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Improve basic auth credentials handling in replicator
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Previously, there were two ways to pass in basic auth credentials for
endpoints -- using URL's userinfo part and encoding the them in an
`"Authorization": "basic ..."` header. Neither one is ideal for these reasons:

 * Passwords in userinfo doesn't allow using ":", "@" and other characters.
   However, even after switching to always unquoting them like we did recently
   [1], would break authentication for usernames or passwords previously
   containing "+" or "%HH" patterns, as "+" might now be decoded to a " ".

 * Base64 encoded headers need an extra step to encode them. Also, quite often
   these encoded headers are confused as being "encrypted" and shared in a
   clear channel.

To improve this, revert the recent commit to unquote URL userinfo parts to
restore backwards compatibility, and introduce a way to pass in basic auth
credentials in the "auth" object. The "auth" object was already added a while
back to allow authentication plugins to store their credentials in it. The
format is:

```
   "source": {
       "url": "https://host/db",
       "auth": {
           "basic": {
               "username":"myuser",
               "password":"mypassword"
           }
       }
   }
```

{"auth" : "basic" : {...}} object is checked first, and if credentials are
provided, they will be used. If they are not then userinfo and basic auth
header will be parsed.

Internally, there was a good amount duplication related to parsing credentials
from userinfo and headers in replication ID generation logic and in the auth
session plugin. As a cleanup, consolidate that logic in the
`couch_replicator_utils` module.

[1] f672b91
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@nickva
nickva committed Jun 1, 2021
1 parent 0bd9465 commit ecd266b
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Showing 7 changed files with 353 additions and 225 deletions.
10 changes: 5 additions & 5 deletions src/couch_replicator/src/couch_replicator.erl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -373,21 +373,21 @@ t_strip_local_db_creds() ->
t_strip_http_basic_creds() ->
?_test(begin
Url1 = <<"http://adm:pass@host/db">>,
?assertEqual(<<"http://adm:*****@host/db/">>, strip_url_creds(Url1)),
?assertEqual(<<"http://host/db/">>, strip_url_creds(Url1)),
Url2 = <<"https://adm:pass@host/db">>,
?assertEqual(<<"https://adm:*****@host/db/">>, strip_url_creds(Url2)),
?assertEqual(<<"https://host/db/">>, strip_url_creds(Url2)),
Url3 = <<"http://adm:pass@host:80/db">>,
?assertEqual(<<"http://adm:*****@host:80/db/">>, strip_url_creds(Url3)),
?assertEqual(<<"http://host:80/db/">>, strip_url_creds(Url3)),
Url4 = <<"http://adm:pass@host/db?a=b&c=d">>,
?assertEqual(<<"http://adm:*****@host/db?a=b&c=d">>,
?assertEqual(<<"http://host/db?a=b&c=d">>,
strip_url_creds(Url4))
end).


t_strip_http_props_creds() ->
?_test(begin
Props1 = {[{<<"url">>, <<"http://adm:pass@host/db">>}]},
?assertEqual(<<"http://adm:*****@host/db/">>, strip_url_creds(Props1)),
?assertEqual(<<"http://host/db/">>, strip_url_creds(Props1)),
Props2 = {[ {<<"url">>, <<"http://host/db">>},
{<<"headers">>, {[{<<"Authorization">>, <<"Basic pa55">>}]}}
]},
Expand Down
204 changes: 27 additions & 177 deletions src/couch_replicator/src/couch_replicator_auth_session.erl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,6 @@

-type headers() :: [{string(), string()}].
-type code() :: non_neg_integer().
-type creds() :: {string() | undefined, string() | undefined}.
-type time_sec() :: non_neg_integer().
-type age() :: time_sec() | undefined.

