https://gitlab.synchro.net/main/sbbs/-/commit/ce90be9ea7fcacddfd60628c
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Fix corrupted RFC822 msg headers when a header field was > 1024 chars

When sending an SMB message header via SMTP or POP3, some header fields (lines) could potentially be longer than 1024 and yet sockprintf() was limited to sending 1024 bytes (actually 1022 plus CRLF). This could result in some messages not being sent correctly: header field truncated, not CRLR-terminated, and notably resulting in MIME message contents not being decoded properly in a message viewer/reader. Example (Content-Type is part of the previous header field/line):
x-ms-exchange-antispam-messagedata-0:
=?us-ascii?Q?cm9T1Q9G65VC/lKTTqhODKhy5lHT2y6WWMb/WyvJ+EeGEwYmY7ILhzE3yfNM?=
=?us-ascii?Q?KeFWN9T/PqHBya1plKf/sHgaw0iRmI7Hq+u9Dp4bG8OqdniKQlK+Aa27oXMd?=
=?us-ascii?Q?Hly6OEYaSu7jbhGGY89LF0gyRVqquqxkaMfpKvG+h4cQnnu4Tl8YAKeE39a2?=
=?us-ascii?Q?lHW3372ulmb9jvvZU72J2RtZYkuoIr+Wsqhfyuj39wTZ/+C4qKCsYrmTxrki?=
=?us-ascii?Q?fBZ4gMPzWkrcWAr7zPcXBg8bphJJB8VJFUjQyksA3EG4dtH8+TZeEcNNBmHf?=
=?us-ascii?Q?oCGnV9wHr9HszzrSkkZ2GGyh3QZLHAVDNe7wDXSy7HJttZugf9kNqKGeaYQL?=
=?us-ascii?Q?TpljH1aHPe7MiSP9Dmp/xHQ/DWQOZDx5guNS+iMciMt5p5ad+SkQye0hWRhd?=
=?us-ascii?Q?usHvpllclzIee6lxJ0VSPAzHGlAOhtOolrHdDB2ODjvkEzU7L2Fj2f5x7p9q?=
=?us-ascii?Q?9d6sUgSz7vZVx8yyR3KPq3jIX0QUnl0xr2Mix9xcmMNcg0yFLPcznqBdLVa8?=
=?us-ascii?Q?IC7j0+8oy4BjYxr8Z3elxMC2JKq13gPYgR95cwm6hMDiZbMB4EW/J1uJhD/I?=
=?us-ascii?Q?RIIqTZ+Ywt8nKOfXj6/a9Aauf0wN71QKKA+in7KY9oksIhkUGvWOrtJwkVDL?=
=?us-ascii?Q?Q2UFrBBJyQHJgumj5Y+bG8FDk/55IfyV9XYEcsdLL4bCF+HX4QPHZCw4P+li?=
=?us-ascii?Q?bRvN+UxOO8hgXVkgB1q8mNJ62yQuaj0AContent-Type: multipart/alternative;
boundary="_000_SN6PR07MB454477F4C32C66D48BA0B02187A09SN6PR07MB4544namp_"

Solved by using asprintf() instead of snprintf() for dynamic string formatting and allocation in one go. Using realloc() to expand the buffer for the appended/required CRLF.

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https://gitlab.synchro.net/main/sbbs/-/commit/b19288125fb9470836cf50af
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Reject SMTP session from any client that sends illegally-long lines

Log a warning message and send a "500 Line too long" before disconnecting any SMTP client that sends lines > 998 characters in length. Technically, we can handle lines up to 1023 characters, but then we could get out of sync with the client if it sends exactly 1023 chars and then a new-line char (which we would interpret as a blank line, separating the message header and body) - so just punt the client who doesn't obey the rules of the protocol.

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https://gitlab.synchro.net/main/sbbs/-/commit/7611f92f4057dae1dd11878a
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Resolve new GCC printf-format warning in new log message text

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https://gitlab.synchro.net/main/sbbs/-/commit/4c6cc08369da690cae967264
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Handle illegally-long received SMTP lines better

SMTP commands have a shorter limit (510 versus 998) and the body text line limit needed to account for dot-stuffing.

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https://gitlab.synchro.net/main/sbbs/-/commit/2852540e7b592e32195f03b8
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Fix false FORGED mail header 'FROM' field detection/rejection

Pretty much any From field that contains an '@' in the username portion
was subject to comparison to the full email address, but clearly some of
these rejected emails were not forge attempts:

'Chris @ StubHub' vs '[email protected]'
'Eric S. Raymond (@esr)' vs '[email protected]'

Fixed by requiring that the sender name is actually a well-formed Internet email address using smb_netaddr_type(), which was also recently improved to
be more accurate.

Unrelated change: include reverse-path (email address for bounces) in ILLEGALLY-LONG body and header line log messages (usually SPAM from what
I can tell).

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https://gitlab.synchro.net/main/sbbs/-/commit/0f4325eece0e65872ce008c9
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Publish SMTP[S] user authentications to the action/login/PROTOCOL topic

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https://gitlab.synchro.net/main/sbbs/-/commit/fb11866c6dadbd6a8d861b77
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Fix potential NULL pointer deref in rblchk(), observed via segfault lately

I'm not sure why this one only started popping up now, but h_addr_list is a NULL-terminated list and it makes perfect sense that the first entry could
be the NULL-terminator.

gethostbyname is obsolete/deprecated and we should address that in a separate commit.

