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[052/156] zaurus: fix buffer overrun on invalid state load

Message ID 1404839947-1086-53-git-send-email-mdroth@linux.vnet.ibm.com
State New
Headers show

Commit Message

Michael Roth July 8, 2014, 5:17 p.m. UTC 
From: "Michael S. Tsirkin" <mst@redhat.com>

CVE-2013-4540

Within scoop_gpio_handler_update, if prev_level has a high bit set, then
we get bit > 16 and that causes a buffer overrun.

Since prev_level comes from wire indirectly, this can
happen on invalid state load.

Similarly for gpio_level and gpio_dir.

To fix, limit to 16 bit.

Reported-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit 52f91c3723932f8340fe36c8ec8b18a757c37b2b)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/gpio/zaurus.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
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Patch

diff --git a/hw/gpio/zaurus.c b/hw/gpio/zaurus.c
index dc79a8b..8e2ce04 100644
--- a/hw/gpio/zaurus.c
+++ b/hw/gpio/zaurus.c
@@ -203,6 +203,15 @@  static bool is_version_0 (void *opaque, int version_id)
     return version_id == 0;
 }
 
+static bool vmstate_scoop_validate(void *opaque, int version_id)
+{
+    ScoopInfo *s = opaque;
+
+    return !(s->prev_level & 0xffff0000) &&
+        !(s->gpio_level & 0xffff0000) &&
+        !(s->gpio_dir & 0xffff0000);
+}
+
 static const VMStateDescription vmstate_scoop_regs = {
     .name = "scoop",
     .version_id = 1,
@@ -215,6 +224,7 @@  static const VMStateDescription vmstate_scoop_regs = {
         VMSTATE_UINT32(gpio_level, ScoopInfo),
         VMSTATE_UINT32(gpio_dir, ScoopInfo),
         VMSTATE_UINT32(prev_level, ScoopInfo),
+        VMSTATE_VALIDATE("irq levels are 16 bit", vmstate_scoop_validate),
         VMSTATE_UINT16(mcr, ScoopInfo),
         VMSTATE_UINT16(cdr, ScoopInfo),
         VMSTATE_UINT16(ccr, ScoopInfo),