Expand Down Expand Up @@ -238,59 +237,15 @@ init_state(#httpdb{} = HttpDb) ->

-spec extract_creds(#httpdb{}) ->
{ok, string(), string(), #httpdb{}} | {error, term()}.
extract_creds(#httpdb{url = Url, headers = Headers} = HttpDb) ->
{{HeadersUser, HeadersPass}, HeadersNoCreds} =
couch_replicator_utils:remove_basic_auth_from_headers(Headers),
case extract_creds_from_url(Url) of
{ok, UrlUser, UrlPass, UrlNoCreds} ->
case pick_creds({UrlUser, UrlPass}, {HeadersUser, HeadersPass}) of
{ok, User, Pass} ->
HttpDb1 = HttpDb#httpdb{
url = UrlNoCreds,
headers = HeadersNoCreds
},
{ok, User, Pass, HttpDb1};
{error, Error} ->
{error, Error}
end;
{error, Error} ->
{error, Error}
end.


% Credentials could be specified in the url and/or in the headers.
% * If no credentials specified return error.
% * If specified in url but not in headers, pick url creds.
% * Otherwise pick headers creds.
%
-spec pick_creds(creds(), creds()) ->
{ok, string(), string()} | {error, missing_credentials}.
pick_creds({undefined, _}, {undefined, _}) ->
{error, missing_credentials};
pick_creds({UrlUser, UrlPass}, {undefined, _}) ->
{ok, UrlUser, UrlPass};
pick_creds({_, _}, {HeadersUser, HeadersPass}) ->
{ok, HeadersUser, HeadersPass}.


-spec extract_creds_from_url(string()) ->
{ok, string() | undefined, string() | undefined, string()} |
{error, term()}.
extract_creds_from_url(Url) ->
case ibrowse_lib:parse_url(Url) of
{error, Error} ->
{error, Error};
#url{username = undefined, password = undefined} ->
{ok, undefined, undefined, Url};
#url{protocol = Proto, username = User, password = Pass} ->
% Excise user and pass parts from the url. Try to keep the host,
% port and path as they were in the original.
Prefix = lists:concat([Proto, "://", User, ":", Pass, "@"]),
Suffix = lists:sublist(Url, length(Prefix) + 1, length(Url) + 1),
NoCreds = lists:concat([Proto, "://", Suffix]),
User1 = chttpd:unquote(User),
Pass1 = chttpd:unquote(Pass),
{ok, User1, Pass1, NoCreds}
extract_creds(#httpdb{} = HttpDb) ->
case couch_replicator_utils:get_basic_auth_creds(HttpDb) of
{undefined, undefined} ->
% Return error. Session plugin should ignore this replication
% endpoint as there are no valid creds which can be used
{error, missing_credentials};
{User, Pass} when is_list(User), is_list(Pass) ->
HttpDb1 = couch_replicator_utils:remove_basic_auth_creds(HttpDb),
{ok, User, Pass, HttpDb1}
end.


Expand Down Expand Up @@ -569,116 +524,15 @@ get_session_url_test_() ->
]].


