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Posted to commits@couchdb.apache.org by rn...@apache.org on 2022/05/10 13:34:02 UTC
[couchdb] 01/01: Add key rotation facility
This is an automated email from the ASF dual-hosted git repository.
rnewson pushed a commit to branch aegis_3.x
in repository https://gitbox.apache.org/repos/asf/couchdb.git
commit 4973c0494e8d83fea5ab8bca8b3e23e0daa6c6fb
Author: Robert Newson <rn...@apache.org>
AuthorDate: Tue May 10 08:29:45 2022 +0100
Add key rotation facility
---
rel/overlay/etc/default.ini | 9 +++-
src/couch/src/couch_file.erl | 107 ++++++++++++++++++++++++++-----------------
2 files changed, 72 insertions(+), 44 deletions(-)
diff --git a/rel/overlay/etc/default.ini b/rel/overlay/etc/default.ini
index 98349f5eb..bfda46f44 100644
--- a/rel/overlay/etc/default.ini
+++ b/rel/overlay/etc/default.ini
@@ -6,8 +6,6 @@ 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.
@@ -749,3 +747,10 @@ port = {{prometheus_port}}
; to disable this setting could be if the views need an upgrade but located on
; read-only file system.
;commit_on_header_upgrade = true
+
+[encryption]
+wrapping_key_id = bec46c7438e685d6
+
+[encryption_keys]
+254abda45788029b = 0585d781ef090ee26f329a36f66935ce
+bec46c7438e685d6 = e6f598615eb7502b473b101d64f56410
\ No newline at end of file
diff --git a/src/couch/src/couch_file.erl b/src/couch/src/couch_file.erl
index 6198d8f9a..d63ebde7b 100644
--- a/src/couch/src/couch_file.erl
+++ b/src/couch/src/couch_file.erl
@@ -23,7 +23,6 @@
-define(IS_OLD_STATE(S), is_pid(S#file.db_monitor)).
-define(PREFIX_SIZE, 5).
-define(DEFAULT_READ_COUNT, 1024).
--define(ENCRYPTED_HEADER, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15).
-type block_id() :: non_neg_integer().
-type location() :: non_neg_integer().
@@ -39,6 +38,12 @@
dec
}).
+-record(encryption_header, {
+ version = 1,
+ wrapping_key_id,
+ wrapped_key
+}).
+
% public API
-export([open/1, open/2, close/1, bytes/1, sync/1, truncate/2, set_db_pid/2]).
-export([pread_term/2, pread_iolist/2, pread_binary/2]).
@@ -619,18 +624,10 @@ handle_call({append_bins, Bins}, _From, #file{eof = Pos} = File) ->
Error ->
{reply, Error, reset_eof(File)}
end;
-handle_call({write_header, Bin}, _From, #file{eof = Pos} = File) ->
- BinSize = byte_size(Bin),
- case Pos rem ?SIZE_BLOCK of
- 0 ->
- Padding = <<>>;
- BlockOffset ->
- Padding = <<0:(8 * (?SIZE_BLOCK - BlockOffset))>>
- end,
- FinalBin = [Padding, <<1, BinSize:32/integer>> | make_blocks(5, [Bin])],
- case encrypted_write(File, FinalBin) of
- ok ->
- {reply, ok, File#file{eof = Pos + iolist_size(FinalBin)}};
+handle_call({write_header, Bin}, _From, #file{} = File) ->
+ case write_header_int(File, Bin) of
+ {ok, File1} ->
+ {reply, ok, File1};
Error ->
{reply, Error, reset_eof(File)}
end;
@@ -700,6 +697,22 @@ load_header(#file{} = File, Pos, HeaderLen, RestBlock) ->
Md5Sig = couch_hash:md5_hash(HeaderBin),
{ok, HeaderBin}.
+write_header_int(#file{eof = Pos} = File, Bin) ->
+ BinSize = byte_size(Bin),
+ case Pos rem ?SIZE_BLOCK of
+ 0 ->
+ Padding = <<>>;
+ BlockOffset ->
+ Padding = <<0:(8 * (?SIZE_BLOCK - BlockOffset))>>
+ end,
+ FinalBin = [Padding, <<1, BinSize:32/integer>> | make_blocks(5, [Bin])],
+ case encrypted_write(File, FinalBin) of
+ ok ->
+ {ok, File#file{eof = Pos + iolist_size(FinalBin)}};
+ Else ->
+ Else
+ end.
