[Qemu-devel] [PATCH v4 17/30] openpic: avoid buffer overrun on incoming migration

[Michael S. Tsirkin]

From: Michael Roth <address@hidden>

CVE-2013-4534

opp->nb_cpus is read from the wire and used to determine how many
IRQDest elements to read into opp->dst[]. If the value exceeds the
length of opp->dst[], MAX_CPU, opp->dst[] can be overrun with arbitrary
data from the wire.

Fix this by failing migration if the value read from the wire exceeds
MAX_CPU.

Signed-off-by: Michael Roth <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
 hw/intc/openpic.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/intc/openpic.c b/hw/intc/openpic.c
index be76fbd..8cb16da 100644
--- a/hw/intc/openpic.c
+++ b/hw/intc/openpic.c
@@ -1429,6 +1429,9 @@ static int openpic_load(QEMUFile* f, void *opaque, int 
version_id)
     qemu_get_be32s(f, &opp->tfrr);
 
     qemu_get_be32s(f, &opp->nb_cpus);
+    if (opp->nb_cpus > MAX_CPU) {
+        return -EINVAL;
+    }
 
     for (i = 0; i < opp->nb_cpus; i++) {
         qemu_get_sbe32s(f, &opp->dst[i].ctpr);
-- 
MST