dovecot - May 2020 - doveadm: extra lines?

Hello,

	I?m sending doveadm ?kick? commands to doveadm-server via the doveadm protocol.
When ?kick? sends back a NOTFOUND error, though, it?s sending back additional
output. strace shows:

write(3<UNIX:[3158354->3156665]>, "\t\tkick\tmyssltest\n",
17) = 17
...
read(3<UNIX:[3158354->3156665]>, "\n-NOTFOUND\n\n-\n", 8192)
= 14

Going by the protocol documentation
(https://wiki2.dovecot.org/Design/DoveadmProtocol), there appear to be 3 extra
bytes at the end of the server?s response: "\n-\n".

	Is this a bug in doveadm-server? Or am I misreading the protocol documentation?

	Thank you!

cheers,
-Felipe Gasper

I did a bit more digging, and the issue appears to manifest only when doveadm
sends back an error code.

Here is a ?user? and a ?kick?, both of which fail with error codes:
> echo -ne
'VERSION\tdoveadm-server\t1\t0\nD\tharry\tuser\nD\t\tkick\tharry\n' | nc
-U /var/run/dovecot/doveadm-server | xxd
0000000: 2b0a 0a2d 5553 4147 450a 0a2d 0a0a 2d4e  +..-USAGE..-..-N
0000010: 4f54 464f 554e 440a 0a2d 0a              OTFOUND..-.

Here is an ?auth?/?lookup? and a ?kick?, both of which fail, but only the ?kick?
gives back an error code:
> echo -ne
'VERSION\tdoveadm-server\t1\t0\nD\tharry\tauth\tlookup\nD\t\tkick\tharry\n'
| nc -U /var/run/dovecot/doveadm-server | xxd
0000000: 2b0a 0a2d 0a0a 2d4e 4f54 464f 554e 440a  +..-..-NOTFOUND.
0000010: 0a2d 0a                                  .-.

I?m seeing this with 2.3.9.3. I?m going to try to recompile with some debug
statements and see what I can suss out.

-FG

> On May 26, 2020, at 7:07 PM, Felipe Gasper <felipe at
felipegasper.com> wrote:
> 
> Hello,
> 
> 	I?m sending doveadm ?kick? commands to doveadm-server via the doveadm
protocol. When ?kick? sends back a NOTFOUND error, though, it?s sending back
additional output. strace shows:
> 
> write(3<UNIX:[3158354->3156665]>,
"\t\tkick\tmyssltest\n", 17) = 17
> ...
> read(3<UNIX:[3158354->3156665]>, "\n-NOTFOUND\n\n-\n",
8192) = 14
> 
> Going by the protocol documentation
(https://wiki2.dovecot.org/Design/DoveadmProtocol), there appear to be 3 extra
bytes at the end of the server?s response: "\n-\n".
> 
> 	Is this a bug in doveadm-server? Or am I misreading the protocol
documentation?
> 
> 	Thank you!
> 
> cheers,
> -Felipe Gasper

It looks like doveadm_cmd_server_post() prints its responses, then
client_handle_command() has this logic:

    if (doveadm_cmd_handle(conn, cmd_name, argc-2, args+2, &cctx) < 0)
        o_stream_nsend(conn->output, "\n-\n", 3);

? which will print the extra output.

It looks simple enough to fix, but would that break anything?

-FG

> On May 26, 2020, at 8:07 PM, Felipe Gasper <felipe at
felipegasper.com> wrote:
> 
> I did a bit more digging, and the issue appears to manifest only when
doveadm sends back an error code.
> 
> Here is a ?user? and a ?kick?, both of which fail with error codes:
> 
>> echo -ne
'VERSION\tdoveadm-server\t1\t0\nD\tharry\tuser\nD\t\tkick\tharry\n' | nc
-U /var/run/dovecot/doveadm-server | xxd
> 0000000: 2b0a 0a2d 5553 4147 450a 0a2d 0a0a 2d4e  +..-USAGE..-..-N
> 0000010: 4f54 464f 554e 440a 0a2d 0a              OTFOUND..-.
> 
> Here is an ?auth?/?lookup? and a ?kick?, both of which fail, but only the
?kick? gives back an error code:
> 
>> echo -ne
'VERSION\tdoveadm-server\t1\t0\nD\tharry\tauth\tlookup\nD\t\tkick\tharry\n'
| nc -U /var/run/dovecot/doveadm-server | xxd
> 0000000: 2b0a 0a2d 0a0a 2d4e 4f54 464f 554e 440a  +..-..-NOTFOUND.
> 0000010: 0a2d 0a                                  .-.
> 
> I?m seeing this with 2.3.9.3. I?m going to try to recompile with some debug
statements and see what I can suss out.
> 
> -FG
> 
> 
>> On May 26, 2020, at 7:07 PM, Felipe Gasper <felipe at
felipegasper.com> wrote:
>> 
>> Hello,
>> 
>> 	I?m sending doveadm ?kick? commands to doveadm-server via the doveadm
protocol. When ?kick? sends back a NOTFOUND error, though, it?s sending back
additional output. strace shows:
>> 
>> write(3<UNIX:[3158354->3156665]>,
"\t\tkick\tmyssltest\n", 17) = 17
>> ...
>> read(3<UNIX:[3158354->3156665]>,
"\n-NOTFOUND\n\n-\n", 8192) = 14
>> 
>> Going by the protocol documentation
(https://wiki2.dovecot.org/Design/DoveadmProtocol), there appear to be 3 extra
bytes at the end of the server?s response: "\n-\n".
>> 
>> 	Is this a bug in doveadm-server? Or am I misreading the protocol
documentation?
>> 
>> 	Thank you!
>> 
>> cheers,
>> -Felipe Gasper
>