+
%% Read multiple block locations using a single file:pread/2.
-spec find_header(file:fd(), block_id(), non_neg_integer()) ->
{ok, binary()} | no_valid_header.
@@ -928,29 +941,43 @@ reset_eof(#file{} = File) ->
File#file{eof = Eof}.
-%% we've wiped all the data, including the wrapped key, so we need a new one.
-init_crypto(#file{eof = 0} = File) ->
+%% new file or we've wiped all the data, including the wrapped key, so we need a new one.
+init_crypto(#file{eof = 0} = File0) ->
Key = crypto:strong_rand_bytes(32),
- WrappedKey = aegis:wrap_key(master_key(), [], Key),
- Header = <<?ENCRYPTED_HEADER, WrappedKey/binary>>,
- ok = file:write(File#file.fd, Header),
- ok = file:sync(File#file.fd),
- {ok, init_crypto(File#file{eof = iolist_size(Header)}, Key)};
+ {WrappingKeyId, WrappingKey} = current_wrapping_key(),
+ WrappedKey = aegis:wrap_key(WrappingKey, [WrappingKeyId], Key),
+ Header = #encryption_header{
+ wrapping_key_id = WrappingKeyId,
+ wrapped_key = WrappedKey
+ },
+ HeaderBin = term_to_binary(Header),
+ Md5 = couch_hash:md5_hash(HeaderBin),
+ FinalBin = <<Md5/binary, HeaderBin/binary>>,
+ case write_header_int(File0#file{enc = unencrypted}, FinalBin) of
+ {ok, File1} ->
+ ok = file:sync(File1#file.fd),
+ {ok, init_crypto(File1, Key)};
+ Else ->
+ Else
+ end;
%% we're opening an existing file and need to unwrap the key.
init_crypto(#file{enc = undefined, dec = undefined} = File) ->
- case file:pread(File#file.fd, 0, 64) of
- {ok, <<?ENCRYPTED_HEADER, WrappedKey:48/binary>>} ->
- case aegis:unwrap_key(master_key(), [], WrappedKey) of
+ {ok, HeaderBin} = load_header(File#file{dec = unencrypted}, 0),
+ case binary_to_term(HeaderBin, [safe]) of
+ #encryption_header{
+ version = 1,
+ wrapping_key_id = WrappingKeyId,
+ wrapped_key = WrappedKey
+ } ->
+ case aegis:unwrap_key(wrapping_key(WrappingKeyId), [WrappingKeyId], WrappedKey) of
fail ->
{error, unwrap_failed};
Key when is_binary(Key) ->
{ok, init_crypto(File, Key)}
end;
- {ok, _} ->
- {ok, File#file{enc = unencrypted, dec = unencrypted}};
- Else ->
- Else
+ _ ->
+ {ok, File#file{enc = unencrypted, dec = unencrypted}}
end;
%% we're opening an existing file that contains a wrapped key
@@ -1027,27 +1054,23 @@ unpad(Pos, Bin) when is_binary(Bin) ->
Result.
-master_key() ->
- couch_pbkdf2:pbkdf2(sha256, master_password(), master_salt(), 100000).
+current_wrapping_key() ->
+ KeyId = config:get("encryption", "wrapping_key_id"),
+ {?l2b(KeyId), wrapping_key(KeyId)}.
-master_password() ->
- case config:get("couchdb", "encryption_password") of
- undefined ->
- undefined;
- Password ->
- ?l2b(Password)
- end.
+wrapping_key(KeyId) ->
+ get_config_binary("encryption_keys", couch_util:to_list(KeyId), undefined).
-master_salt() ->
- case config:get("couchdb", "encryption_salt") of
+
+get_config_binary(Section, Key, Default) ->
+ case config:get(Section, Key) of
undefined ->
- undefined;
- Salt ->
- ?l2b(Salt)
+ Default;
+ Value ->
+ ?l2b(Value)
end.
-
-ifdef(TEST).
-include_lib("couch/include/couch_eunit.hrl").