Update init.go adding dnsValue Validation at interactive prompt

[jacostaperu]

Name of feature:

dnsValue validation to prevent panic when it is empty

Pain or issue this feature alleviates:

currently when calling step ca init it accept empty string for dnsValue causing panic later

Ô×£  certificates git:(master) STEPDEBUG=1 step ca init
Ô£ö Deployment Type: Standalone
What would you like to name your new PKI?
Ô£ö (e.g. Smallstep): SmallStep
What DNS names or IP addresses would you like to add to your new CA?     
Ô£ö (e.g. ca.smallstep.com[,1.1.1.1,etc.]):    <- leave it empty
What IP and port will your new CA bind to?
Ô£ö (e.g. :443 or 127.0.0.1:443): :8443
What would you like to name the CA's first provisioner?
Ô£ö (e.g. [email protected]): [email protected]
Choose a password for your CA keys and first provisioner.
Smallstep CLI/0.21.0 (linux/amd64)
Release Date: 2022-07-06T22:23:54Z

panic: runtime error: index out of range [0] with length 0 [recovered]
        panic: runtime error: index out of range [0] with length 0

goroutine 1 [running]:
main.panicHandler()
        ./main.go:139 +0x245
panic({0x12dec00, 0xc00003e1c8})
        runtime/panic.go:838 +0x207
github.com/smallstep/certificates/pki.New({{0x137b07c, 0x7}, {0x0, 0x0}, {0x0, 0x0}, 0x0, {0x0, 0x0}, {0x0, ...}, ...}, ...)
        github.com/smallstep/[email protected]/pki/pki.go:382 +0xfe5
github.com/smallstep/cli/command/ca.initAction(0xc00055c2c0)
        github.com/smallstep/cli/command/ca/init.go:563 +0x3419
github.com/urfave/cli.HandleAction({0x11bec80?, 0x1467900?}, 0x4?)
        github.com/urfave/[email protected]/app.go:522 +0x7f
github.com/urfave/cli.Command.Run({{0x1372454, 0x4}, {0x0, 0x0}, {0x0, 0x0, 0x0}, {0x13a51fc, 0x15}, {0x14122b5, ...}, ...}, ...)
        github.com/urfave/[email protected]/command.go:173 +0x652
github.com/urfave/cli.(*App).RunAsSubcommand(0xc0006ed880, 0xc00055c000)
        github.com/urfave/[email protected]/app.go:405 +0x91b
github.com/urfave/cli.Command.startApp({{0x137001e, 0x2}, {0x0, 0x0}, {0x0, 0x0, 0x0}, {0x13d6304, 0x2d}, {0x13eff37, ...}, ...}, ...)
        github.com/urfave/[email protected]/command.go:372 +0x6e7
github.com/urfave/cli.Command.Run({{0x137001e, 0x2}, {0x0, 0x0}, {0x0, 0x0, 0x0}, {0x13d6304, 0x2d}, {0x13eff37, ...}, ...}, ...)
        github.com/urfave/[email protected]/command.go:102 +0x808
github.com/urfave/cli.(*App).Run(0xc0006ed6c0, {0xc00003a180, 0x3, 0x3})
        github.com/urfave/[email protected]/app.go:277 +0x8a7
main.main()
        ./main.go:113 +0x611

Why is this important to the project (if not answered above):

I believe it will prevent code panics on that particular scenario.

Is there documentation on how to use this feature? If so, where?

In what environments or workflows is this feature supported?

In what environments or workflows is this feature explicitly NOT supported (if any)?

Supporting links/other PRs/issues:

💔Thank you!

[CLAassistant]

All committers have signed the CLA.

[hslatman]

Hey @jacostaperu, thank you for your report and your PR. I think a slightly different fix is needed, as the current patch may block multiple DNS names from being specified. I'll take a look soon.

[jacostaperu]

I am adding DNSListValidate function to ensure Multiple DNS lists are accepted, also validating they are valid according to RFC-952 and RFC-1123

[hslatman]

Hey @jacostaperu, I noticed your proposed change didn't allow space-separated values (only comma-separated) and also didn't include IPv6 addresses, so we can't merge this as is. I've created a PR with a different fix for this specific issue: #815. It doesn't rely on regexes and fits better with the existing validation for this input. I think the additional validation of the hostname you created might still be useful, but may have to go into https://github.com/smallstep/cli-utils/blob/main/ui/validators.go.

[hslatman]

Hey @jacostaperu, I'm closing this PR in favor of #815.