tree-wide: use recvmsg_safe() at various places

Let's be extra careful whenever we return from recvmsg() and see
MSG_CTRUNC set. This generally means we ran into a programming error, as
we didn't size the control buffer large enough. It's an error condition
we should at least log about, or propagate up. Hence do that.

This is particularly important when receiving fds, since for those the
control data can be of any size. In particular on stream sockets that's
nasty, because if we miss an fd because of control data truncation we
cannot recover, we might not even realize that we are one off.

(Also, when failing early, if there's any chance the socket might be
AF_UNIX let's close all received fds, all the time. We got this right
most of the time, but there were a few cases missing. God, UNIX is hard
to use)

1 files changed, 1 insertions, 0 deletions

diff --git a/src/journal/journald-stream.c b/src/journal/journald-stream.c
index 609af506a4..ec6dad62e8 100644
--- a/src/journal/journald-stream.c
+++ b/src/journal/journald-stream.c
@@ -545,6 +545,7 @@ static int stdout_stream_process(sd_event_source *es, int fd, uint32_t revents,
                 if (cmsg->cmsg_level == SOL_SOCKET &&
                     cmsg->cmsg_type == SCM_CREDENTIALS &&
                     cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
+                        assert(!ucred);
                         ucred = (struct ucred *)CMSG_DATA(cmsg);
                         break;
                 }