> On 11 April 2019 11:02 Laura Smith via dovecot <[email protected]> wrote: > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > On Thursday, April 11, 2019 12:55 AM, John Fawcett via dovecot > <[email protected]> wrote: > > > On 11/04/2019 00:51, Laura Smith via dovecot wrote: > > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > On Wednesday, April 10, 2019 11:48 PM, John Fawcett via dovecot > > > [email protected] wrote: > > > > > > > On 11/04/2019 00:18, Laura Smith via dovecot wrote: > > > > > > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > > > On Wednesday, April 10, 2019 10:24 PM, Aki Tuomi > > > > > [email protected] wrote: > > > > > > > > > > > > On 10 April 2019 23:56 Laura Smith via dovecot < > > > > > > > [email protected]> wrote: > > > > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > > > > > On Wednesday, April 10, 2019 9:14 PM, Aki Tuomi < > > > > > > > [email protected]> wrote: > > > > > > > > > > > > > > > > On 10 April 2019 23:13 Laura Smith via dovecot > > > > > > > > > [email protected] wrote: > > > > > > > > > Sent with ProtonMail Secure Email. > > > > > > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > > > > > > > On Wednesday, April 10, 2019 8:20 PM, Aki Tuomi > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > On 10 April 2019 22:13 Laura Smith via dovecot > > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > On Wednesday, April 10, 2019 7:57 PM, Aki Tuomi > > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > On 10 April 2019 21:26 Laura Smith via dovecot > > > > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > ========================================================================== > > > > > > > > > > > > > dsync( [email protected]): Error: > > > > > > > > > > > > > imapc(foobar.example.com:993): > > > > > > > > > > > > > dns_lookup(foobar.example.com) failed: > > > > > > > > > > > > > read(/var/run/dovecot/dns-client) failed: > > > > > > > > > > > > > read(size=512) failed: Connection reset by peer > > > > > > > > > > > > > This is dovecot's internal dns-client, and something > > > > > > > > > > > > > goes wrong when talking to the service. > > > > > > > > > > > > > dsync( [email protected]): Error: Failed to > > > > > > > > > > > > > initialize user: imapc: Login to foobar.example.com > > > > > > > > > > > > > failed: Disconnected from server > > > > > > > > > > > > > This is btw dsync service, not imap service. > > > > > > > > > > > > > =============================================================================================================================================================================================================================================================================================================================================================================================================================================================================== > > > > > > > > > > > > > Initially I thought "oh no, not another AppArmor > > > > > > > > > > > > > block". > > > > > > > > > > > > > But then surely the second message would not appear > > > > > > > > > > > > > if the DNS lookup was not successful ? > > > > > > > > > > > > > Also "dig foobar.example.com" works fine. > > > > > > > > > > > > > How should I be troubleshooting this ? And if it is > > > > > > > > > > > > > still likely to be AppArmor, what is calling it ? > > > > > > > > > > > > > "doveadm" itself or something else ? What does > > > > > > > > > > > > > "/var/run/dovecot/dns-client" do and why doesn't > > > > > > > > > > > > > dovecot use standard OS calls like everyone else ? > > > > > > > > > > > > > Because the "standard OS call" is blocking and we > > > > > > > > > > > > > would prefer it to not block everything else. > > > > > > > > > > > > > So many questions ! > > > > > > > > > > > > > Aki > > > > > > > > > > > > > Thanks for your reply, but both those message are > > > > > > > > > > > > > generated from a simple : > > > > > > > > > > > > > doveadm -v -o mail_fsync=never backup -R -u > > > > > > > > > > > > > [email protected] imapc: > > > > > > > > > > > > > So I don't know what you mean about dsync service > > > > > > > > > > > > > failing ? Surely the DNS lookup succeeded if the > > > > > > > > > > > > > 'dsync service' failed due to remote disconnect ? > > > > > > > > > > > > > I'm still none the wiser as to where to start looking > > > > > > > > > > > > > for troubleshoting ? > > > > > > > > > > > > > Did you check dovecot logs? Maybe there is something > > > > > > > > > > > > > useful? > > > > > > > > > > > > > Aki > > > > > > > > > > > > > Only the same old cryptic message about dns-client ? > > > > > > > > > > > > > master: Fatal: execv(/usr/lib/dovecot/dns-client) > > > > > > > > > > > > > failed: Permission denied > > > > > > > > > > > > > Something prevents executing the dns-client binary. > > > > > > > > > > > > > master: Error: service(dns_client): command startup > > > > > > > > > > > > > failed, throttling for 16 secs > > > > > > > > > > > > > dns_client: Fatal: master: service(dns_client): child > > > > > > > > > > > > > 14293 returned error 84 (exec() failed) > > > > > > > > > > > > > Aki > > > > > > > > > > > > > Yes but is it being called by doveadm directly or by > > > > > > > > > > > > > some other dovecot program ? If I'm going to have to > > > > > > > > > > > > > go down the AppArmor route, then I would prefer if > > > > > > > > > > > > > you told me what was calling it instead of me having > > > > > > > > > > > > > to un-necessarily spend time doing straces ! > > > > > > > > > > > > > Also, should I be able to call dns-client directly > > > > > > > > > > > > > myself ? (or is there a way to do so to enable > > > > > > > > > > > > > testing ? > > > > > > > > > > > > > It is started by dovecot's master process when you > > > > > > > > > > > > > connect to dns-client unix socket. You can try > > > > > > > > > > > > > socat stdio unix-connect:/var/run/dovecot/dns-client > > > > > > > > > > > > > I thought apparmor tells when something is blocked > > > > > > > > > > > > > into kernel log? have you checked dmesg? > > > > > > > > > > > > Apologies for your frustration. > > > > > > > > > > Yeah nothing in dmesg. I'm still hunting around to find some log > > > > > somewhere but so far silence. > > > > > "socat stdio unix-connect:/var/run/dovecot/dns-client" runs but > > > > > returns nothing. Is that expected ? > > > > > When you say "dovecot's master process", so doveadm sync talks to > > > > > the master process ? So in terms of apparmor I would therefore be > > > > > looking at /usr/sbin/dovecot ? If that's the case, the relevant > > > > > apparmor permisssions are already provided : > > > > > /{,var/}run/dovecot/ rw, > > > > > /{,var/}run/dovecot/** rw, > > > > > Laura > > > > > > > > Do the above apparmor settings give permission to dovecot to execute > > > > /usr/lib/dovecot/dns-client, assuming that the user under which dovecot > > > > is running already has file system permissions to do that? > > > > John > > > > > > John, > > > Here's the definitive answer to your question (and anyone else thinking > > > of pointing the finger at apparmor): > > > foo:/home/foo # sudo systemctl stop apparmor > > > foo:/home/foo # doveadm -v -o mail_fsync=never backup -R -u > > > [email protected] imapc: > > > dsync([email protected]): Error: imapc(foobar.example.com:993): > > > dns_lookup(foobar.example.com) failed: DNS lookup timed out > > > dsync([email protected]): Error: Failed to initialize user: imapc: Login > > > to foobar.example.com failed: Disconnected from server > > > So. Can we move on from the "blame apparmor" ? ;-) > > > > Laura > > > > I'd suggest doing the test with a restart of dovecot in between stopping > > apparmor and running the doveadm command. Check your logs to see if > > there is no longer any message generated about not being able to execv > > /usr/lib/dovecot/dns-client. > > > > foo:/home/foo # sudo systemctl stop apparmor > > foo:/home/foo # sudo systemctl restart dovecot > > foo:/home/foo # doveadm -v -o mail_fsync=never backup -R -u > > [email protected] imapc: > > > > John > > > Same again.... > > failed: read(/var/run/dovecot/dns-client) failed: read(size=512) failed: > Connection reset by peer
And your logs probably indicate that same Fatal error that the service cannot be started? Wonder if this is caused by systemd? Can you try also systemctl stop dovecot dovecot -F then try socat and see if it works? Aki
