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authorDan McGee <dan@archlinux.org>2011-09-19 08:10:13 -0500
committerMax Kellermann <max@duempel.org>2011-09-19 17:11:09 +0200
commit27946a981ff4192f064feb3117567463c137933f (patch)
tree1e03c0564a65c43ba98a29d8ed7938464e32d3f3 /src/server_socket.c
parent74617389c88ccf630b8cce4b54d9e2fa5afb2259 (diff)
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Set socket TCP keepalive option on incoming connections
If a connected host disappears without our knowledge, as can happen over wireless or a hibernating machine, we continue to hold the port open waiting for messages. Because we never try to send anything down this now-broken pipe, the connection will sit idle taking up a slot in our allowed incoming connections list. If enough of these happen, an unintended Denial of Service takes place, where all connection slots are filled with now-broken, never ending connections. Setting the TCP keepalive option at least allows these to time out after the default two hours, which is sufficient in the non-malicious case. Signed-off-by: Dan McGee <dan@archlinux.org>
Diffstat (limited to '')
-rw-r--r--src/server_socket.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/src/server_socket.c b/src/server_socket.c
index 82ad81f12..fc8dbd17a 100644
--- a/src/server_socket.c
+++ b/src/server_socket.c
@@ -160,12 +160,16 @@ server_socket_in_event(G_GNUC_UNUSED GIOChannel *source,
size_t address_length = sizeof(address);
int fd = accept_cloexec_nonblock(s->fd, (struct sockaddr*)&address,
&address_length);
- if (fd >= 0)
+ if (fd >= 0) {
+ if (socket_keepalive(fd))
+ g_warning("Could not set TCP keepalive option: %s",
+ g_strerror(errno));
s->parent->callback(fd, (const struct sockaddr*)&address,
address_length, get_remote_uid(fd),
s->parent->callback_ctx);
- else
+ } else {
g_warning("accept() failed: %s", g_strerror(errno));
+ }
return true;
}