[build_templates] [hostcfgd] Keep containers hostname up to date

[msosyak]

- What I did
Implemented logic to keep containers hostname up to date

- How I did it

• Added updateHostName function to docker_image_ctl.j2
• Added hostname specification on container creating step
• Added listener for hostname changes in hostcfgd which call updateHostName for all running containers if an appropriate script(generated from docker_image_ctl.j2) exist in /usr/bin

- How to verify it
Change hostname in config_db.json
Load new configuration
Check hostname in containers

- Description for the changelog
Added logic to keep containers hostname up to date

@akokhan @pyadvichuk @vsenchyshyn @qiluo-msft @jleveque @lguohan

[msftclas]

All CLA requirements met.

[qiluo-msft]

$HOSTNAME [](start = 19, length = 9)

Possible input injection #Closed

[qiluo-msft]

Still possible. For example:
sonichost"; rm -rf /; echo "

---

In reply to: 286279985 [](ancestors = 286279985)

[msosyak]

Bash did not process metacharacters from variables only metacharacters directly present in a script or interpreter line.
It is easy to check by the next commands:

print_args() {
while (( "$#" )); do 
  echo $1 
  shift 
done
}
X="hostName"
Y='sonic"; echo injection; echo "'
print_args --hostname "$X" --name cname
#output
>>> --hostname
hostName
--name
cname

print_args --hostname "$Y" --name cname
#output
>>> --hostname
sonic"; echo injection; echo "
--name
cname

I thought that CVE-2016-0634 can be exploited there. But sonic use bash 4.4

So, for any case added validation for allowed characters in a hostname. #Closed

[msosyak]

@qiluo-msft Could we close this conversation?

[qiluo-msft]

Nice comments! Really appreciate the clarification and reference.

---

In reply to: 286898693 [](ancestors = 286898693)

[qiluo-msft]

As comments

[myronsosyak]

Review comments fixed

[mykolaf]

Please use a standard commit message format:

[component/folder touched]: Description intent of your changes

[List of changes]

Signed-off-by: Your Name your@email.com

e.g. [image config] Keep containers hostname up to date

[jleveque]

Please fix typo in log message per comment above.

[akokhan]

@jleveque , @lguohan ,
as I see, all review comments are resolved now. Is there anything else that blocks us from merging this PR?

[jleveque]

Retest this please