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557fa38915
As noticed by @nobu https://github.com/rubygems/rubygems/pull/4989#discussion_r735674633
From wikipedia: https://en.wikipedia.org/wiki/SHA-1#SHA-1_pseudocode
> append ml, the original message length in bits, as a 64-bit big-endian integer.
`Q` is native endian, so little-endian on most modern hardware.
The original code from RubyDigest reverses the bytes:
d15f906caf/lib/ruby_digest.rb (L521)
But that makes the code non-portable, the correct way is to directly ask
for a big-endian representation.
https://github.com/rubygems/rubygems/commit/ba2be01ea4
71 lines
2.2 KiB
Ruby
71 lines
2.2 KiB
Ruby
# frozen_string_literal: true
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# This code was extracted from https://github.com/Solistra/ruby-digest which is under public domain
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module Bundler
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module Digest
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# The initial constant values for the 32-bit constant words A, B, C, D, and
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# E, respectively.
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SHA1_WORDS = [0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0].freeze
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# The 8-bit field used for bitwise `AND` masking. Defaults to `0xFFFFFFFF`.
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SHA1_MASK = 0xFFFFFFFF
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class << self
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def sha1(string)
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unless string.is_a?(String)
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raise TypeError, "can't convert #{string.class.inspect} into String"
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end
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buffer = string.b
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words = SHA1_WORDS.dup
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generate_split_buffer(buffer) do |chunk|
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w = []
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chunk.each_slice(4) do |a, b, c, d|
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w << (((a << 8 | b) << 8 | c) << 8 | d)
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end
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a, b, c, d, e = *words
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(16..79).each do |i|
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w[i] = SHA1_MASK & rotate((w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16]), 1)
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end
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0.upto(79) do |i|
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case i
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when 0..19
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f = ((b & c) | (~b & d))
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k = 0x5A827999
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when 20..39
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f = (b ^ c ^ d)
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k = 0x6ED9EBA1
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when 40..59
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f = ((b & c) | (b & d) | (c & d))
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k = 0x8F1BBCDC
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when 60..79
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f = (b ^ c ^ d)
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k = 0xCA62C1D6
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end
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t = SHA1_MASK & (SHA1_MASK & rotate(a, 5) + f + e + k + w[i])
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a, b, c, d, e = t, a, SHA1_MASK & rotate(b, 30), c, d # rubocop:disable Style/ParallelAssignment
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end
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mutated = [a, b, c, d, e]
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words.map!.with_index {|word, index| SHA1_MASK & (word + mutated[index]) }
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end
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words.pack("N*").unpack("H*").first
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end
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private
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def generate_split_buffer(string, &block)
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size = string.bytesize * 8
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buffer = string.bytes << 128
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buffer << 0 while buffer.size % 64 != 56
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buffer.concat([size].pack("Q>").bytes)
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buffer.each_slice(64, &block)
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end
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def rotate(value, spaces)
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value << spaces | value >> (32 - spaces)
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end
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end
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end
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end
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