[ruby-core:65988] [ruby-trunk - Feature #10098] [Assigned] [PATCH] Timing-safe string comparison for OpenSSL::HMAC

Issue #10098 has been updated by Tomoyuki Chikanaga.

Category changed from ext/openssl to core
Status changed from Open to Assigned
Assignee set to Yukihiro Matsumoto

The latest patch seems satisfy nobu, doesn't it?
At last we need to get approved from Matz.

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Feature #10098: [PATCH] Timing-safe string comparison for OpenSSL::HMAC
https://bugs.ruby-lang.org/issues/10098#change-49720

* Author: Matt U
* Status: Assigned
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* Category: core
* Target version: next minor
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I could be totally wrong, but it seems the standard library doesn't provide a reliable way of comparing hashes in constant-time.

* The docs for `OpenSSL::HMAC` encourage the use of `Digest#to_s` (see: http://ruby-doc.org/stdlib-2.1.0/libdoc/openssl/rdoc/OpenSSL/HMAC.html#method-c-new )
* Ruby's string comparison uses memcmp, which isn't timing safe (see: http://rxr.whitequark.org/mri/source/string.c#2382 )

With this patch I propose to add an additional method, `OpenSSL::HMAC#verify`, which takes a binary string with a digest and compares it against the computed hash.


---Files--------------------------------
hmac-timing.patch (2.5 KB)
hmac-timing.patch (2.48 KB)
tsafe_eql.patch (2.48 KB)
tsafe_inline.patch (3.51 KB)
0001-add-timing-safe-string-compare-method.patch (4.31 KB)


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