Private/Get-CsrDetails.ps1
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function Get-CsrDetails { [CmdletBinding()] param( [Parameter(Mandatory,Position=0)] [Alias('CSRString')] [string]$CSRPath ) # Given a PEM formatted CSR file path or raw string value, we need to parse the # request and return a hashtable with the following parsed details to the caller: # # Domain : The collection of FQDNs found in the CN and/or SAN attributes # KeyLength : The key length value using our Posh-ACME nomeclature # OCSPMustStaple : Boolean indicating whether the OCSP Must Staple flag is set # Base64Url : The Base64Url encoded bytes of the raw request # PemLines : The original lines from the file/string PEM request content # We're going to try to allow for CSRs being passed directly as a string value # in addition to a filesystem path. Since the BC PemReader currently requires # explicit BEGIN/END header and footer, we're going to assume that anything # missing them is a file path. if ($CSRPath -cnotlike '*CERTIFICATE REQUEST*') { Write-Debug "CSRPath didn't match CERTIFICATE REQUEST" # normalize the CSR path and make sure it exists $CSRPath = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($CSRPath) if (-not (Test-Path $CSRPath -PathType Leaf)) { throw "CSR file not found at $CSRPath" } $importParams = @{ InputFile = $CSRPath } $details = @{ PemLines = Get-Content $CSRPath } } else { $importParams = @{ InputString = $CSRPath } $details = @{ PemLines = $CSRPath.Trim() -split "(?:`r)?`n" } } # parse the CSR into a [Org.BouncyCastle.Asn1.Pkcs.CertificationRequest] Write-Debug "Attempting to import CSR pem" $csr = Import-Pem @importParams if ($csr -isnot [Org.BouncyCastle.Pkcs.Pkcs10CertificationRequest]) { throw "Specified CSR was unable to be parsed as a certificate request." } $details.Base64Url = ConvertTo-Base64Url $csr.GetEncoded() # determine the KeyLength $pubKey = $csr.GetPublicKey() if ($pubKey -is [Org.BouncyCastle.Crypto.Parameters.RsaKeyParameters]) { # RSA key, so KeyLength is just the bit length of the Modulus $details.KeyLength = $pubKey.Modulus.BitLength.ToString() if (-not (Test-ValidKeyLength $details.KeyLength)) { throw "RSA key length from CSR is out of the supported range. ($($details.KeyLength))" } } elseif ($pubKey -is [Org.BouncyCastle.Crypto.Parameters.ECPublicKeyParameters]) { # EC key, make sure the curve is supported $curve = $pubKey.Parameters.Curve if ($curve -eq [Org.BouncyCastle.Asn1.Nist.NistNamedCurves]::GetByName('P-256').Curve) { $details.KeyLength = 'ec-256' } elseif ($curve -eq [Org.BouncyCastle.Asn1.Nist.NistNamedCurves]::GetByName('P-384').Curve) { $details.KeyLength = 'ec-384' } elseif ($curve -eq [Org.BouncyCastle.Asn1.Nist.NistNamedCurves]::GetByName('P-521').Curve) { $details.KeyLength = 'ec-521' } else { throw "Unsupported ECC curve. $($pubKey.Parameters.Curve.ToString())" } } else { throw "Unsupported key type." } Write-Debug "KeyLength = $($details.KeyLength)" # [Org.BouncyCastle.Asn1.Pkcs.CertificationRequestInfo] $csrInfo = $csr.GetCertificationRequestInfo() # grab the CN value $cn = ($csrInfo.Subject.GetValueList([Org.BouncyCastle.Asn1.X509.X509Name]::CN))[0] Write-Debug "CN = $cn" if ($cn) { $details.Domain = @($cn) } else { $details.Domain = @() } # grab the rest of the attributes [Org.BouncyCastle.Asn1.Asn1Set] # The Asn1Set is basically a nested collection of DerSequence objects $attr = $csrInfo.Attributes # Check if we have any attributes at all if ($attr.count -eq 0) { # throw if we have no CN if ($details.Domain.Count -eq 0) { throw "No Common Name (CN) or Subject Alternative Name (SAN) extensions found in certificate request." } Write-Warning "No Certficate Attributes found in CR." $details.OCSPMustStaple = $false return $details } # Find the sequence for "Certificate Extensions" (oid 1.2.840.113549.1.9.14) # [0] is the OID, [1] is the nested Asn1Set, # [1][0] should be the only DerSequence within the Ans1Set that contains additional nested DerSequence objects $extensions = ($attr | Where-Object { $_.Id -eq '1.2.840.113549.1.9.14'})[1][0] if (-not $extensions) { # throw if we have no names if ($details.Domain.Count -eq 0) { throw "No Common Name (CN) or Subject Alternative Name (SAN) extensions found in certificate request." } Write-Warning "No Certificate Extensions sequence found in CSR." $details.OCSPMustStaple = $false return $details } # Now find the sequence for "Subject Alternative Name" (oid 2.5.29.17) # [0] is the OID, [1] is the DerOctetString if ($sanSeq = $extensions | Where-Object { $_.Id -eq '2.5.29.17' }) { # convert to [Org.BouncyCastle.Asn1.X509.GeneralNames] $genNames = [Org.BouncyCastle.Asn1.X509.GeneralNames]::GetInstance([Org.BouncyCastle.Asn1.Asn1Object]::FromByteArray($sanSeq[1].GetOctets())) # and grab just the DNS names $SANs = ($genNames.GetNames() | Where-Object { $_.TagNo -eq 2 }).Name } if ($SANs) { Write-Debug "SANs = $(($SANs -join ','))" $details.Domain += $SANs | Where-Object { $_ -notin $details.Domain } } # throw if we have no names if ($details.Domain.Count -eq 0) { throw "No Common Name (CN) or Subject Alternative Name (SAN) extensions found in certificate request." } # Find the sequence for OCSP Must-Staple (oid 1.3.6.1.5.5.7.1.24) # and determine whether it's set if ($ocspSeq = $extensions | Where-Object { $_.Id -eq '1.3.6.1.5.5.7.1.24'}) { $details.OCSPMustStaple = ($ocspSeq[1].ToString() -eq '#3003020105') } else { $details.OCSPMustStaple = $false } Write-Debug "OCSP Must-Staple = $($details.OCSPMustStaple)" return $details } |