pop3 retr responses too large lines - Fails with current python's poplib
Since December 2014, clients using the Python poplib library (getmail in my case) started to limit the line length of RETR and other command responses sent from the server to 2048 bytes: See https://bugs.python.org/issue16041 (Included at least in Python-2.7.9) Dovecot doesn't have line split in the POP3 module, so Python fails to retrieve messages with long lines. RFC 1939 says: " Responses in the POP3 consist of a status indicator and a keyword possibly followed by additional information. All responses are terminated by a CRLF pair. Responses may be up to 512 characters long, including the terminating CRLF. " I think dovecot-pop3 should split it's output in lines of at least 512 characters. Or at least it should have a "pop3_max_line_length" setting (like "imap_max_line_length"). Server side: # dovecot --version 2.2.13 Client side: # python --version Python 2.7.9 # getmail --version getmail 4.47.0 Temporary workaround (on client-side): --- poplib.py.orig 2015-04-08 18:46:48.280879211 -0300 +++ poplib.py 2015-04-08 18:26:01.288556028 -0300 @@ -36,7 +36,7 @@ # reading arbitrary length lines. RFC 1939 limits POP3 line length to # 512 characters, including CRLF. We have selected 2048 just to be on # the safe side. -_MAXLINE = 2048 +_MAXLINE = 2048*100 class POP3: Thanks in advance. -- Guillermo M. Narvaja Lambda Sistemas S.R.L. www.fierro-soft.com.ar - radiocut.fm Tel: (5411) 3220-1520 (rotativas) y 4857-6662 Cel: (5411) 15-6783-4435 Email: guillermo.narvaja@fierro-soft.com.ar MSN: guillermo_narvaja@hotmail.com Skype: guillermonarvaja Lavalleja 519 1er Piso - Ciudad de Buenos Aires - Argentina
On 09 Apr 2015, at 06:52, Guillermo M. Narvaja guillermo.narvaja@fierro.com.ar wrote:
Since December 2014, clients using the Python poplib library (getmail in my case) started to limit the line length of RETR and other command responses sent from the server to 2048 bytes:
See https://bugs.python.org/issue16041 (Included at least in Python-2.7.9)
Dovecot doesn't have line split in the POP3 module, so Python fails to retrieve messages with long lines.
RFC 1939 says: " Responses in the POP3 consist of a status indicator and a keyword possibly followed by additional information. All responses are terminated by a CRLF pair. Responses may be up to 512 characters long, including the terminating CRLF. "
I think dovecot-pop3 should split it's output in lines of at least 512 characters. Or at least it should have a "pop3_max_line_length" setting (like "imap_max_line_length").
Um. This is talking about POP3 responses themselves - not about the actual email message body. Dovecot's POP3 reponses are short always I think. The message body is sent exactly as it was originally saved. Changing this could break things like PGP/SMIME signing and so on.
El vie, 10-04-2015 a las 10:21 +0900, Timo Sirainen escribió:
On 09 Apr 2015, at 06:52, Guillermo M. Narvaja guillermo.narvaja@fierro.com.ar wrote:
Since December 2014, clients using the Python poplib library (getmail in my case) started to limit the line length of RETR and other command responses sent from the server to 2048 bytes:
See https://bugs.python.org/issue16041 (Included at least in Python-2.7.9)
Dovecot doesn't have line split in the POP3 module, so Python fails to retrieve messages with long lines.
RFC 1939 says: " Responses in the POP3 consist of a status indicator and a keyword possibly followed by additional information. All responses are terminated by a CRLF pair. Responses may be up to 512 characters long, including the terminating CRLF. "
I think dovecot-pop3 should split it's output in lines of at least 512 characters. Or at least it should have a "pop3_max_line_length" setting (like "imap_max_line_length").
Um. This is talking about POP3 responses themselves - not about the actual email message body. Dovecot's POP3 reponses are short always I think. The message body is sent exactly as it was originally saved. Changing this could break things like PGP/SMIME signing and so on.
So there is no way to break the lines without breaking the message?
Please note that if you are right, I should post a bug on the Python project.
You can see in this "traceforward" that Python's poplib will throw an error_proto exception if RETR returns lines longer than 2048 bytes:
https://hg.python.org/cpython/file/0db36098b908/Lib/poplib.py#l227 https://hg.python.org/cpython/file/0db36098b908/Lib/poplib.py#l165 https://hg.python.org/cpython/file/0db36098b908/Lib/poplib.py#l142 https://hg.python.org/cpython/file/0db36098b908/Lib/poplib.py#l370
def _getline(self):
line = ""
renewline = re.compile(r'.*?\n')
match = renewline.match(self.buffer)
while not match:
self._fillBuffer()if len(self.buffer) > _MAXLINE: # _MAXLINE=2048 raise error_proto('line too long')match = renewline.match(self.buffer) line = match.group(0) ...
