When my PowerShell script runs, it prompts the user for a password parameter. That password can contain any number of special characters like *\~;(%?.:@/ That password is then used as a parameter for a .exe command, but it is often incorrect due to some special characters not being escaped properly.
An example past password was $(?-.?-(. The only characters I needed to escape was '(', which I replaced with '`(' to make it work. However, that password is now expired. The new password is something like *\~;~(%?.:@/ *NOTE: these passwords have random numbers and letters mixed into them as well, but have been redacted.
The only characters in the new password NOT in the first are *\~;%:@/ Is there an easy way to escape all characters and just take any user input as it is? If not, would someone mind helping me escape these special characters?
param (
[Parameter(Mandatory=$true)][string]$password
)
The above code prefaces the script, causing the console to prompt for user input.
Invoke-Expression -Command "<path_to_exe> -install $user $password"
^this is the command that uses that password parameter
I have tried many other suggestions on Stack Overflow, Reddit, and other various coding forums/blogs and none have worked. Any help is much appreciated!
You're using Invoke-Expression to call an external program:
There's no reason to do that, and Invoke-Expression should generally be avoided: it causes quoting headaches (as in your case), but, more importantly, it can be a security risk and there are typically better solutions.
" chars. - see footnote [1] and this answer.If you instead invoke the external program directly - as any shell, including PowerShell is designed to do - your problem will likely go away:[1]
& <path_to_exe> -install $user $password
Note:
&, PowerShell's call operator, is only needed if your executable's path is quoted (e.g, "C:\Program Files\foo.exe") and/or is specified via a variable reference (e.g., $HOME\foo.exe); otherwise, you can invoke the executable as-is (e.g., to invoke cmd.exe, use something like cmd /c 'echo hi').
The above shows uses of individual variables as arguments; however, it is also possible to store multiple or all arguments in an array - see this answer.
Separately, if you do ever find yourself needing to escape any of the characters in a set of characters, use -replace with a character class, [...]:
Note: This is not necessary for passing arguments, neither to external programs, as shown above, nor to PowerShell commands; however, due to PowerShell's broken handling of " characters embedded in argument values passed to external programs, you may have to escape " characters (only), as \"[1].
PS> 'a*b\c~d;e(f%g?h.i:j@k/l' -replace '[*\\~;(%?.:@/]', '`$&'
a`*b`\c`~d`;e`(f`%g`?h`.i`:j`@k`/l # all chars. inside [...] were `-escaped
Note: Since \ has special meaning even inside a character class, it had to be escaped as \\ - all other chars. are used as-is.
For more information about the -replace operator, see this answer.
[1] There is one character that still causes problems: embedded ". For historical reasons, PowerShell does not properly pass embedded " correctly to external programs, and annoyingly requires manual \-escaping in Windows PowerShell and PowerShell (Core) versions up to v7.2.x - see this answer for details.
Applied to your solution:& <path_to_exe> -install $user ($password -replace '"', '\"')