Commit graph

2177 commits

Author SHA1 Message Date
Guus Sliepen
76c90e1639 Non-zero exit code when reloading config file fails after SIGHUP.
When reloading the configuration file via the tinc command, the user will get
an error message if reloading has failed. However, no such warning exists when
sending a HUP signal. Previously, tincd would exit in both cases, but with a
zero exit code. Now it will exit with code 1 when reloading fails after a
SIGHUP, but tincd will keep running if it is signaled via the tinc command.
Instead, the tinc command will exit with a non-zero exit code.
2013-08-02 23:50:44 +02:00
Guus Sliepen
f3a2bed063 Really retry outgoing connections immediately if requested.
The retry() function would only abort connections that were in progress of
being made, it wouldn't reschedule the outgoing connections that had been
sleeping.
2013-08-02 20:53:54 +02:00
Guus Sliepen
1e7d1cd3c7 Clean up the SIGINT handler. 2013-08-02 20:50:19 +02:00
Guus Sliepen
a38e0d6213 Use umask() to set file and UNIX socket permissions without race conditions.
As mentioned by Erik Tews, calling fchmod() after fopen() leaves a small window
for exploits. As long as tinc is single-threaded, we can use umask() instead to
reduce file permissions. This also works when creating the AF_UNIX control socket.

The umask of the user running tinc(d) is used for most files, except for the
private keys, invitation files, PID file and control socket.
2013-08-02 19:28:34 +02:00
Guus Sliepen
a1f4f14c6c Defer handling netname conflicts when accepting an invitation.
In case no explicit netname of configuration directory is specified when
accepting an invitation, the netname specified in the invitation data is
used. However, this new netname is only known after making the connection
to the server. If the new netname conflicts with an existing one at the
client, we ask the user for a netname that doesn't conflict. However, we
should first finish accepting the invitation, so we don't run into the
problem that the server times out and cancels the invitation. So, we create
a random netname and store the files there, and only after we finish
accepting the invitation we ask the user for a better netname, and then
just rename the temporary directory to the final name.
2013-07-26 15:48:52 +02:00
Guus Sliepen
d47c79533f Make absolutely sure we can write config files before accepting an invitation. 2013-07-26 15:44:05 +02:00
Guus Sliepen
37cca72e6c Choose a different Port when 655 isn't available when doing "tinc join". 2013-07-26 14:53:36 +02:00
Guus Sliepen
8f2db4afdd Choose a different Port when 655 isn't available when doing "tinc init".
If port 655 cannot be bound to when using the init command, tinc will try to
find a random port number that can be bound to, and will add the appropriate
Port variable to its host config file. A warning will be printed as well.
2013-07-26 14:17:15 +02:00
Guus Sliepen
d6a67266c8 Don't forget the Port variable when creating an invitation URL. 2013-07-25 17:30:47 +02:00
Guus Sliepen
d1e01bc880 Allow control-C to stop tincd without stopping the tinc shell. 2013-07-25 17:30:47 +02:00
Guus Sliepen
d219fe2c09 Warn when incorrect use of add or set causes variables to be removed. 2013-07-25 17:30:47 +02:00
Guus Sliepen
e624969568 Fix compression when using the SPTPS protocol. 2013-07-24 20:48:31 +02:00
Guus Sliepen
5fca595b80 Honour umask, let temporary key files inherit original's permissions.
During the init command, tinc changed the umask to 077 when writing the public
and private key files, to prevent the temporary copies from being world
readable. However, subsequently created files would therefore also be
unreadable for others. Now we don't change the umask anymore, therefore
allowing the user to choose whether the files are world readable or not by
setting the umask as desired. The private key files are still made unreadable
for others of course. Temporary files now inherit the permissions of the
original, and the tinc-up script's permissions now also honour the umask.
2013-07-22 23:05:07 +02:00
Etienne Dechamps
ae85a02030 Further improve bandwidth estimation for type 2 MTU probe replies.
This patch adds timestamp information to type 2 MTU probe replies. This
timestamp can then be used by the recipient to estimate bandwidth more
accurately, as jitter in the RX direction won't affect the results.
2013-07-22 21:25:44 +01:00
Etienne Dechamps
e3c763eae8 Introduce lightweight PMTU probe replies.
When replying to a PMTU probe, tinc sends a packet with the same length
as the PMTU probe itself, which is usually large (~1450 bytes). This is
not necessary: the other node wants to know the size of the PMTU probes
that have been received, but encoding this information as the actual
reply length is probably the most inefficient way to do it. It doubles
the bandwidth usage of the PMTU discovery process, and makes it less
reliable since large packets are more likely to be dropped.

This patch introduces a new PMTU probe reply type, encoded as type "2"
in the first byte of the packet, that indicates that the length of the
PMTU probe that is being replied to is encoded in the next two bytes of
the packet. Thus reply packets are only 3 bytes long.