extract_creds_success_test_() ->
DefaultHeaders = (#httpdb{})#httpdb.headers,
[?_assertEqual({ok, User, Pass, HttpDb2}, extract_creds(HttpDb1)) ||
{HttpDb1, {User, Pass, HttpDb2}} <- [
{
#httpdb{url = "http://u:p@x.y/db"},
{"u", "p", #httpdb{url = "http://x.y/db"}}
},
{
#httpdb{url = "http://u%40:p%40@x.y/db"},
{"u@", "p@", #httpdb{url = "http://x.y/db"}}
},
{
#httpdb{url = "http://u%40u:p%40p@x.y/db"},
{"u@u", "p@p", #httpdb{url = "http://x.y/db"}}
},
{
#httpdb{url = "http://u%40%401:p%40%401@x.y/db"},
{"u@@1", "p@@1", #httpdb{url = "http://x.y/db"}}
},
{
#httpdb{url = "http://u%40%2540:p%40%2540@x.y/db"},
{"u@%40", "p@%40", #httpdb{url = "http://x.y/db"}}
},
{
#httpdb{url = "http://u:p@h:80/db"},
{"u", "p", #httpdb{url = "http://h:80/db"}}
},
{
#httpdb{url = "http://u%3A:p%3A@h:80/db"},
{"u:", "p:", #httpdb{url = "http://h:80/db"}}
},
{
#httpdb{url = "https://u:p@h/db"},
{"u", "p", #httpdb{url = "https://h/db"}}
},
{
#httpdb{url = "https://u%2F:p%2F@h/db"},
{"u/", "p/", #httpdb{url = "https://h/db"}}
},
{
#httpdb{url = "http://u:p@127.0.0.1:5984/db"},
{"u", "p", #httpdb{url = "http://127.0.0.1:5984/db"}}
},
{
#httpdb{url = "http://u:p@[2001:db8:a1b:12f9::1]/db"},
{"u", "p", #httpdb{url = "http://[2001:db8:a1b:12f9::1]/db"}}
},
{
#httpdb{url = "http://u:p@[2001:db8:a1b:12f9::1]:81/db"},
{"u", "p", #httpdb{url = "http://[2001:db8:a1b:12f9::1]:81/db"}}
},
{
#httpdb{url = "http://u:p%3A%2F%5B%5D%40@[2001:db8:a1b:12f9::1]:81/db"},
{"u", "p:/[]@", #httpdb{url = "http://[2001:db8:a1b:12f9::1]:81/db"}}
},
{
#httpdb{url = "http://u:p@x.y/db/other?query=Z&query=w"},
{"u", "p", #httpdb{url = "http://x.y/db/other?query=Z&query=w"}}
},
{
#httpdb{url = "http://u:p%3F@x.y/db/other?query=Z&query=w"},
{"u", "p?", #httpdb{url = "http://x.y/db/other?query=Z&query=w"}}
},
{
#httpdb{
url = "http://h/db",
headers = DefaultHeaders ++ [
{"Authorization", "Basic " ++ b64creds("u", "p")}
]
},
{"u", "p", #httpdb{url = "http://h/db"}}
},
{
#httpdb{
url = "http://h/db",
headers = DefaultHeaders ++ [
{"Authorization", "Basic " ++ b64creds("u", "p@")}
]
},
{"u", "p@", #httpdb{url = "http://h/db"}}
},
{
#httpdb{
url = "http://h/db",
headers = DefaultHeaders ++ [
{"Authorization", "Basic " ++ b64creds("u", "p@%40")}
]
},
{"u", "p@%40", #httpdb{url = "http://h/db"}}
},
{
#httpdb{
url = "http://h/db",
headers = DefaultHeaders ++ [
{"aUthoriZation", "bASIC " ++ b64creds("U", "p")}
]
},
{"U", "p", #httpdb{url = "http://h/db"}}
},
{
#httpdb{
url = "http://u1:p1@h/db",
headers = DefaultHeaders ++ [
{"Authorization", "Basic " ++ b64creds("u2", "p2")}
]
},
{"u2", "p2", #httpdb{url = "http://h/db"}}
}
]].
extract_creds_success_test() ->
HttpDb = #httpdb{auth_props = [
{<<"basic">>, {[
{<<"username">>, <<"u2">>},
{<<"password">>, <<"p2">>}
]}}
]},
?assertEqual({ok, "u2", "p2", #httpdb{}}, extract_creds(HttpDb)),
?assertEqual({error, missing_credentials}, extract_creds(#httpdb{})).


cookie_update_test_() ->
Expand Down Expand Up @@ -795,7 +649,7 @@ t_process_ok_no_cookie() ->
t_init_state_fails_on_401() ->
?_test(begin
mock_http_401_response(),
{error, Error} = init_state(#httpdb{url = "http://u:p@h"}),
{error, Error} = init_state(httpdb("http://u:p@h")),
SessionUrl = "http://h/_session",
?assertEqual({session_request_unauthorized, SessionUrl, "u"}, Error)
end).
Expand All @@ -805,32 +659,36 @@ t_init_state_401_with_require_valid_user() ->
?_test(begin
mock_http_401_response_with_require_valid_user(),
?assertMatch({ok, #httpdb{}, #state{cookie = "Cookie"}},
init_state(#httpdb{url = "http://u:p@h"}))
init_state(httpdb("http://u:p@h")))
end).


