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-rw-r--r--drivers/xen/xenbus/xenbus_xs.c6
-rw-r--r--include/xen/interface/io/xs_wire.h3
2 files changed, 9 insertions, 0 deletions
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index b3b8f2f3ad1..6f0121e3be6 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -810,6 +810,12 @@ static int process_msg(void)
goto out;
}
+ if (msg->hdr.len > XENSTORE_PAYLOAD_MAX) {
+ kfree(msg);
+ err = -EINVAL;
+ goto out;
+ }
+
body = kmalloc(msg->hdr.len + 1, GFP_NOIO | __GFP_HIGH);
if (body == NULL) {
kfree(msg);
diff --git a/include/xen/interface/io/xs_wire.h b/include/xen/interface/io/xs_wire.h
index f0b6890370b..3c1877caaef 100644
--- a/include/xen/interface/io/xs_wire.h
+++ b/include/xen/interface/io/xs_wire.h
@@ -88,4 +88,7 @@ struct xenstore_domain_interface {
XENSTORE_RING_IDX rsp_cons, rsp_prod;
};
+/* Violating this is very bad. See docs/misc/xenstore.txt. */
+#define XENSTORE_PAYLOAD_MAX 4096
+
#endif /* _XS_WIRE_H */