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-rw-r--r--lib/cgi/session.rb4
-rw-r--r--lib/securerandom.rb128
2 files changed, 130 insertions, 2 deletions
diff --git a/lib/cgi/session.rb b/lib/cgi/session.rb
index 7539be37c3..8a6ba24c2c 100644
--- a/lib/cgi/session.rb
+++ b/lib/cgi/session.rb
@@ -174,9 +174,9 @@ class CGI
# is used internally for automatically generated
# session ids.
def create_new_id
- require 'secrand'
+ require 'securerandom'
begin
- session_id = SecRand.hex(16)
+ session_id = SecureRandom.hex(16)
rescue NotImplementedError
require 'digest/md5'
md5 = Digest::MD5::new
diff --git a/lib/securerandom.rb b/lib/securerandom.rb
new file mode 100644
index 0000000000..e448559736
--- /dev/null
+++ b/lib/securerandom.rb
@@ -0,0 +1,128 @@
+# = Secure random number generator interface.
+#
+# This library is a interface for secure random number generator which is
+# suitable for HTTP cookies, nonces, etc.
+#
+# It supports following secure random number generators.
+#
+# * openssl
+# * /dev/urandom
+#
+# == Example
+#
+# # random hexadecimal string.
+# p SecureRandom.hex(10) #=> "52750b30ffbc7de3b362"
+# p SecureRandom.hex(10) #=> "92b15d6c8dc4beb5f559"
+# p SecureRandom.hex(11) #=> "6aca1b5c58e4863e6b81b8"
+# p SecureRandom.hex(12) #=> "94b2fff3e7fd9b9c391a2306"
+# p SecureRandom.hex(13) #=> "39b290146bea6ce975c37cfc23"
+# ...
+#
+# # random base64 string.
+# p SecureRandom.base64(10) #=> "EcmTPZwWRAozdA=="
+# p SecureRandom.base64(10) #=> "9b0nsevdwNuM/w=="
+# p SecureRandom.base64(10) #=> "KO1nIU+p9DKxGg=="
+# p SecureRandom.base64(11) #=> "l7XEiFja+8EKEtY="
+# p SecureRandom.base64(12) #=> "7kJSM/MzBJI+75j8"
+# p SecureRandom.base64(13) #=> "vKLJ0tXBHqQOuIcSIg=="
+# ...
+#
+# # random binary string.
+# p SecureRandom.random_bytes(10) #=> "\016\t{\370g\310pbr\301"
+# p SecureRandom.random_bytes(10) #=> "\323U\030TO\234\357\020\a\337"
+# ...
+
+begin
+ require 'openssl'
+rescue LoadError
+end
+
+module SecureRandom
+ # SecureRandom.random_bytes generates a random binary string.
+ #
+ # The argument n specifies the length of the result string.
+ #
+ # If secure random number generator is not available,
+ # NotImplementedError is raised.
+ def self.random_bytes(n=nil)
+ n ||= 16
+ if defined? OpenSSL::Random
+ return OpenSSL::Random.random_bytes(n)
+ end
+ if !defined?(@has_urandom) || @has_urandom
+ @has_urandom = false
+ flags = File::RDONLY
+ flags |= File::NONBLOCK if defined? File::NONBLOCK
+ flags |= File::NOCTTY if defined? File::NOCTTY
+ flags |= File::NOFOLLOW if defined? File::NOFOLLOW
+ begin
+ File.open("/dev/urandom", flags) {|f|
+ unless f.stat.chardev?
+ raise Errno::ENOENT
+ end
+ @has_urandom = true
+ ret = f.readpartial(n)
+ if ret.length != n
+ raise NotImplementedError, "Unexpected partial read from random device"
+ end
+ return ret
+ }
+ rescue Errno::ENOENT
+ raise NotImplementedError, "No random device"
+ end
+ end
+ raise NotImplementedError, "No random device"
+ end
+
+ # SecureRandom.hex generates a random hex string.
+ #
+ # The argument n specifies the length of the random length.
+ # The length of the result string is twice of n.
+ #
+ # If secure random number generator is not available,
+ # NotImplementedError is raised.
+ def self.hex(n=nil)
+ random_bytes(n).unpack("H*")[0]
+ end
+
+ # SecureRandom.base64 generates a random base64 string.
+ #
+ # The argument n specifies the length of the random length.
+ # The length of the result string is about 4/3 of n.
+ #
+ # If secure random number generator is not available,
+ # NotImplementedError is raised.
+ def self.base64(n=nil)
+ [random_bytes(n)].pack("m*").delete("\n")
+ end
+
+ # SecureRandom.random_number generates a random number.
+ #
+ # If an positive integer is given as n,
+ # SecureRandom.random_number returns an integer:
+ # 0 <= SecureRandom.random_number(n) < n.
+ #
+ # If 0 is given or an argument is not given,
+ # SecureRandom.random_number returns an float:
+ # 0.0 <= SecureRandom.random_number() < 1.0.
+ def self.random_number(n=0)
+ if 0 < n
+ hex = n.to_s(16)
+ hex = '0' + hex if (hex.length & 1) == 1
+ bin = [hex].pack("H*")
+ mask = bin[0].ord
+ mask |= mask >> 1
+ mask |= mask >> 2
+ mask |= mask >> 4
+ begin
+ rnd = SecureRandom.random_bytes(bin.length)
+ rnd[0] = (rnd[0].ord & mask).chr
+ end until rnd < bin
+ rnd.unpack("H*")[0].hex
+ else
+ # assumption: Float::MANT_DIG <= 64
+ i64 = SecureRandom.random_bytes(8).unpack("Q")[0]
+ Math.ldexp(i64 >> (64-Float::MANT_DIG), -Float::MANT_DIG)
+ end
+ end
+end