File 0089-lsi53c895a-check-message-length-val.patch of Package qemu-linux-user.9686

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File 0089-lsi53c895a-check-message-length-val.patch of Package qemu-linux-user.9686 (Revision 9732b46f97464e1fad0552821a5e9ef9)

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From 9920c8955adf638855870b7e0690239b879c758e 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 191505df5b..2dffff0d23 100644
--- a/hw/scsi/lsi53c895a.c
+++ b/hw/scsi/lsi53c895a.c
@@ -865,10 +865,11 @@ 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);
@@ -1703,8 +1704,10 @@ static uint8_t lsi_reg_readb(LSIState *s, int offset)
         break;
     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];
+        }
         ret = 0;
         break;
     case 0x59: /* SBDL high */
@@ -2096,11 +2099,23 @@ static int lsi_pre_save(void *opaque)
     return 0;
 }
 
+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,
     .pre_save = lsi_pre_save,
+    .post_load = lsi_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_PCI_DEVICE(parent_obj, LSIState),

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File 0089-lsi53c895a-check-message-length-val.patch of Package qemu-linux-user.9686 (Revision 9732b46f97464e1fad0552821a5e9ef9)

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