-- Guillermo M. Narvaja Lambda Sistemas S.R.L. www.fierro-soft.com.ar - radiocut.fm Tel: (5411) 3220-1520 (rotativas) y 4857-6662 Cel: (5411) 15-6783-4435 Email: guillermo.narvaja@fierro-soft.com.ar MSN: guillermo_narvaja@hotmail.com Skype: guillermonarvaja Lavalleja 519 1er Piso - Ciudad de Buenos Aires - Argentina
On 10 Apr 2015, at 17:51, Guillermo M. Narvaja guillermo.narvaja@fierro.com.ar wrote:
El vie, 10-04-2015 a las 10:21 +0900, Timo Sirainen escribió:
On 09 Apr 2015, at 06:52, Guillermo M. Narvaja guillermo.narvaja@fierro.com.ar wrote:
Since December 2014, clients using the Python poplib library (getmail in my case) started to limit the line length of RETR and other command responses sent from the server to 2048 bytes:
See https://bugs.python.org/issue16041 (Included at least in Python-2.7.9)
Dovecot doesn't have line split in the POP3 module, so Python fails to retrieve messages with long lines.
RFC 1939 says: " Responses in the POP3 consist of a status indicator and a keyword possibly followed by additional information. All responses are terminated by a CRLF pair. Responses may be up to 512 characters long, including the terminating CRLF. "
I think dovecot-pop3 should split it's output in lines of at least 512 characters. Or at least it should have a "pop3_max_line_length" setting (like "imap_max_line_length").
Um. This is talking about POP3 responses themselves - not about the actual email message body. Dovecot's POP3 reponses are short always I think. The message body is sent exactly as it was originally saved. Changing this could break things like PGP/SMIME signing and so on.
So there is no way to break the lines without breaking the message?
Right.
Please note that if you are right, I should post a bug on the Python project.
Yes. They are crazy if they think their behavior would work with any POP3 server. I think they have simply misunderstood the RFC.
El vie, 10-04-2015 a las 17:59 +0300, Timo Sirainen escribió:
On 10 Apr 2015, at 17:51, Guillermo M. Narvaja guillermo.narvaja@fierro.com.ar wrote:
El vie, 10-04-2015 a las 10:21 +0900, Timo Sirainen escribió:
On 09 Apr 2015, at 06:52, Guillermo M. Narvaja guillermo.narvaja@fierro.com.ar wrote:
Since December 2014, clients using the Python poplib library (getmail in my case) started to limit the line length of RETR and other command responses sent from the server to 2048 bytes:
See https://bugs.python.org/issue16041 (Included at least in Python-2.7.9)
Dovecot doesn't have line split in the POP3 module, so Python fails to retrieve messages with long lines.
RFC 1939 says: " Responses in the POP3 consist of a status indicator and a keyword possibly followed by additional information. All responses are terminated by a CRLF pair. Responses may be up to 512 characters long, including the terminating CRLF. "
I think dovecot-pop3 should split it's output in lines of at least 512 characters. Or at least it should have a "pop3_max_line_length" setting (like "imap_max_line_length").
Um. This is talking about POP3 responses themselves - not about the actual email message body. Dovecot's POP3 reponses are short always I think. The message body is sent exactly as it was originally saved. Changing this could break things like PGP/SMIME signing and so on.
So there is no way to break the lines without breaking the message?
Right.
Please note that if you are right, I should post a bug on the Python project.
Yes. They are crazy if they think their behavior would work with any POP3 server. I think they have simply misunderstood the RFC.
Ok, I posted an issue on the Python's issue tracker:
http://bugs.python.org/issue23906
I expect this can be fixed in either of the sides.
-- Guillermo M. Narvaja Lambda Sistemas S.R.L. www.fierro-soft.com.ar - radiocut.fm Tel: (5411) 3220-1520 (rotativas) y 4857-6662 Cel: (5411) 15-6783-4435 Email: guillermo.narvaja@fierro-soft.com.ar MSN: guillermo_narvaja@hotmail.com Skype: guillermonarvaja Lavalleja 519 1er Piso - Ciudad de Buenos Aires - Argentina
participants (2)
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Guillermo M. Narvaja
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Timo Sirainen