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From: David Herrmann <dh.herrmann@gmail.com>
Date: Tue, 26 May 2015 10:01:37 +0200
Subject: [PATCH] kdbus: make metadata on broadcasts reliable
If we cannot collect metadata, this is a serious error. Don't try to
continue sending a message, but immediately bail out and tell the receiver
that we dropped it. Otherwise, the receiver cannot rely on metadata to be
present and might assume it's a faked connection.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Daniel Mack <daniel@zonque.org>
---
ipc/kdbus/bus.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/ipc/kdbus/bus.c b/ipc/kdbus/bus.c
index 9a0ecbc9df2f..d5475961b896 100644
--- a/ipc/kdbus/bus.c
+++ b/ipc/kdbus/bus.c
@@ -293,12 +293,12 @@ void kdbus_bus_broadcast(struct kdbus_bus *bus,
if (!kdbus_conn_policy_talk(conn_dst, NULL, conn_src))
continue;
- /*
- * Keep sending messages even if we cannot acquire the
- * requested metadata. It's up to the receiver to drop
- * messages that lack expected metadata.
- */
- kdbus_kmsg_collect_metadata(kmsg, conn_src, conn_dst);
+ ret = kdbus_kmsg_collect_metadata(kmsg, conn_src,
+ conn_dst);
+ if (ret < 0) {
+ kdbus_conn_lost_message(conn_dst);
+ continue;
+ }
} else {
/*
* Check if there is a policy db that prevents the
@@ -344,14 +344,14 @@ void kdbus_bus_eavesdrop(struct kdbus_bus *bus,
down_read(&bus->conn_rwlock);
list_for_each_entry(conn_dst, &bus->monitors_list, monitor_entry) {
- /*
- * Collect metadata requested by the destination connection.
- * Ignore errors, as receivers need to check metadata
- * availability, anyway. So it's still better to send messages
- * that lack data, than to skip it entirely.
- */
- if (conn_src)
- kdbus_kmsg_collect_metadata(kmsg, conn_src, conn_dst);
+ if (conn_src) {
+ ret = kdbus_kmsg_collect_metadata(kmsg, conn_src,
+ conn_dst);
+ if (ret < 0) {
+ kdbus_conn_lost_message(conn_dst);
+ continue;
+ }
+ }
ret = kdbus_conn_entry_insert(conn_src, conn_dst, kmsg, NULL);
if (ret < 0)
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