[couchdb] 02/02: encryption password from config

[rn...@apache.org]

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rnewson pushed a commit to branch aegis_3.x
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit 45ab534c9f4f4227872dc7a53e0e6a9207465158
Author: Robert Newson <rn...@apache.org>
AuthorDate: Fri May 6 19:47:10 2022 +0100

    encryption password from config
---
 rel/overlay/etc/default.ini  |  2 ++
 src/couch/src/couch_file.erl | 27 +++++++++++++++++++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/rel/overlay/etc/default.ini b/rel/overlay/etc/default.ini
index 5fb45b5b5..98349f5eb 100644
--- a/rel/overlay/etc/default.ini
+++ b/rel/overlay/etc/default.ini
@@ -6,6 +6,8 @@ name = {{package_author_name}}
 uuid = {{uuid}}
 database_dir = {{data_dir}}
 view_index_dir = {{view_index_dir}}
+encryption_password = super_secret_password
+encryption_salt = no_saltier_than_this
 ; util_driver_dir =
 ; plugin_dir =
 ;os_process_timeout = 5000 ; 5 seconds. for view servers.
diff --git a/src/couch/src/couch_file.erl b/src/couch/src/couch_file.erl
index e4673c394..f52a12f9e 100644
--- a/src/couch/src/couch_file.erl
+++ b/src/couch/src/couch_file.erl
@@ -64,8 +64,6 @@
 %%  or {error, Reason} if the file could not be opened.
 %%----------------------------------------------------------------------
 
--define(AES_MASTER_KEY, <<0:256>>).
-
 open(Filepath) ->
     open(Filepath, []).
 
@@ -932,7 +930,7 @@ reset_eof(#file{} = File) ->
 %% we've wiped all the data, including the wrapped key, so we need a new one.
 init_key(#file{eof = 0} = File) ->
     Key = crypto:strong_rand_bytes(32),
-    WrappedKey = couch_keywrap:key_wrap(?AES_MASTER_KEY, Key),
+    WrappedKey = couch_keywrap:key_wrap(master_key(), Key),
     Header = <<?ENCRYPTED_HEADER, WrappedKey/binary>>,
     ok = file:write(File#file.fd, Header),
     ok = file:sync(File#file.fd),
@@ -942,7 +940,7 @@ init_key(#file{eof = 0} = File) ->
 init_key(#file{key = undefined} = File) ->
     case file:pread(File#file.fd, 0, 48) of
         {ok, <<?ENCRYPTED_HEADER, WrappedKey/binary>>} ->
-            case couch_keywrap:key_unwrap(?AES_MASTER_KEY, WrappedKey) of
+            case couch_keywrap:key_unwrap(master_key(), WrappedKey) of
                 fail ->
                     {error, unwrap_failed};
                 Key when is_binary(Key) ->
@@ -1023,6 +1021,27 @@ unpad(Pos, Bin) when is_binary(Bin) ->
     Result.
 
 
+master_key() ->
+    couch_pbkdf2:pbkdf2(sha256, master_password(), master_salt(), 100000).
+
+
+master_password() ->
+    case config:get("couchdb", "encryption_password") of
+        undefined ->
+            undefined;
+        Password ->
+            ?l2b(Password)
+    end.
+
+master_salt() ->
+    case config:get("couchdb", "encryption_salt") of
+        undefined ->
+            undefined;
+        Salt ->
+            ?l2b(Salt)
+    end.
+
+
 -ifdef(TEST).
 -include_lib("couch/include/couch_eunit.hrl").