From: knu@...
Date: 2014-07-15T14:28:44+00:00
Subject: [ruby-core:63736] [ruby-trunk - Bug #9659] crash in FIPS mode after unchecked algo->init_func failure

Issue #9659 has been updated by Akinori MUSHA.


The above set of patches looks good to me.

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Bug #9659: crash in FIPS mode after unchecked algo->init_func failure
https://bugs.ruby-lang.org/issues/9659#change-47780

* Author: Jared Jennings
* Status: Feedback
* Priority: Normal
* Assignee: 
* Category: ext
* Target version: current: 2.2.0
* ruby -v: ruby 1.8.7 (2011-06-30 patchlevel 352) [x86_64-linux]
* Backport: 2.0.0: REQUIRED, 2.1: REQUIRED
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This is just like #4944, but in the `digest` extension instead of the `openssl` extension.

On my host, which is configured for FIPS 140-2 compliance (this is a U.S. Government security standard), OpenSSL refuses to perform an MD5 checksum. It indicates this refusal when the digest algorithm initialization function is called: this function returns a 0 indicating failure instead of a 1 indicating success. But it's just a bunch of arithmetic; how can it fail? So the return code is ignored. But if the initialization fails, and we go on trying to use the algorithm, the Ruby interpreter crashes:

~~~
  $ OPENSSL_FORCE_FIPS_MODE= ruby -rdigest -e "puts Digest::MD5.hexdigest('hi')"
  md5_dgst.c(78): OpenSSL internal error, assertion failed: Digest MD5 forbidden in FIPS mode!
  Aborted (core dumped)
~~~

The digest extension, in the `rb_digest_base_alloc`, `rb_digest_base_reset`, and `rb_digest_base_finish` functions, is ignoring the return code of `algo->init_func`. If OpenSSL is present at build time, `algo->init_func` works out to be the `MD5_Init` function from OpenSSL. This function, according to its man page, returns a 1 for success or 0 for failure.

I see the problem under Ruby 1.8.7 as patched by Red Hat; I can't easily build the trunk on my system, but it looks like in r43668 the return value still isn't being checked in these three places:

 * source:ext/digest/digest.c@43668#L551
 * source:ext/digest/digest.c@43668#L589
 * source:ext/digest/digest.c@43668#L627

---Files--------------------------------
002-builtin-indicate-digest-failure.patch (10.4 KB)
001-detect-digest-failure.patch (2.12 KB)
003-digest-openssl-md5-use-evp-api.patch (1.8 KB)


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