Jenkins pipeline script issue with wget and variables in URL - jenkins

Question

I have checked many suggestions regarding the issue, but didn't find a suitable solution.
Initially my pipeline code was working fine but with a Jenkins security warning The following steps that have been detected may have insecure interpolation of sensitive variables. sh: [pass, user]
My code is as below:
withCredentials([usernamePassword(credentialsId: 'Jenkins-Nexus-tech', passwordVariable: 'pass', usernameVariable: 'user')]){
sh "wget --user=$user --password=$pass 'https://nexus.mycompany.io/repository/updated-maven-releases/com/mycompany/project/authorization-server/${params.AuthorizationServerVersion}/authorization-server-${params.AuthorizationServerVersion}.war' "
}
Warning:
[Pipeline] sh
Warning: A secret was passed to "sh" using Groovy String interpolation, which is insecure.
Affected argument(s) used the following variable(s): [pass, user]
See https://jenkins.io/redirect/groovy-string-interpolation for details.
To avoid the Jenkins security warning as suggested in https://www.jenkins.io/doc/book/pipeline/jenkinsfile/#interpolation-of-sensitive-environment-variables , I have modified my code as below. But with different permutation and combination of single and double quotes it is not working. It is throwing Bad substitution error:
withCredentials([usernamePassword(credentialsId: 'Jenkins-Nexus-tech', passwordVariable: 'pass', usernameVariable: 'user')]){
sh 'wget --user=$user --password=$pass \"https://nexus.mycompany.io/repository/updated-maven-releases/com/mycompany/project/authorization-server/${params.AuthorizationServerVersion}/authorization-server-${params.AuthorizationServerVersion}.war\" '
}
I have tried with 3 single quotes. with this I am not getting the warning but it is unable to substitute the variables in the wget URL:
withCredentials([usernamePassword(credentialsId: 'Jenkins-Nexus-tech', passwordVariable: 'pass', usernameVariable: 'user')]){
sh '''wget --user=$user --password=$pass 'https://nexus.mycompany.io/repository/updated-maven-releases/com/mycompany/project/authorization-server/${params.AuthorizationServerVersion}/authorization-server-${params.AuthorizationServerVersion}.war' '''
}
Error is as below as it can't substitute the values of the variable
[Pipeline] sh
+ wget --user=**** --password=**** https://nexus.mycompany.io/repository/updated-maven-releases/com/mycompany/project/authorization-server/${params.AuthorizationServerVersion}/authorization-server-${params.AuthorizationServerVersion}.war
HTTP request sent, awaiting response... 404 com/mycompany/project/authorization-server/${params.AuthorizationServerVersion}/authorization-server-${params.AuthorizationServerVersion}.war
ERROR 404: com/mycompany/project/authorization-server/${params.AuthorizationServerVersion}/authorization-server-${params.AuthorizationServerVersion}.war.
It would be really great if someone can assist here.

Answer 1

The suggestion outlined in the page you mention suggests you do not use Groovy string interpolation to pass sensitive data to sh steps. The suggestion is to let the sh script instead get the values from the environment.
However, in your case you still need the value held in the params.AuthorizationServerVersion in your sh step.
Groovy string interpolation is only used when the string is within double quotes. String interpolation is turned off when the string is in single quotes.
When a string is in double quotes, you can escape $s using a backslash. This will prevent inserting the contents of a variable into the string when you don't want this to occur.
What you can do, then, is use double quotes, escape the $s on the variables you want to read from the environment, and leave the $s un-escaped on the variables you want to access directly from your Groovy code.
An example, using the withCredentials plugin:
withCredentials([string(credentialsId: 'mytoken', variable: 'THE_TOKEN')]) {
sh "some_command --that-uses \$THE_TOKEN --as-an-environment-variable --and-also-uses $params.A_PARAMETER"
}
Here, the token is injected into the environment as a secret, and is used in the sh script by escaping the $. This means the actual Unix shell (bash, zsh, or whatever) will get the literal $ and expand it as specified by that shell language.
The $ for $params.A_PARAMETER is not escaped, and is within double quotes, so Groovy will perform string interpolation and replace $params.A_PARAMETER with the value of the parameter at runtime as the string is constructed in memory, before the string is passed as an argument to the sh step.
In your specific case, this is what you can use (within your withCredentials block, of course):
sh "wget --user=\$user --password=\$pass 'https://nexus.mycompany.io/repository/updated-maven-releases/com/mycompany/project/authorization-server/${params.AuthorizationServerVersion}/authorization-server-${params.AuthorizationServerVersion}.war'"
Note that the $ on $user and $pass are escaped, but the $ on ${params.AuthorizationServerVersion} is not escaped.