Attachment 932826 Details for Bug 1062444 – patch to use SHA-2 hashes

[patch] patch to use SHA-2 hashes

0001-keyutil-genkey-use-SHA-2-hashes-by-default-for-certs.patch (text/plain), 3.84 KB, created by Adam Williamson on 2014-08-29 23:15:21 UTC

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Creator: Adam Williamson

Created: 2014-08-29 23:15:21 UTC

Size: 3.84 KB

patch

obsolete

>From e810421866d7de22647470c347d2070b5cbfcd31 Mon Sep 17 00:00:00 2001
>From: Adam Williamson <awilliam@redhat.com>
>Date: Fri, 29 Aug 2014 14:58:39 -0700
>Subject: [PATCH] - keyutil, genkey: use SHA-2 hashes by default for certs
> (#1062444)
>
>Per http://csrc.nist.gov/publications/nistpubs/800-131A/sp800-131A.pdf
>SHA-1 should not be used for newly-generated certificates after 2013. This
>makes both certificate generation paths (NSS-native and OpenSSL-compatible)
>use SHA-256 by default.
>
>It also makes both paths use SHA-384 or SHA-512 for very long keys. It
>doesn't make sense to use a hash algorithm that provides less security
>than the public key, so when using a key longer than 3072 bits (which is
>considered to provide approximately 128 bits of security) we should move
>up from SHA-256 (which provides 128 bits of security), and when using a
>key longer than 7680 bits (which is considered to provide approximately
>192 bits of security) we should move up from SHA-384. NIST reference for
>the RSA key size strengths:
>http://csrc.nist.gov/publications/nistpubs/800-57/sp800-57_part1_rev3_general.pdf
>---
> crypto-utils.spec |  5 ++++-
> genkey.pl         | 10 ++++++++++
> keyutil.c         | 17 ++++++++++++++++-
> 3 files changed, 30 insertions(+), 2 deletions(-)
>
>diff --git a/crypto-utils.spec b/crypto-utils.spec
>index 1a8660e..b30935f 100644
>--- a/crypto-utils.spec
>+++ b/crypto-utils.spec
>@@ -4,7 +4,7 @@
> Summary: SSL certificate and key management utilities
> Name: crypto-utils
> Version: 2.4.1
>-Release: 55%{?dist}
>+Release: 56%{?dist}
> Group: Applications/System
> # certwatch.c is GPLv2
> # pemutil.c etc are (MPLv1.1+ or GPLv2+ or LPGLv2+)
>@@ -135,6 +135,9 @@ chmod -R u+w $RPM_BUILD_ROOT
> %{perl_vendorarch}/auto/Crypt
> 
> %changelog
>+* Fri Aug 29 2014 Adam Williamson <awilliam@redhat.com> - 2.4.1-55.1
>+- keyutil, genkey: use SHA-2 hashes by default for certs (#1062444)
>+
> * Wed Aug 27 2014 Jitka Plesnikova <jplesnik@redhat.com> - 2.4.1-55
> - Perl 5.20 rebuild
> 
>diff --git a/genkey.pl b/genkey.pl
>index 2f3b582..0f6b85a 100644
>--- a/genkey.pl
>+++ b/genkey.pl
>@@ -962,6 +962,15 @@ sub makeCertNSS
>     my $trustargs = $ca_mode ? "CT,," : "u,,";
>     $trustargs = "\"" . $trustargs. "\"";
>     
>+    # Hash algorithm choice: see http://www.keylength.com/en/4/ and
>+    # http://csrc.nist.gov/publications/nistpubs/800-131A/sp800-131A.pdf
>+    my $hashalg = "SHA256";
>+    if ($bits > 7680) {
>+        $hashalg = "SHA512";
>+    } elsif ($bits > 3072) {
>+        $hashalg = "SHA384";
>+    }
>+    
>     my $args = "-S ";
>     $args .= "-n $nickname ";
>     $args .= "-s $subject "; 
>@@ -976,6 +985,7 @@ sub makeCertNSS
>     $args .= "-d $modNssDbDir "; 
>     $args .= "-p $nssDBPrefix " if $nssDBPrefix;
>     $args .= "-o $certfile " if $certfile;
>+    $args .= "-Z $hashalg ";
>     
>     nssUtilCmd("$bindir/certutil", $args);
> 
>diff --git a/keyutil.c b/keyutil.c
>index eeb2019..80f33c3 100644
>--- a/keyutil.c
>+++ b/keyutil.c
>@@ -1522,7 +1522,22 @@ static int keyutil_main(
>     keyutil_extns[ext_policyConstr] = PR_FALSE;
>     keyutil_extns[ext_inhibitAnyPolicy] = PR_FALSE;
> 
>-    hashAlgTag = SEC_OID_SHA1;
>+    /* 
>+     * Hash algorithm should be at least SHA-256 after 2013:
>+     * http://csrc.nist.gov/publications/nistpubs/800-131A/sp800-131A.pdf
>+     * Per http://csrc.nist.gov/publications/nistpubs/800-57/sp800-57_part1_rev3_general.pdf
>+     * a 3072-bit key provides 128 bits of security and a 7680-bit key provides
>+     * 192 bits of security, so when producing certificates that use keys
>+     * longer than those lengths, we should use a correspondingly stronger
>+     * hash algorithm
>+     */
>+    if (keysize > 7680) {
>+        hashAlgTag = SEC_OID_SHA512;
>+    } else if (keysize > 3072) {
>+        hashAlgTag = SEC_OID_SHA384;
>+    } else {
>+        hashAlgTag = SEC_OID_SHA256;
>+    }
> 
>     /*  Make a cert request */
>     rv = CertReq(privkey, pubkey, rsaKey, hashAlgTag, subject,
>-- 
>2.1.0
>

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Attachments on bug 1062444: 932826 | 932828