File 0457-lsi53c895a-check-message-length-val.patch of Package qemu.9344

From 45c04c4b48f397b5b0a0772eda4e09d1b3601239 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 5 Nov 2018 13:03:53 -0700
Subject: [PATCH] lsi53c895a: check message length value is valid

While writing a message in 'lsi_do_msgin', message length value
in 'msg_len' could be invalid due to an invalid migration stream.
Add an assertion to avoid an out of bounds access, and reject
the incoming migration data if it contains an invalid message
length.

Discovered by Deja vu Security. Reported by Oracle.

Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-Id: <20181026194314.18663-1-ppandit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[BR: BSC#1114422 CVE-2018-18849]
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 hw/scsi/lsi53c895a.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
index cb30414849..b8eeade3da 100644
--- a/hw/scsi/lsi53c895a.c
+++ b/hw/scsi/lsi53c895a.c
@@ -827,10 +827,11 @@ static void lsi_do_status(LSIState *s)
 
 static void lsi_do_msgin(LSIState *s)
 {
-    int len;
+    uint8_t len;
     DPRINTF("Message in len=%d/%d\n", s->dbc, s->msg_len);
     s->sfbr = s->msg[0];
     len = s->msg_len;
+    assert(len > 0 && len <= LSI_MAX_MSGIN_LEN);
     if (len > s->dbc)
         len = s->dbc;
     pci_dma_write(PCI_DEVICE(s), s->dnad, s->msg, len);
@@ -1618,8 +1619,10 @@ static uint8_t lsi_reg_readb(LSIState *s, int offset)
         return s->ccntl1;
     case 0x58: /* SBDL */
         /* Some drivers peek at the data bus during the MSG IN phase.  */
-        if ((s->sstat1 & PHASE_MASK) == PHASE_MI)
+        if ((s->sstat1 & PHASE_MASK) == PHASE_MI) {
+            assert(s->msg_len > 0);
             return s->msg[0];
+        }
         return 0;
     case 0x59: /* SBDL high */
         return 0;
@@ -1990,12 +1993,24 @@ static void lsi_pre_save(void *opaque)
     assert(QTAILQ_EMPTY(&s->queue));
 }
 
+static int lsi_post_load(void *opaque, int version_id)
+{
+    LSIState *s = opaque;
+
+    if (s->msg_len < 0 || s->msg_len > LSI_MAX_MSGIN_LEN) {
+        return -EINVAL;
+    }
+
+    return 0;
+}
+
 static const VMStateDescription vmstate_lsi_scsi = {
     .name = "lsiscsi",
     .version_id = 0,
     .minimum_version_id = 0,
     .minimum_version_id_old = 0,
     .pre_save = lsi_pre_save,
+    .post_load = lsi_post_load,
     .fields      = (VMStateField []) {
         VMSTATE_PCI_DEVICE(parent_obj, LSIState),