• src/sbbs3/mailsrvr.c

    From Rob Swindell (in GitKraken)@VERT to Git commit to main/sbbs/master on Tuesday, February 21, 2023 16:52:12
    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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  • From Rob Swindell (in GitKraken)@VERT to Git commit to main/sbbs/master on Monday, February 27, 2023 17:30:35
    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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  • From Rob Swindell (on Debian Linux)@VERT to Git commit to main/sbbs/master on Monday, February 27, 2023 17:32:16
    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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  • From Rob Swindell (in GitKraken)@VERT to Git commit to main/sbbs/master on Monday, February 27, 2023 18:33:56
    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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  • From Rob Swindell (on Debian Linux)@VERT to Git commit to main/sbbs/master on Thursday, March 02, 2023 01:11:32
    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 'events@mail.stubhub.com'
    'Eric S. Raymond (@esr)' vs 'gitlab@mg.gitlab.com'

    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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  • From Rob Swindell (on ChromeOS)@VERT to Git commit to main/sbbs/master on Monday, April 03, 2023 19:54:50
    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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  • From Rob Swindell (on Debian Linux)@VERT to Git commit to main/sbbs/master on Sunday, June 04, 2023 11:45:29
    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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  • From Rob Swindell (on ChromeOS)@VERT to Git commit to main/sbbs/master on Sunday, June 04, 2023 11:46:13
    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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  • From Rob Swindell (on Windows 11)@VERT to Git commit to main/sbbs/master on Saturday, September 28, 2024 01:22:04
    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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  • From Rob Swindell (on Windows 11)@VERT to Git commit to main/sbbs/master on Saturday, August 30, 2025 15:59:27
    https://gitlab.synchro.net/main/sbbs/-/commit/03404e9d93d482c358b0fc16
    Modified Files:
    src/sbbs3/mailsrvr.c
    Log Message:
    Use FCLOSE_OPEN_FILE macro to clean-up some redudant code

    No functional change.
    ---
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  • From Rob Swindell (on Windows 11)@VERT to Git commit to main/sbbs/master on Saturday, August 30, 2025 16:59:32
    https://gitlab.synchro.net/main/sbbs/-/commit/42167d4d30dd9ebaad0603a6
    Modified Files:
    src/sbbs3/mailsrvr.c
    Log Message:
    Don't archive SPAM-tagged messages received via SMTP for local users

    Follow up improvement for issue #969
    ---
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  • From Rob Swindell (on Debian Linux)@VERT to Git commit to main/sbbs/master on Sunday, August 31, 2025 21:42:24
    https://gitlab.synchro.net/main/sbbs/-/commit/f820805f0a5b552c677de048
    Modified Files:
    src/sbbs3/mailsrvr.c
    Log Message:
    Fix CID 584833
    ---
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  • From Rob Swindell (on Windows 11)@VERT to Git commit to main/sbbs/master on Monday, September 22, 2025 21:59:51
    https://gitlab.synchro.net/main/sbbs/-/commit/002a93442116fcec7a8940c7
    Modified Files:
    src/sbbs3/mailsrvr.c
    Log Message:
    Fix stack corruption in check_email_addr()

    MSVC build
    Run-Time Check Failure #2 - Stack around the variable 'name' was corrupted.

    Caused by "off by one" length calculations in calls to parse_mail_address() writing one extra byte to the nul-terminated 'name' string in extreme (nevarious?) situations.
    ---
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  • From Rob Swindell (on Windows 11)@VERT to Git commit to main/sbbs/master on Sunday, December 07, 2025 00:09:33
    https://gitlab.synchro.net/main/sbbs/-/commit/e689f9c4b727c8eeaca3a151
    Modified Files:
    src/sbbs3/mailsrvr.c
    Log Message:
    Ignore (but log an error) when DNSBL server returns IPv4 address != 127.0.0.x

    sbl.spamhaus.org returns 127.255.255.254 when attempting to query using a public/open resolver as Deuce discovered.

    See https://www.spamhaus.org/resource-hub/dnsbl/using-our-public-mirrors-check-your-return-codes-now/
    for details.
    ---
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