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https://gitlab.synchro.net/main/sbbs/-/commit/1f7cd77aef826d3256ae4e2e
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Check return value of fread()

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https://gitlab.synchro.net/main/sbbs/-/commit/f689169a82124f18d5e4ccd9
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Close socket after logging the "REFUSED SESSION from blacklisted server" msg

Fixes issue #670

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https://gitlab.synchro.net/main/sbbs/-/commit/a35cb08fb0a5f69bbe11f010
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Better resource (e.g. client thread) management

My mail server was suddenly and inexplicably creating thousands of SMTPS
client threads, each with a unique remote IP address, and each eventually failing with the rather obscure log message (from cryptlib):
dbg 'Cannot read item from object' (-41) setting session active

Eventually (after not long, really), the server would run out of resources
and fail in weird and wonderful ways (can't malloc, can't create JS runtime
or context, etc.). The max_clients limit (100, as I have it set) wasn't being effectively-imposed on SMTPS connections.

The root-cause: the active_clients (counter) wasn't incremented until *after* the cryptlib/TLS setup for SMTPS connections and SMTPS/TLS connections can
take a long time to fail, resulting in a vulnerability to an effective denial of service attack.

Raise the minimum severity of all cryptlib/TLS log messages from Debug to
Info.

Create wrappers for smtp_thread() [now smtp_client_thread()] and pop3_thread [now pop3_client_thread()] that handle basic resource management (thread counters, active client counters, the client socket).

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https://gitlab.synchro.net/main/sbbs/-/commit/7d9c8624f7d9c5e0fd1cd5a7
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Fix extra decrement of active_clients (added in previous commit)

And fix some use of CRYPT_UNUSED instead of cryptlib session ID.

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https://gitlab.synchro.net/main/sbbs/-/commit/f43e852a170d27afdf6e33a4
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
SMTP mail server wasn't RFC 4954 compliant for "AUTH PLAIN" logins

The base64-encoded credentials can either be supplied with the AUTH PLAIN command or in response to a 334 server-challenge. We only supported the
former form and logged a warning ("Missing AUTH PLAIN argument") when we received the latter. No warning is logged now and the appropriate server-challege is sent and the response accepted and base64-decoded and
parsed as before.

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https://gitlab.synchro.net/main/sbbs/-/commit/952a25f17aa96355e4c92e95
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
More commonization of "CLIENT BLOCKED" log messages

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https://gitlab.synchro.net/main/sbbs/-/commit/62b866c243d9a8201c55b6fa
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
If cryptInit() fails, just disable TLS support

But continue initializing/running for other non-TLS protocol support.

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https://gitlab.synchro.net/main/sbbs/-/commit/fa5ae01239d3488112dae489
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Some more printf formats... mostly off_t but also a size_t and an time_t

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https://gitlab.synchro.net/main/sbbs/-/commit/76055e3d35e795f4ceeefb0e
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Add missing header?

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https://gitlab.synchro.net/main/sbbs/-/commit/f44997570fb796b34f99285f
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Aha! XP_PRIsize_t is a *size*, not a *type*.

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https://gitlab.synchro.net/main/sbbs/-/commit/aaa82ca4c9a5aac286603272
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Oh damn, this is an off_t + size_t + 1... talk about the wild west of types!

Both long long and long are reasonable for some mixes of platforms.

Just punt, cast the whole thing to int64_t, and forget about it.

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https://gitlab.synchro.net/main/sbbs/-/commit/5cc3767eb1d56bb0db294f86
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Use fnopen() for auto-retry when opening dnsbl_exempt.cfg for append

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https://gitlab.synchro.net/main/sbbs/-/commit/5564eb67e84e55e8a6dcbb0e
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
MIME-encode words that contain non-ASCII values in text header fields

(e.g. to, from, subject) ... when transmitting to other hosts (e.g. POP3 clients or other SMTP hosts).

For messages that contain CP437 or UTF-8 chars in these fields and were *not* imported into the BBS via SMTP or POP3, these header fields would be transmitted to other hosts with the raw CP437 or UTF-8 chars, thus violating POP3 and SMTP protocols and likely resulting in garbage displayed in message readers.

The fix is to encode (using MIME "encoded words", per RFC 2407) where necessary.

Since moderm mail clients (e.g. Thunderbird) don't see to support CP437
charset in MIME encoded header fields, always translate to UTF-8 first.

We probably should be translating message body text to UTF-8 as well, for maximum compatibilty with modern mail readers, but this commit doesn't address body text issues with CP437-encoded content. That'll come later.

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https://gitlab.synchro.net/main/sbbs/-/commit/42e9eb8bf7c0d7f338b46d1c
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Allow email.can to contain email sender/recipient *names* as well as addresses

Allow filtering/blocking email based on the name portion of email header fields.

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https://gitlab.synchro.net/main/sbbs/-/commit/e6d8053f3457d19d0e456ddb
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Report bigger "size of message" in POP3 LIST response

For messages that have no body, we'd report 0. But RFC 1939 says this value
is supposed to be "the exact size of the message in octets" <sigh>. This
would include header fields, so while we can't know the exact RFC822 size, adding the msg's hdr.length to these values gives size > 0 for messages
with no body text and this enables the Apple iPhone Mail app to download
the message (fixing issue #822).

Part two of this fix is to provide a blank line of message text when there
is none. This changes the message displayed in the iPhone Mail app from:

"This message cannot be displayed because of the way it is formatted.
Ask the sender to send it again using a different format or email program.

text/plain"

to (the much nicer):
"This message has no content".

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https://gitlab.synchro.net/main/sbbs/-/commit/bb3485a9c4e2c36a07aaf512
Modified Files:
src/sbbs3/mailsrvr.c
Log Message:
Include the size of the message headers in the POP3 STAT response too

I suppose if we only had messages with no body text, this value could be 0
(not accounting for any headers) and thus throw a client off.

So consider this as part of the fix for issue #822.

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