If a message is sent to multiple destinations, each destination might
request a different set of metadata. Hence, we cannot rely on each one
requesting at least a single bit.
Fix the message exporter to properly reset the metadata iovec on each
emit-iteration. Otherwise, we might end up scanning random heap memory if
a following destination does not request metadata.
Reported-by: Jan Alexander Steffens <[email protected]>
Signed-off-by: David Herrmann <[email protected]>
---
Hi Greg
One fall-out from the rewrite of the message importer. Reported by Jan. This
fixes some issues with metadata on messages targeted at more than one
destination. Reproducible by running a debug-monitor (which thus gets any
messages, additionally to the normal receiver).
Thanks
David
ipc/kdbus/message.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/ipc/kdbus/message.c b/ipc/kdbus/message.c
index 64763ea..3520f45 100644
--- a/ipc/kdbus/message.c
+++ b/ipc/kdbus/message.c
@@ -946,6 +946,16 @@ struct kdbus_pool_slice *kdbus_staging_emit(struct kdbus_staging *staging,
++v;
msg_size = KDBUS_ALIGN8(msg_size) + meta_size;
+ } else {
+ /* metadata items */
+ v->iov_len = 0;
+ v->iov_base = (void __user *)zeros;
+ ++v;
+
+ /* padding after metadata */
+ v->iov_len = 0;
+ v->iov_base = (void __user *)zeros;
+ ++v;
}
/* ... payload iovecs are already filled in ... */
--
2.4.5