @@ -113,7 +114,6 @@ static uint32_t get_cmd(ESPState *s, uint8_t *buf, uint8_t buflen) if (s->current_req) { /* Started a new command before the old one finished. Cancel it. */ scsi_req_cancel(s->current_req); - s->async_len = 0; } s->current_dev = scsi_device_find(&s->bus, 0, target, 0); @@ -136,6 +136,9 @@ static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid) trace_esp_do_busid_cmd(busid); lun = busid & 7; + if (!s->current_dev) { + return; + } current_lun = scsi_device_find(&s->bus, 0, s->current_dev->id, lun); s->current_req = scsi_req_new(current_lun, 0, lun, buf, s); datalen = scsi_req_enqueue(s->current_req); -- 2.27.0