From d736643099570f6a945ee46956f849e545ccc187 Mon Sep 17 00:00:00 2001
From: Christian Poessinger <christian@poessinger.com>
Date: Sun, 12 Jul 2020 14:50:17 +0200
Subject: snmp: T2687: replace 3rd party hash library with custom code

The 3rd party library used for calculating the SNMP hashes in advance only
worked for SHA and nod for MD5 as SHA was hardcoded [1]. The code has been
replaced by a class-less implementation providing only the required
functionality.

[1]: https://github.com/TheMysteriousX/SNMPv3-Hash-Generator/issues/2
---
 src/conf_mode/snmp.py | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

(limited to 'src/conf_mode/snmp.py')

diff --git a/src/conf_mode/snmp.py b/src/conf_mode/snmp.py
index f3c91d987..e9806ef47 100755
--- a/src/conf_mode/snmp.py
+++ b/src/conf_mode/snmp.py
@@ -20,7 +20,7 @@ from sys import exit
 
 from vyos.config import Config
 from vyos.configverify import verify_vrf
-from vyos.snmpv3_hashgen import Hashgen
+from vyos.snmpv3_hashgen import plaintext_to_md5, plaintext_to_sha1, random
 from vyos.template import render
 from vyos.util import call
 from vyos.validate import is_ipv4, is_addr_assigned
@@ -86,9 +86,8 @@ def get_config():
     snmp['version'] = version_data['version']
 
     # create an internal snmpv3 user of the form 'vyosxxxxxxxxxxxxxxxx'
-    # os.urandom(8) returns 8 bytes of random data
-    snmp['vyos_user'] = 'vyos' + Hashgen.random_string(len=8)
-    snmp['vyos_user_pass'] = Hashgen.random_string(len=16)
+    snmp['vyos_user'] = 'vyos' + random(8)
+    snmp['vyos_user_pass'] = random(16)
 
     if conf.exists('community'):
         for name in conf.list_nodes('community'):
@@ -524,19 +523,20 @@ def generate(snmp):
         os.environ["vyos_libexec_dir"] = "/usr/libexec/vyos"
 
         for user in snmp['v3_users']:
-            hash = Hashgen.sha1 if user['authProtocol'] in 'sha1' else Hashgen.md5
+            if user['authProtocol'] == 'sha':
+                hash = plaintext_to_sha1
+            else:
+                hash = plaintext_to_md5
 
             if user['authPassword']:
-                Kul_auth = Hashgen.derive_msg(user['authPassword'], snmp['v3_engineid'])
-                user['authMasterKey'] = hash(Kul_auth)
+                user['authMasterKey'] = hash(user['authPassword'], snmp['v3_engineid'])
                 user['authPassword'] = ''
 
                 call('/opt/vyatta/sbin/my_set service snmp v3 user "{name}" auth encrypted-password "{authMasterKey}" > /dev/null'.format(**user))
                 call('/opt/vyatta/sbin/my_delete service snmp v3 user "{name}" auth plaintext-password > /dev/null'.format(**user))
 
             if user['privPassword']:
-                Kul_priv = Hashgen.derive_msg(user['privPassword'], snmp['v3_engineid'])
-                user['privMasterKey'] = hash(Kul_priv)
+                user['privMasterKey'] = hash(user['privPassword'], snmp['v3_engineid'])
                 user['privPassword'] = ''
 
                 call('/opt/vyatta/sbin/my_set service snmp v3 user "{name}" privacy encrypted-password "{privMasterKey}" > /dev/null'.format(**user))
-- 
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