A relay client could announce a huge websocket frame (or HTTP body via
"Content-Length") and dribble its payload, making WeeChat accumulate it
in a buffer that grew without limit, until all memory was exhausted. The
websocket frame path is reachable before authentication with the
"weechat" and "irc" protocols.
The announced websocket frame length and HTTP "Content-Length" are now
bounded by WEBSOCKET_FRAME_MAX_LENGTH and RELAY_HTTP_BODY_MAX_LENGTH: an
oversized websocket frame closes the connection, and an oversized body is
rejected.
A malicious or compromised IRC server could send data with no end-of-line
(or a flood of "005" messages), making WeeChat accumulate it in a buffer
that grew without limit, until all memory was exhausted.
The unterminated received message and the accumulated "005" (ISUPPORT)
data are now bounded by IRC_SERVER_RECV_MSG_MAX_LENGTH and
IRC_SERVER_ISUPPORT_MAX_LENGTH: extra data is ignored once the limit is
reached.
The IRC relay protocol's PASS handler compared the server password with
the client-supplied value using strcmp, leaking the password byte-by-byte
via response timing. This is the same class of bug fixed for the api and
weechat protocols, on a separate code path that did not go through
relay_auth_check_password_plain.
Extract the HMAC-then-constant-time-compare logic from
relay_auth_check_password_plain into relay_auth_password_equals, then
use it in both the plain-auth wrapper and the IRC PASS handler.
The relay authentication used non-constant-time comparisons (strcasecmp,
strcmp) to verify password hashes and plaintext passwords, allowing an
attacker to derive the expected hash byte-by-byte from response timing
and then authenticate without knowing the password.
- SHA/PBKDF2 hex hash comparisons: normalize the client-supplied hash to
uppercase and compare in constant time over the fixed expected length.
- Plaintext password comparison: HMAC-SHA256 both passwords with a fresh
per-call random key and compare the fixed-size MACs in constant time,
hiding both per-byte timing and the password length.
Add string_memcmp_constant_time helper in core, exposed via the plugin
API. Bump WEECHAT_PLUGIN_API_VERSION accordingly.
An authenticated relay client using the permessage-deflate websocket
extension could send a small compressed frame that decompresses to an
unbounded amount of data, exhausting all memory and crashing WeeChat.
The output buffer in relay_websocket_inflate is now capped to
WEBSOCKET_INFLATE_MAX_SIZE: frames decompressing beyond this limit are
rejected and the connection is closed.
This reverts commit e64ab3c675.
This was causing incorrect conversion of strings "0x..." to pointers on systems
like Solaris/illumos.
And as a side effect, buffers were sometimes empty in weechat relay clients
like glowing-bear.
For now the only supported flag is:
- "stop_on_error": stop execution of callbacks immediately after an
error (ie return code of callback is WEECHAT_RC_ERROR) and return this code
(by default execute all callbacks and return the last return code, or return
WEECHAT_RC_EAT immediately if a callback returns this)
Example:
hook_signal_send("[flags:stop_on_error]my_signal", WEECHAT_HOOK_SIGNAL_STRING, "test");
Before parsing IRC messages, they were almost all changed to convert IRC color
codes to WeeChat color codes, which caused some bugs when storing data like
account and real names (stored with WeeChat color codes instead of IRC colors).
Now the messages are parsed as-is, then the colors are converted only when
strings are displayed in a buffer by `weechat_printf()`.
Sébastien Helleu