Comment 11 for bug 1560429

xenial verification

Confirmed the crash and squid's restart:
(...)
2017/08/03 13:40:17| pinger: ICMPv6 socket opened
2017/08/03 13:40:18 kid1| storeLateRelease: released 0 objects
(issued wget here)
2017/08/03 13:40:28 kid1| cannot change current directory to /var/spool/squid3: (2) No such file or directory
2017/08/03 13:40:28 kid1| Current Directory is /
2017/08/03 13:40:28 kid1| Starting Squid Cache version 3.5.12 for x86_64-pc-linux-gnu...
2017/08/03 13:40:28 kid1| Service Name: squid
2017/08/03 13:40:28 kid1| Process ID 5725 <----- new PID
2017/08/03 13:40:28 kid1| Process Roles: worker

wget gave up:
$ ftp_proxy=http://xenial-squid-passive-ftp-1560429.lxd:3128/ wget ftp://proftpd.lxd/readme.txt -O /dev/null -t1
--2017-08-03 10:40:22-- ftp://proftpd.lxd/readme.txt
Resolving xenial-squid-passive-ftp-1560429.lxd (xenial-squid-passive-ftp-1560429.lxd)... 10.0.100.226
Connecting to xenial-squid-passive-ftp-1560429.lxd (xenial-squid-passive-ftp-1560429.lxd)|10.0.100.226|:3128... connected.
Proxy request sent, awaiting response... No data received.
Giving up.

Installed squid from proposed:
(...)
Get:1 http://br.archive.ubuntu.com/ubuntu xenial-proposed/main amd64 squid amd64 3.5.12-1ubuntu7.4 [2,310 kB]
Get:2 http://br.archive.ubuntu.com/ubuntu xenial-proposed/main amd64 squid-common all 3.5.12-1ubuntu7.4 [176 kB]
Fetched 2,486 kB in 0s (11.7 MB/s)
(Reading database ... 27771 files and directories currently installed.)
Preparing to unpack .../squid_3.5.12-1ubuntu7.4_amd64.deb ...
Unpacking squid (3.5.12-1ubuntu7.4) over (3.5.12-1ubuntu7.3) ...
Preparing to unpack .../squid-common_3.5.12-1ubuntu7.4_all.deb ...
Unpacking squid-common (3.5.12-1ubuntu7.4) over (3.5.12-1ubuntu7.3) ...
Processing triggers for systemd (229-4ubuntu19) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for ufw (0.35-0ubuntu2) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up squid-common (3.5.12-1ubuntu7.4) ...
Setting up squid (3.5.12-1ubuntu7.4) ...
Skipping profile in /etc/apparmor.d/disable: usr.sbin.squid

wget now returns the expected 502 error:
$ ftp_proxy=http://xenial-squid-passive-ftp-1560429.lxd:3128/ wget ftp://proftpd.lxd/readme.txt -O /dev/null -t1
--2017-08-03 10:44:58-- ftp://proftpd.lxd/readme.txt
Resolving xenial-squid-passive-ftp-1560429.lxd (xenial-squid-passive-ftp-1560429.lxd)... 10.0.100.226
Connecting to xenial-squid-passive-ftp-1560429.lxd (xenial-squid-passive-ftp-1560429.lxd)|10.0.100.226|:3128... connected.
Proxy request sent, awaiting response... 502 Bad Gateway
2017-08-03 10:44:58 ERROR 502: Bad Gateway.

And squid just logs the attempt, with no crash:
==> /var/log/squid/access.log <==
1501767898.437 14 10.0.100.1 TCP_MISS/502 4356 GET ftp://proftpd.lxd/readme.txt - HIER_DIRECT/10.0.100.227 text/html

If I allow passive ftp on proftpd, then the file can be fetched:
$ ftp_proxy=http://xenial-squid-passive-ftp-1560429.lxd:3128/ wget ftp://proftpd.lxd/readme.txt -O /dev/null -t1
--2017-08-03 10:47:06-- ftp://proftpd.lxd/readme.txt
Resolving xenial-squid-passive-ftp-1560429.lxd (xenial-squid-passive-ftp-1560429.lxd)... 10.0.100.226
Connecting to xenial-squid-passive-ftp-1560429.lxd (xenial-squid-passive-ftp-1560429.lxd)|10.0.100.226|:3128... connected.
Proxy request sent, awaiting response... 200 Gatewaying
Length: unspecified [text/plain]
Saving to: ‘/dev/null’

/dev/null [ <=> ] 7 --.-KB/s in 0s

2017-08-03 10:47:06 (328 KB/s) - ‘/dev/null’ saved [7]

squid:
1501768026.900 16 10.0.100.1 TCP_MISS/200 422 GET ftp://proftpd.lxd/readme.txt - HIER_DIRECT/10.0.100.227 text/plain

proftpd (no 501 error for the EPSV command):
xenial-squid-passive-ftp-1560429.lxd UNKNOWN - [03/Aug/2017:13:47:06 +0000] "USER anonymous" 331 -
xenial-squid-passive-ftp-1560429.lxd UNKNOWN ftp [03/Aug/2017:13:47:06 +0000] "PASS (hidden)" 230 -
xenial-squid-passive-ftp-1560429.lxd UNKNOWN ftp [03/Aug/2017:13:47:06 +0000] "TYPE A" 200 -
xenial-squid-passive-ftp-1560429.lxd UNKNOWN ftp [03/Aug/2017:13:47:06 +0000] "MDTM readme.txt" 213 -
xenial-squid-passive-ftp-1560429.lxd UNKNOWN ftp [03/Aug/2017:13:47:06 +0000] "EPSV 1" 229 -
xenial-squid-passive-ftp-1560429.lxd UNKNOWN ftp [03/Aug/2017:13:47:06 +0000] "RETR readme.txt" 226 6
xenial-squid-passive-ftp-1560429.lxd UNKNOWN ftp [03/Aug/2017:13:47:06 +0000] "QUIT" 221 -