(This also protects against very broken networks that drop very small
packets - yes, I've seen it happen on a subnet of a national ISP - in
such a case the PMTU probe replies will be dropped, and tinc won't
enable UDP communication, which is a good thing.)

Because legacy nodes won't understand type 2 probe replies, the minor
protocol number is bumped to 3.

Note that this also improves bandwidth estimation, as it is able to
measure bandwidth in both directions independently (the node receiving
the replies is measuring in the TX direction) and the use of smaller
reply packets might decrease the influence of jitter.
2013-07-22 21:25:37 +01:00
Etienne Dechamps
e3a4672afb Disable PMTU discovery when TCPOnly is set.
Obviously, PMTU discovery doesn't make much sense when we know we'll be
using TCP anyway.
2013-07-21 00:36:28 +02:00
Guus Sliepen
b03bbaa385 Allow extra options to be passed to "tinc restart" again. 2013-07-21 00:20:54 +02:00
Guus Sliepen
e82bec6670 Forbid protocol version rollback.
When we know a node's ECDSA key, we only allow communication via the SPTPS
protocol.
2013-07-21 00:13:38 +02:00
Guus Sliepen
fab2965d38 Attribution for Etienne Dechamps. 2013-07-20 23:41:01 +02:00
Etienne Dechamps
51c1639884 Fix hash_function().
The hashing function that tinc uses is currently broken as it only looks
at the first 4 bytes of data.

This leads to interesting bugs, like the node UDP address cache being
subtly broken because two addresses with the same protocol and port (but
not the same IP address) will override each other. This is because
the first four bytes of sockaddr_in contains the IP protocol and port,
while the IP address itself is contained in the four remaining bytes
that are never used when the hash is computed.
2013-07-20 23:31:19 +02:00
Guus Sliepen
1828908148 Don't use vasprintf() anymore on Windows.
Windows doesn't actually support it, but MinGW provides it. However, with some versions of
MinGW it doesn't work correctly. Instead, we vsnprintf() to a local buffer and xstrdup() the
results.
2013-07-17 18:06:56 +02:00
Guus Sliepen
54127996ca Don't search in local directories for include files.
Tinc's source code doesn't rely on this anymore, and this gets rid of potential conflicts with
system headers.
2013-07-17 18:02:07 +02:00
Guus Sliepen
fb1e69072e Add missing definitions on Windows. 2013-07-17 18:00:40 +02:00
Guus Sliepen
918067f117 Fix warning "Both netname and configuration directory given" on Windows. 2013-07-15 14:48:43 +02:00
Etienne Dechamps
633b7cbb45 Fix combination of Mode = router and DeviceType = tap on Linux.
I believe I have found a bug in tinc on Linux when it is used with
Mode = router and DeviceType = tap. This combination is useful because
it allows global broadcast packets to be used in router mode. However,
when tinc receives a packet in this situation, it needs to make sure its
destination MAC address matches the address of the TAP adapter, which is
typically not the case since the sending node doesn't know the MAC
address of the recipient. Unfortunately, this is not the case on Linux,
which breaks connectivity.
2013-07-15 00:28:35 +02:00
Guus Sliepen
24e3ec863e Add connection rate limiting.
Tinc now strictly limits incoming connections from the same host to 1 per
second. For incoming connections from multiple hosts short bursts of incoming
connections are allowed (by default 100), but on average also only 1 connection
per second is allowed.

When an incoming connection exceeds the limit, tinc will keep the connection in
a tarpit; the connection will be kept open but it is ignored completely. Only
one connection is in a tarpit at a time to limit the number of useless open
connections.
2013-07-11 23:38:38 +02:00
Guus Sliepen
2eba793305 Set $NAME when calling host-up/down and subnet-up/down scripts. 2013-07-05 21:36:51 +02:00
Guus Sliepen
b811e980e3 Add the LocalDiscoveryAddress option.
When LocalDiscovery is enabled, tinc normally sends broadcast packets during
PMTU discovery to the broadcast address (255.255.255.255 or ff02::1). This
option lets tinc use a different address.

At the moment only one LocalDiscoveryAddress can be specified.
2013-05-31 18:50:34 +02:00
Guus Sliepen
e92b2004e2 Use strerror() instead of gai_strerror() when err == EAI_SYSTEM. 2013-05-31 17:23:00 +02:00
Guus Sliepen
ce5e0f6557 Allow the log output to be stopped with control-C in tinc's shell. 2013-05-30 17:38:48 +02:00
Guus Sliepen
6bf3595a91 Better optional argument handling.
Some options can take an optional argument. However, in this case GNU getopt
requires that the optional argument is right next to the option without
whitespace inbetween. If there is whitespace, getopt will treat it as a
non-option argument, but tincd ignored those without a warning. Now tincd will
allow optional arguments with whitespace inbetween, and will give an error when
it encounters any other non-option arguments.

