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  1. Oct 18, 2018
    • Viktor Dukhovni's avatar
      Only CA certificates can be self-issued · ed422a2d
      Viktor Dukhovni authored
      At the bottom of https://tools.ietf.org/html/rfc5280#page-12 and
      top of https://tools.ietf.org/html/rfc5280#page-13 (last paragraph
      of above https://tools.ietf.org/html/rfc5280#section-3.3), we see:
      
         This specification covers two classes of certificates: CA
         certificates and end entity certificates.  CA certificates may be
         further divided into three classes: cross-certificates, self-issued
         certificates, and self-signed certificates.  Cross-certificates are
         CA certificates in which the issuer and subject are different
         entities.  Cross-certificates describe a trust relationship between
         the two CAs.  Self-issued certificates are CA certificates in which
         the issuer and subject are the same entity.  Self-issued certificates
         are generated to support changes in policy or operations.  Self-
         signed certificates are self-issued certificates where the digital
         signature may be verified by the public key bound into the
         certificate.  Self-signed certificates are used to convey a public
         key for use to begin certification paths.  End entity certificates
         are issued to subjects that are not authorized to issue certificates.
      
      that the term "self-issued" is only applicable to CAs, not end-entity
      certificates.  In https://tools.ietf.org/html/rfc5280#section-4.2.1.9
      
      
      the description of path length constraints says:
      
         The pathLenConstraint field is meaningful only if the cA boolean is
         asserted and the key usage extension, if present, asserts the
         keyCertSign bit (Section 4.2.1.3).  In this case, it gives the
         maximum number of non-self-issued intermediate certificates that may
         follow this certificate in a valid certification path.  (Note: The
         last certificate in the certification path is not an intermediate
         certificate, and is not included in this limit.  Usually, the last
         certificate is an end entity certificate, but it can be a CA
         certificate.)
      
      This makes it clear that exclusion of self-issued certificates from
      the path length count applies only to some *intermediate* CA
      certificates.  A leaf certificate whether it has identical issuer
      and subject or whether it is a CA or not is never part of the
      intermediate certificate count.  The handling of all leaf certificates
      must be the same, in the case of our code to post-increment the
      path count by 1, so that we ultimately reach a non-self-issued
      intermediate it will be the first one (not zeroth) in the chain
      of intermediates.
      
      Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
      ed422a2d
  2. Oct 17, 2018
  3. Oct 16, 2018
    • Dr. Matthias St. Pierre's avatar
      DRBG: fix reseeding via RAND_add()/RAND_seed() with large input · 3064b551
      Dr. Matthias St. Pierre authored
      
      
      In pull request #4328 the seeding of the DRBG via RAND_add()/RAND_seed()
      was implemented by buffering the data in a random pool where it is
      picked up later by the rand_drbg_get_entropy() callback. This buffer
      was limited to the size of 4096 bytes.
      
      When a larger input was added via RAND_add() or RAND_seed() to the DRBG,
      the reseeding failed, but the error returned by the DRBG was ignored
      by the two calling functions, which both don't return an error code.
      As a consequence, the data provided by the application was effectively
      ignored.
      
      This commit fixes the problem by a more efficient implementation which
      does not copy the data in memory and by raising the buffer the size limit
      to INT32_MAX (2 gigabytes). This is less than the NIST limit of 2^35 bits
      but it was chosen intentionally to avoid platform dependent problems
      like integer sizes and/or signed/unsigned conversion.
      
      Additionally, the DRBG is now less permissive on errors: In addition to
      pushing a message to the openssl error stack, it enters the error state,
      which forces a reinstantiation on next call.
      
      Thanks go to Dr. Falko Strenzke for reporting this issue to the
      openssl-security mailing list. After internal discussion the issue
      has been categorized as not being security relevant, because the DRBG
      reseeds automatically and is fully functional even without additional
      randomness provided by the application.
      
      Fixes #7381
      
      Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
      (Merged from https://github.com/openssl/openssl/pull/7382)
      3064b551
  4. Oct 13, 2018
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