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require 'openssl'
require 'net/ssh/authentication/pub_key_fingerprint'
module OpenSSL
# This class is originally defined in the OpenSSL module. As needed, methods
# have been added to it by the Net::SSH module for convenience in dealing with
# SSH functionality.
class BN
# Converts a BN object to a string. The format used is that which is
# required by the SSH2 protocol.
def to_ssh
if zero?
return [0].pack("N")
else
buf = to_s(2)
if buf.getbyte(0)[7] == 1
return [buf.length + 1, 0, buf].pack("NCA*")
else
return [buf.length, buf].pack("NA*")
end
end
end
end
module PKey
class PKey
include Net::SSH::Authentication::PubKeyFingerprint
end
# This class is originally defined in the OpenSSL module. As needed, methods
# have been added to it by the Net::SSH module for convenience in dealing
# with SSH functionality.
class DH
# Determines whether the pub_key for this key is valid. (This algorithm
# lifted more-or-less directly from OpenSSH, dh.c, dh_pub_is_valid.)
def valid?
return false if pub_key.nil? || pub_key < 0
bits_set = 0
pub_key.num_bits.times { |i| bits_set += 1 if pub_key.bit_set?(i) }
return (bits_set > 1 && pub_key < p)
end
end
# This class is originally defined in the OpenSSL module. As needed, methods
# have been added to it by the Net::SSH module for convenience in dealing
# with SSH functionality.
class RSA
# Returns "ssh-rsa", which is the description of this key type used by the
# SSH2 protocol.
def ssh_type
"ssh-rsa"
end
alias ssh_signature_type ssh_type
# Converts the key to a blob, according to the SSH2 protocol.
def to_blob
@blob ||= Net::SSH::Buffer.from(:string, ssh_type, :bignum, e, :bignum, n).to_s
end
# Verifies the given signature matches the given data.
def ssh_do_verify(sig, data, options = {})
digester =
if options[:host_key] == "rsa-sha2-512"
OpenSSL::Digest::SHA512.new
elsif options[:host_key] == "rsa-sha2-256"
OpenSSL::Digest::SHA256.new
else
OpenSSL::Digest::SHA1.new
end
verify(digester, sig, data)
end
# Returns the signature for the given data.
def ssh_do_sign(data)
sign(OpenSSL::Digest::SHA1.new, data)
end
end
# This class is originally defined in the OpenSSL module. As needed, methods
# have been added to it by the Net::SSH module for convenience in dealing
# with SSH functionality.
class DSA
# Returns "ssh-dss", which is the description of this key type used by the
# SSH2 protocol.
def ssh_type
"ssh-dss"
end
alias ssh_signature_type ssh_type
# Converts the key to a blob, according to the SSH2 protocol.
def to_blob
@blob ||= Net::SSH::Buffer.from(:string, ssh_type,
:bignum, p, :bignum, q, :bignum, g, :bignum, pub_key).to_s
end
# Verifies the given signature matches the given data.
def ssh_do_verify(sig, data, options = {})
sig_r = sig[0, 20].unpack("H*")[0].to_i(16)
sig_s = sig[20, 20].unpack("H*")[0].to_i(16)
a1sig = OpenSSL::ASN1::Sequence([
OpenSSL::ASN1::Integer(sig_r),
OpenSSL::ASN1::Integer(sig_s)
])
return verify(OpenSSL::Digest::SHA1.new, a1sig.to_der, data)
end
# Signs the given data.
def ssh_do_sign(data)
sig = sign(OpenSSL::Digest::SHA1.new, data)
a1sig = OpenSSL::ASN1.decode(sig)
sig_r = a1sig.value[0].value.to_s(2)
sig_s = a1sig.value[1].value.to_s(2)
raise OpenSSL::PKey::DSAError, "bad sig size" if sig_r.length > 20 || sig_s.length > 20
