[systemd-devel] Suspicious assertions in resolved

[Topi Miettinen]

Hello,

I think resolved_manager.c function manager_recv() has an assertion that
could be triggerable by the server sending an oversized packet:

        assert(!(mh.msg_flags & MSG_TRUNC));

The other assertions look suspicious too but I don't know if they can
really be triggered by the other side.

I'd propose something like this:

diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c
index 0594479..b1defa3 100644
--- a/src/resolve/resolved-manager.c
+++ b/src/resolve/resolved-manager.c
@@ -894,7 +894,8 @@ int manager_recv(Manager *m, int fd, DnsProtocol
protocol, DnsPacket **ret) {
                 return -EIO;

         assert(!(mh.msg_flags & MSG_CTRUNC));
-        assert(!(mh.msg_flags & MSG_TRUNC));
+        if (mh.msg_flags & MSG_TRUNC)
+                return -EIO;

         p->size = (size_t) l;


-Topi