SSL_OP_NO_COMPRESSION was presumably added in an attempt to prevent
information leakage in a manner similar to recent attacks on HTTPS.
However, assuming that IRC is vulnerable to the same class of attacks is
incorrect: the behavior of the IRC protocol (a single long-running
connection) is not the same as that of HTTPS (multiple ephemeral
connections). HTTPS's use of ephemeral connections means that certain
assumptions can be made about the contents of the compression
algorithm's dictionaries and the content exchanged between the client
and server (e.g. the content being nearly the same for each connection),
which is not true for IRC. Additionally, they rely on the attacker being
able to coerce the client into creating many HTTPS connections (and
resending some secret token belonging to the user, along with
attacker-controlled data) each time, none of which is possible with IRC.
Lastly, since compression is no longer performed, this option will
result in leaking the lengths of messages transmitted to and from the
client. This option does reduce CPU utilization on Charybdis servers but
also increases bandwidth consumed.
The C standard does not allow constructing pointers beyond one past the end
of an array. Therefore, if size is an unsigned type (size_t), then
buf + size is never less than buf.
Clang on 32-bit took advantage of the undefined behaviour, causing
segfaults.
Lightly tested.
Note that these are not available in old versions of OpenSSL (like FreeBSD
9.x base OpenSSL), so allow them to be missing.
A side effect may be slightly higher CPU consumption and network traffic.
Without a session id context and if client certificates are used, OpenSSL
fails the handshake if an attempt is made to reuse an old session. Various
clients could not reconnect after a disconnection because of this.
See https://bugzilla.mozilla.org/show_bug.cgi?id=858394#c34 for a bug
report.
What is done here:
1. All the outdated configuration flag information has been removed and
replaced with the more current information.
2. Spellchecking has been done on all helpfiles and the actual errors
have been fixed.
Default values for default_floodcount and default_ident_timeout are set
in s_conf.c. Remove code that checks for missing values in ircd.c.
Additionally, reset default_ident_timeout to 5 if an invalid value (i.e.
0) is provided.
rb_crypt() was generating different SHA256 ($5$) hashes than glibc,
making hashes generated with charybdis unusable in ratbox and other
software, and vice versa.
There are IPv4 and IPv6 ranges reserved for documentation and example code;
use these to minimize the risk if someone accidentally uses an unmodified
example conf.
Add the flags (auth{} spoof, dynamic spoof) to struct Whowas and add a
show_ip_whowas().
Normal users now see IPs of unspoofed users, and remote opers can see IPs
behind dynamic spoofs. Also, general::hide_spoof_ips is now applied when
the IP is shown, not when the client exits.
For one, [draft-brocklesby-irc-isupport-02][1] already defines "ascii" as the
default value. According to section 2 ("Except as
explicitly stated in its definition, a parameter should not be sent
unless it changes this default value, or the default value is vague,
badly defined, or differs between IRC server implementations"), there is
no point in sending it.
For another, [version 03 of the same draft][2] removes CHARSET ("It was
found to be unworkable; a correct specification could not be devised to
represent its meaning across implementations."), and the token is not
present at all in [draft-hardy-irc-isupport-00][3].
[1]: https://tools.ietf.org/html/draft-brocklesby-irc-isupport-02#section-3.17
[2]: https://tools.ietf.org/html/draft-brocklesby-irc-isupport-03#section-4.8
[3]: https://tools.ietf.org/html/draft-hardy-irc-isupport-00