sig_r = "\0" * (20 - sig_r.length) + sig_r if sig_r.length < 20
sig_s = "\0" * (20 - sig_s.length) + sig_s if sig_s.length < 20
return sig_r + sig_s
end
end
# This class is originally defined in the OpenSSL module. As needed, methods
# have been added to it by the Net::SSH module for convenience in dealing
# with SSH functionality.
class EC
CurveNameAlias = {
'nistp256' => 'prime256v1',
'nistp384' => 'secp384r1',
'nistp521' => 'secp521r1'
}.freeze
CurveNameAliasInv = {
'prime256v1' => 'nistp256',
'secp384r1' => 'nistp384',
'secp521r1' => 'nistp521'
}.freeze
def self.read_keyblob(curve_name_in_type, buffer)
curve_name_in_key = buffer.read_string
unless curve_name_in_type == curve_name_in_key
raise Net::SSH::Exception, "curve name mismatched (`#{curve_name_in_key}' with `#{curve_name_in_type}')"
end
public_key_oct = buffer.read_string
begin
key = OpenSSL::PKey::EC.new(OpenSSL::PKey::EC::CurveNameAlias[curve_name_in_key])
group = key.group
point = OpenSSL::PKey::EC::Point.new(group, OpenSSL::BN.new(public_key_oct, 2))
key.public_key = point
return key
rescue OpenSSL::PKey::ECError
raise NotImplementedError, "unsupported key type `#{type}'"
end
end
# Returns the description of this key type used by the
# SSH2 protocol, like "ecdsa-sha2-nistp256"
def ssh_type
"ecdsa-sha2-#{CurveNameAliasInv[group.curve_name]}"
end
alias ssh_signature_type ssh_type
def digester
if group.curve_name =~ /^[a-z]+(\d+)\w*\z/
curve_size = Regexp.last_match(1).to_i
if curve_size <= 256
OpenSSL::Digest::SHA256.new
elsif curve_size <= 384
OpenSSL::Digest::SHA384.new
else
OpenSSL::Digest::SHA512.new
end
else
OpenSSL::Digest::SHA256.new
end
end
private :digester
# Converts the key to a blob, according to the SSH2 protocol.
def to_blob
@blob ||= Net::SSH::Buffer.from(:string, ssh_type,
:string, CurveNameAliasInv[group.curve_name],
:mstring, public_key.to_bn.to_s(2)).to_s
@blob
end
# Verifies the given signature matches the given data.
def ssh_do_verify(sig, data, options = {})
digest = digester.digest(data)
a1sig = nil
begin
sig_r_len = sig[0, 4].unpack('H*')[0].to_i(16)
sig_l_len = sig[4 + sig_r_len, 4].unpack('H*')[0].to_i(16)
sig_r = sig[4, sig_r_len].unpack('H*')[0]
sig_s = sig[4 + sig_r_len + 4, sig_l_len].unpack('H*')[0]
a1sig = OpenSSL::ASN1::Sequence([
OpenSSL::ASN1::Integer(sig_r.to_i(16)),
OpenSSL::ASN1::Integer(sig_s.to_i(16))
])
rescue StandardError
end
if a1sig.nil?
return false
else
dsa_verify_asn1(digest, a1sig.to_der)
end
end
# Returns the signature for the given data.
def ssh_do_sign(data)
digest = digester.digest(data)
sig = dsa_sign_asn1(digest)
a1sig = OpenSSL::ASN1.decode(sig)
sig_r = a1sig.value[0].value
sig_s = a1sig.value[1].value
Net::SSH::Buffer.from(:bignum, sig_r, :bignum, sig_s).to_s
end
class Point
# Returns the description of this key type used by the
# SSH2 protocol, like "ecdsa-sha2-nistp256"
def ssh_type
"ecdsa-sha2-#{CurveNameAliasInv[group.curve_name]}"
end
alias ssh_signature_type ssh_type
# Converts the key to a blob, according to the SSH2 protocol.
def to_blob
@blob ||= Net::SSH::Buffer.from(:string, ssh_type,
:string, CurveNameAliasInv[group.curve_name],
:mstring, to_bn.to_s(2)).to_s
@blob
end
end
end
end
end
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