crypto: Update the REQUIREMENTS

Update after call with the GnuTLS maintainer to see what is supported in
GnuTLS, what is working in FIPS mode or not, and what features we require
to move to GnuTLS in future. The benefit will be FIPS certification and
more hardware accelerated crypto.

Bugs have been opened against GnuTLS to implment the missing features or
add functions to declare use of old crypto functions as non-crypto use.

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>

1 files changed, 47 insertions, 23 deletions

diff --git a/lib/crypto/REQUIREMENTS b/lib/crypto/REQUIREMENTS
index 351c2bb99b4..5e02aea4071 100644
--- a/lib/crypto/REQUIREMENTS
+++ b/lib/crypto/REQUIREMENTS
@@ -4,14 +4,21 @@ This list is to allow research into using external crypto libraries.
 Those possibly supported in the git version of GnuTLS are indicated as '# GNUTLS'
 Those possibly supported in the git version of nettle are indicated as '# NETTLE'
 
+For Samba AD with Heimdal gnutls >= 3.0.0 is required
+For Samba AD with MIT kerberos gnutls >= 3.4.7 is required
+Samba FS with MS Catalog support will require gnutls >= 3.5.6
+
+GnuTLS Milestone for Samba support:
+ - https://gitlab.com/gnutls/gnutls/milestones/14
+
 ARCFOUR (RC4)
  - the old SamOEMHash
  - Password encryption on SAMR for password set/get
  - NETLOGON SamLogon session keys
  - Schannel
- - genrate_random_data()
+ - generate_random_data()
 
- # GNUTLS
+ # GNUTLS >= 3.0.0
  # NETTLE
 
 DES
@@ -21,49 +28,60 @@ DES
  - ServerGetTrustInfo returned passwords
  - RID encryption of passwords
 
- # NETTLE
+ # No support in gnutls, it cannot be a certified use of crypto
+ # NETTLE (any version)
 
 3DES
- - NETLOGON Credentials
+ - NETLOGON Credentials (can't find any use in Samba)
 
+3DES-CBC
+ - backupkey (uses heimdal lib or gnutls with mit krb5)
+
+ # gnutls >= 3.4.7 (3des cbc with 192 bit key is supported); can no longer be a certified use of crypto
  # NETTLE
 
 CRC32
  - DRSUAPI replication replicated secrets
 
-AES CFB8
+This is no crypto
+
+AES 128 in 8-bit CFB mode
  - SCHANNEL
  - NETLOGON SamLogon session keys
 
- # NETTLE (AES-NI available)
+ # Missing in GNUTLS -> Bug opened
+ # NETTLE 3.4 contains CFB - possibly 128-bit mode (AES-NI available)
 
 AES128 CCM
  - SMB2 2.24 SMB encryption
 
- # GNUTLS
+ # GNUTLS >= 3.4.0
  # NETTLE (AES-NI available)
 
 AES128 GCM
  - SMB2 3.10 SMB encryption
 
- # GNUTLS
+ # GNUTLS >= 3.0.0
  # NETTLE (AES-NI available)
 
 AES128 CMAC
  - SMB2 0x224 SMB Signing
 
+ # Missing in GNUTLS - > Bug opened
+ # Missing in NETTLE -> Bug opened
+
 MD4
  - NTLM password hash
- - genrate_random_number()
 
+ # Cannot be certified; considered non-crypto
  # NETTLE
 
 MD5
- - NTLM2
- - SCHANNEL
- - NTLMSSP
- - NETLOGON computer credentials
- - DRSUAPI blob encryption
+ - NTLM2 (can be considered non-crypto use of MD5)
+ - SCHANNEL (it's ok to fail in FIPS140 mode, as there are alternatives)
+ - NTLMSSP (it's ok to fail in FIPS140 mode, replaced by kerberos)
+ - NETLOGON computer credentials (it's ok to fail in FIPS140 mode, as there are alternatives)
+ - DRSUAPI blob encryption (can be considered non-crypto use as it is over DC-RPC which is encrypted)
  - SAMR/wkssvc password change/set encryption
  - vfs_fruit
  - vfs_streams_xattr
@@ -72,44 +90,50 @@ MD5
  - SMB1 SMB signing
  - NTP ntp_signd
 
- # GNUTLS
+maybe use gnutls_fips140_mode_enabled() and enable only SMB2/3 when in fips mode?
+
+ # GNUTLS >= 3.0.0 (Will fail in FIPS mode, for non-crypto -> https://gitlab.com/gnutls/gnutls/merge_requests/572 , open bug for RC4, MD5 being available for non-crypto use )
  # NETTLE
 
 HMAC-MD5
  - NTLMv2
 
- # GNUTLS
+ # GNUTLS >= 3.0.0 (non-crypto)
  # NETTLE
 
-HMACSHA256
+HMAC-SHA256
  - SMB2 < 2.24 SMB signing
  - SMB2 Key derivation
 
- # GNUTLS
+ # GNUTLS (>= 3.0.0)
  # NETTLE
 
-HMACSHA1
+HMAC-SHA1
  - BackupKey ServerWrap
 
- # GNUTLS
+ # GNUTLS (>= 3.0.0)
  # NETTLE
 
 SHA256
  - Security Descriptor hash for vfs_acl_xattr
  - oLschema2ldif
 
- # GNUTLS
+ # GNUTLS (>= 3.0.0)
  # NETTLE
 
 SHA512
  - SMB2 Pre-auth integrity verification
  - BackupKey ClientWrap
 
- # GNUTLS
+ # GNUTLS (>= 3.0.0)
  # NETTLE
 
 RSA
  - BackupKey ClientWrap
 
- # GNUTLS
+ # GNUTLS (>= 3.0.0)
  # NETTLE
+
+
+GNUTLS
+Use gnutls_rnd() in generate_random_buffer() to increase speed