t_init_state_404() ->
?_test(begin
mock_http_404_response(),
?assertEqual(ignore, init_state(#httpdb{url = "http://u:p@h"}))
?assertEqual(ignore, init_state(httpdb("http://u:p@h")))
end).


t_init_state_no_creds() ->
?_test(begin
?_assertEqual(ignore, init_state(#httpdb{url = "http://h"}))
?_assertEqual(ignore, init_state(httpdb("http://h")))
end).


t_init_state_http_error() ->
?_test(begin
mock_http_error_response(),
{error, Error} = init_state(#httpdb{url = "http://u:p@h"}),
{error, Error} = init_state(httpdb("http://u:p@h")),
SessionUrl = "http://h/_session",
?assertEqual({session_request_failed, SessionUrl, "u", x}, Error)
end).


httpdb(Url) ->
couch_replicator_utils:normalize_basic_auth(#httpdb{url = Url}).


setup_all() ->
meck:expect(couch_replicator_httpc_pool, get_worker, 1, {ok, worker}),
meck:expect(couch_replicator_httpc_pool, release_worker_sync, 2, ok),
Expand Down Expand Up @@ -885,14 +743,6 @@ mock_http_error_response() ->
meck:expect(ibrowse, send_req_direct, 7, {error, x}).


extract_creds_error_test_() ->
[?_assertMatch({error, Error}, extract_creds(HttpDb)) ||
{HttpDb, Error} <- [
{#httpdb{url = "some_junk"}, invalid_uri},
{#httpdb{url = "http://h/db"}, missing_credentials}
]].


parse_max_age_test_() ->
[?_assertEqual(R, parse_max_age(mochiweb_headers:make([{"Max-Age", A}])))
|| {A, R} <- [
Expand Down
5 changes: 3 additions & 2 deletions src/couch_replicator/src/couch_replicator_docs.erl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -408,7 +408,7 @@ parse_rep_db({Props}, Proxy, Options) ->
{BinHeaders} = get_value(<<"headers">>, Props, {[]}),
Headers = lists:ukeysort(1, [{?b2l(K), ?b2l(V)} || {K, V} <- BinHeaders]),
DefaultHeaders = (#httpdb{})#httpdb.headers,
#httpdb{
HttpDb = #httpdb{
url = Url,
auth_props = AuthProps,
headers = lists:ukeymerge(1, Headers, DefaultHeaders),
Expand All @@ -419,7 +419,8 @@ parse_rep_db({Props}, Proxy, Options) ->
http_connections = get_value(http_connections, Options),
retries = get_value(retries, Options),
proxy_url = ProxyURL
};
},
couch_replicator_utils:normalize_basic_auth(HttpDb);

parse_rep_db(<<"http://", _/binary>> = Url, Proxy, Options) ->
parse_rep_db({[{<<"url">>, Url}]}, Proxy, Options);
Expand Down
8 changes: 7 additions & 1 deletion src/couch_replicator/src/couch_replicator_httpc.erl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -112,7 +112,13 @@ send_ibrowse_req(#httpdb{headers = BaseHeaders} = HttpDb0, Params) ->
end
end,
{ok, Worker} = couch_replicator_httpc_pool:get_worker(HttpDb#httpdb.httpc_pool),
IbrowseOptions = [
BasicAuthOpts = case couch_replicator_utils:get_basic_auth_creds(HttpDb) of
{undefined, undefined} ->
[];
{User, Pass} when is_list(User), is_list(Pass) ->
[{basic_auth, {User, Pass}}]
end,
IbrowseOptions = BasicAuthOpts ++ [
{response_format, binary}, {inactivity_timeout, HttpDb#httpdb.timeout} |
lists:ukeymerge(1, get_value(ibrowse_options, Params, []),
HttpDb#httpdb.ibrowse_options)
Expand Down

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