From 674ffb2f6dfc750bb719e7e90d8f03ba8d23d7e4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C5=99emysl=20Janouch?= Date: Tue, 9 Jan 2018 05:48:32 +0100 Subject: [PATCH] kike: handle accept() errors better Might prevent some denial of service attacks. --- kike.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/kike.c b/kike.c index 92fd482..dfd896f 100644 --- a/kike.c +++ b/kike.c @@ -3379,20 +3379,25 @@ irc_try_fetch_client (struct server_context *ctx, int listen_fd) int fd = accept (listen_fd, (struct sockaddr *) &peer, &peer_len); if (fd == -1) { - if (errno == EAGAIN) + if (errno == EAGAIN || errno == EWOULDBLOCK) return false; - if (errno == EINTR - || errno == ECONNABORTED) + if (errno == EINTR) return true; - // TODO: handle resource exhaustion (EMFILE, ENFILE) specially - // (stop accepting new connections and wait until we close some; - // also set a timer in case of ENFILE). - print_fatal ("%s: %s", "accept", strerror (errno)); - irc_initiate_quit (ctx); - return false; + if (errno == EBADF + || errno == EINVAL + || errno == ENOTSOCK + || errno == EOPNOTSUPP) + print_fatal ("%s: %s", "accept", strerror (errno)); + + // OS kernels may return a wide range of unforeseeable errors. + // Assuming that they're either transient or caused by + // a connection that we've just extracted from the queue. + print_warning ("%s: %s", "accept", strerror (errno)); + return true; } + hard_assert (peer_len <= sizeof peer); set_blocking (fd, false); // A little bit questionable once the traffic gets high enough (IMO),