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authorBen Toews <mastahyeti@users.noreply.github.com>2016-01-04 12:23:55 -0700
committerBen Toews <mastahyeti@users.noreply.github.com>2016-01-04 12:26:38 -0700
commit3e98819e20bc113343d4d4c0df614865ad5a9d3a (patch)
treefa003a9cbbec97f7d1cdb9a87a2c065473ad2e4d /actionpack/lib/action_controller/metal/request_forgery_protection.rb
parente165f7fa6044926796c9d9a8bb9a81bc78431d4f (diff)
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add option for per-form CSRF tokens
Diffstat (limited to 'actionpack/lib/action_controller/metal/request_forgery_protection.rb')
-rw-r--r--actionpack/lib/action_controller/metal/request_forgery_protection.rb65
1 files changed, 54 insertions, 11 deletions
diff --git a/actionpack/lib/action_controller/metal/request_forgery_protection.rb b/actionpack/lib/action_controller/metal/request_forgery_protection.rb
index 26c4550f89..91b3403ad5 100644
--- a/actionpack/lib/action_controller/metal/request_forgery_protection.rb
+++ b/actionpack/lib/action_controller/metal/request_forgery_protection.rb
@@ -81,6 +81,10 @@ module ActionController #:nodoc:
config_accessor :forgery_protection_origin_check
self.forgery_protection_origin_check = false
+ # Controls whether form-action/method specific CSRF tokens are used.
+ config_accessor :per_form_csrf_tokens
+ self.per_form_csrf_tokens = false
+
helper_method :form_authenticity_token
helper_method :protect_against_forgery?
end
@@ -277,16 +281,25 @@ module ActionController #:nodoc:
end
# Sets the token value for the current session.
- def form_authenticity_token
- masked_authenticity_token(session)
+ def form_authenticity_token(form_options: {})
+ masked_authenticity_token(session, form_options: form_options)
end
# Creates a masked version of the authenticity token that varies
# on each request. The masking is used to mitigate SSL attacks
# like BREACH.
- def masked_authenticity_token(session)
+ def masked_authenticity_token(session, form_options: {})
+ action, method = form_options.values_at(:action, :method)
+
+ raw_token = if per_form_csrf_tokens && action && method
+ action_path = normalize_action_path(action)
+ per_form_csrf_token(session, action_path, method)
+ else
+ real_csrf_token(session)
+ end
+
one_time_pad = SecureRandom.random_bytes(AUTHENTICITY_TOKEN_LENGTH)
- encrypted_csrf_token = xor_byte_strings(one_time_pad, real_csrf_token(session))
+ encrypted_csrf_token = xor_byte_strings(one_time_pad, raw_token)
masked_token = one_time_pad + encrypted_csrf_token
Base64.strict_encode64(masked_token)
end
@@ -316,28 +329,54 @@ module ActionController #:nodoc:
compare_with_real_token masked_token, session
elsif masked_token.length == AUTHENTICITY_TOKEN_LENGTH * 2
- # Split the token into the one-time pad and the encrypted
- # value and decrypt it
- one_time_pad = masked_token[0...AUTHENTICITY_TOKEN_LENGTH]
- encrypted_csrf_token = masked_token[AUTHENTICITY_TOKEN_LENGTH..-1]
- csrf_token = xor_byte_strings(one_time_pad, encrypted_csrf_token)
-
- compare_with_real_token csrf_token, session
+ csrf_token = unmask_token(masked_token)
+ compare_with_real_token(csrf_token, session) ||
+ valid_per_form_csrf_token?(csrf_token, session)
else
false # Token is malformed
end
end
+ def unmask_token(masked_token)
+ # Split the token into the one-time pad and the encrypted
+ # value and decrypt it
+ one_time_pad = masked_token[0...AUTHENTICITY_TOKEN_LENGTH]
+ encrypted_csrf_token = masked_token[AUTHENTICITY_TOKEN_LENGTH..-1]
+ xor_byte_strings(one_time_pad, encrypted_csrf_token)
+ end
+
def compare_with_real_token(token, session)
ActiveSupport::SecurityUtils.secure_compare(token, real_csrf_token(session))
end
+ def valid_per_form_csrf_token?(token, session)
+ if per_form_csrf_tokens
+ correct_token = per_form_csrf_token(
+ session,
+ normalize_action_path(request.fullpath),
+ request.request_method
+ )
+
+ ActiveSupport::SecurityUtils.secure_compare(token, correct_token)
+ else
+ false
+ end
+ end
+
def real_csrf_token(session)
session[:_csrf_token] ||= SecureRandom.base64(AUTHENTICITY_TOKEN_LENGTH)
Base64.strict_decode64(session[:_csrf_token])
end
+ def per_form_csrf_token(session, action_path, method)
+ OpenSSL::HMAC.digest(
+ OpenSSL::Digest::SHA256.new,
+ real_csrf_token(session),
+ [action_path, method.downcase].join("#")
+ )
+ end
+
def xor_byte_strings(s1, s2)
s1.bytes.zip(s2.bytes).map { |(c1,c2)| c1 ^ c2 }.pack('c*')
end
@@ -362,5 +401,9 @@ module ActionController #:nodoc:
true
end
end
+
+ def normalize_action_path(action_path)
+ action_path.split('?').first.to_s.chomp('/')
+ end
end
end