[Security] Made optimization on constant-time algorithm removing modulus operator #11574
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Why is it labelled as |
| // Extend strings to avoid uninitialized string offsets | ||
| $tmp = $knownString; | ||
| $knownString .= $userInput; | ||
| $userInput .= $tmp; |
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this line is not needed, given we iterate over the user input length, so we will never go further (there is no modulus operator applied when accessing the userInput char in the current implementation either)
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Thank you @yosmanyga. |
fabpot
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Aug 31, 2014
…removing modulus operator (yosmanyga) This PR was merged into the 2.3 branch. Discussion ---------- [Security] Made optimization on constant-time algorithm removing modulus operator | Q | A | ------------- | --- | Bug fix? | no | New feature? | no | BC breaks? | no | Deprecations? | no | Tests pass? | yes | Fixed tickets | - | License | MIT | Doc PR | - This fix improves the constant-time algorithm used to compare strings, as it removes the `%` operator inside the loop. Commits ------- 000bd0d Made optimization deprecating modulus operator
| $knownLen = strlen($knownString); | ||
| $userLen = strlen($userInput); | ||
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| // Extend know string to avoid uninitialized string offsets |
This was referenced Sep 3, 2014
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This fix improves the constant-time algorithm used to compare strings, as it removes the
%operator inside the loop.