The tinc binary now requires that all options for itself are given before the
command.
2013-05-30 16:53:16 +02:00
Guus Sliepen
ced4c1a327 Add an invitation protocol.
Using the tinc command, an administrator of an existing VPN can generate
invitations for new nodes. The invitation is a small URL that can easily
be copy&pasted into email or live chat. Another person can have tinc
automatically setup the necessary configuration files and exchange keys
with the server, by only using the invitation URL.

The invitation protocol uses temporary ECDSA keys. The invitation URL
consists of the hostname and port of the server, a hash of the server's
temporary ECDSA key and a cookie. When the client wants to accept an
invitation, it also creates a temporary ECDSA key, connects to the server
and says it wants to accept an invitation. Both sides exchange their
temporary keys. The client verifies that the server's key matches the hash
in the invitation URL. After setting up an SPTPS connection using the
temporary keys, the client gives the cookie to the server. If the cookie
is valid, the server sends the client an invitation file containing the
client's new name and a copy of the server's host config file. If everything
is ok, the client will generate a long-term ECDSA key and send it to the
server, which will add it to a new host config file for the client.

The invitation protocol currently allows multiple host config files to be
send from the server to the client. However, the client filters out
most configuration variables for its own host configuration file. In
particular, it only accepts Name, Mode, Broadcast, ConnectTo, Subnet and
AutoConnect. Also, at the moment no tinc-up script is generated.

When an invitation has succesfully been accepted, the client needs to start
the tinc daemon manually.
2013-05-29 18:31:10 +02:00
Guus Sliepen
12e68b95e6 Fix port number in pidfile. 2013-05-28 13:41:53 +02:00
Guus Sliepen
cbe03b0932 Add a newline when logging to stderr in the tinc binary. 2013-05-28 13:40:32 +02:00
Guus Sliepen
c3d357af6c Improve base64 encoding/decoding, add URL-safe variant.
b64decode() now returns length 0 when an invalid character was encountered.
2013-05-28 13:39:15 +02:00
Guus Sliepen
ad93dc3a4b Annotate the xalloc functions.
Most important is the annotation of xasprintf() with the format attribute,
which allows the compiler to give warnings about the format string and
arguments.
2013-05-28 13:36:26 +02:00
Guus Sliepen
bc87b45003 Send a new key when we receive packets from a node we don't have a valid key for. 2013-05-18 16:11:30 +02:00
Guus Sliepen
a9b80226e1 Enable and fix warnings from automake. 2013-05-15 13:55:06 +02:00
Sven-Haegar Koch
a518f82af7 Modified some error messages in src/sptps.c. 2013-05-15 13:53:13 +02:00
Guus Sliepen
fa20cfceec Don't try to handle incoming data if sptps_start() has not been called yet. 2013-05-12 13:39:22 +02:00
Guus Sliepen
52f64cdf95 Fix potential NULL pointer dereferences. 2013-05-11 16:54:50 +02:00
Guus Sliepen
d03dc91e27 Don't free ephemeral ECDH keys twice.
ecdh_compute_shared() was changed to immediately delete the ephemeral key after
the shared secret was computed.  Therefore, the pointer to the ecdh_t struct
should be zeroed so it won't be freed again when a struct sptps_t is freed.
2013-05-11 14:14:20 +02:00
Guus Sliepen
fc119fb009 Use read_host_config() where appropriate. 2013-05-11 14:05:28 +02:00
Guus Sliepen
3c163a3796 Fix check for presence of ECDSA public key for outgoing connections.
At this point, c->config_tree may or may not be NULL, but this does not tell us whether it is an
outgoing connection or not. For incoming connections, we do not know the peer's name yet,
so we always have to claim ECDSA support. For outgoing connections, we always need to check
whether we have the peer's ECDSA public key, so that if we don't, we correctly tell the peer that
we want to upgrade.
2013-05-11 14:04:39 +02:00
Guus Sliepen
c83c2d080f Enable the SPTPS protocol by default. 2013-05-10 21:18:32 +02:00
Guus Sliepen
ee34ac3d61 Add a few more checks and warnings in the crypto functions. 2013-05-10 20:55:52 +02:00
Guus Sliepen
214060ef20 Fix warnings for functions marked __attribute((warn_unused_result)). 2013-05-10 20:30:47 +02:00
Guus Sliepen
7b949262c4 Add __attribute__((warn_unused_result)) to crypto functions. 2013-05-10 20:23:01 +02:00
Guus Sliepen
45063953fd Add more __attribute__((malloc)) where appropriate. 2013-05-10 20:15:27 +02:00
Guus Sliepen
0acdce222f Add generic crypto headers.
They should have been included in commit 9b9230a.
2013-05-01 17:58:30 +02:00