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authorMagnus Henoch <[email protected]>2015-12-08 18:23:42 +0000
committerMagnus Henoch <[email protected]>2016-04-05 15:21:01 +0100
commitb219dbd698c74cf3c904445d13bb3453be6e1ac8 (patch)
tree479d612caf5945c4b866ced0a9f14c29d5ed5d8b /lib
parentee2178b073e936760b405b338e473236a5df94ca (diff)
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Add ssl_crl_hash_dir module
This module is an implementation of the ssl_crl_cache_api behaviour. It can be used when there is a directory containing CRLs for all relevant CAs, in the form used by e.g. Apache. The module assumes that the directory is being updated through an external process.
Diffstat (limited to 'lib')
-rw-r--r--lib/ssl/doc/src/ssl.xml60
-rw-r--r--lib/ssl/src/Makefile1
-rw-r--r--lib/ssl/src/ssl.app.src1
-rw-r--r--lib/ssl/src/ssl_crl_hash_dir.erl106
-rw-r--r--lib/ssl/test/make_certs.erl6
-rw-r--r--lib/ssl/test/ssl_crl_SUITE.erl201
6 files changed, 355 insertions, 20 deletions
diff --git a/lib/ssl/doc/src/ssl.xml b/lib/ssl/doc/src/ssl.xml
index a1fba5fbff..31f88f3285 100644
--- a/lib/ssl/doc/src/ssl.xml
+++ b/lib/ssl/doc/src/ssl.xml
@@ -360,15 +360,59 @@ marker="public_key:public_key#pkix_path_validation-3">public_key:pkix_path_valid
<p>Specify how to perform lookup and caching of certificate revocation lists.
<c>Module</c> defaults to <seealso marker="ssl:ssl_crl_cache">ssl_crl_cache</seealso>
with <c> DbHandle </c> being <c>internal</c> and an
- empty argument list. The following arguments may be specified for the internal cache:</p>
+ empty argument list.</p>
+
+ <p>There are two implementations available:</p>
+
<taglist>
- <tag><c>{http, timeout()}</c></tag>
- <item><p>
- Enables fetching of CRLs specified as http URIs in<seealso
- marker="public_key:public_key_records"> X509 certificate extensions.</seealso>
- Requires the OTP inets application.</p>
- </item>
- </taglist>
+ <tag><c>ssl_crl_cache</c></tag>
+ <item>
+ <p>This module maintains a cache of CRLs. CRLs can be
+ added to the cache using the function <seealso
+ marker="ssl:ssl_crl_cache#insert-1">ssl_crl_cache:insert/1</seealso>,
+ and optionally automatically fetched through HTTP if the
+ following argument is specified:</p>
+
+ <taglist>
+ <tag><c>{http, timeout()}</c></tag>
+ <item><p>
+ Enables fetching of CRLs specified as http URIs in<seealso
+ marker="public_key:public_key_records">X509 certificate extensions</seealso>.
+ Requires the OTP inets application.</p>
+ </item>
+ </taglist>
+ </item>
+
+ <tag><c>ssl_crl_hash_dir</c></tag>
+ <item>
+ <p>This module makes use of a directory where CRLs are
+ stored in files named by the hash of the issuer name.</p>
+
+ <p>The file names consist of eight hexadecimal digits
+ followed by <c>.rN</c>, where <c>N</c> is an integer,
+ e.g. <c>1a2b3c4d.r0</c>. For the first version of the
+ CRL, <c>N</c> starts at zero, and for each new version,
+ <c>N</c> is incremented by one. The OpenSSL utility
+ <c>c_rehash</c> creates symlinks according to this
+ pattern.</p>
+
+ <p>For a given hash value, this module finds all
+ consecutive <c>.r*</c> files starting from zero, and those
+ files taken together make up the revocation list. CRL
+ files whose <c>nextUpdate</c> fields are in the past, or
+ that are issued by a different CA that happens to have the
+ same name hash, are excluded.</p>
+
+ <p>The following argument is required:</p>
+
+ <taglist>
+ <tag><c>{dir, string()}</c></tag>
+ <item><p>Specifies the directory in which the CRLs can be found.</p></item>
+ </taglist>
+
+ </item>
+ </taglist>
+
</item>
<tag><c>{partial_chain, fun(Chain::[DerCert]) -> {trusted_ca, DerCert} |
diff --git a/lib/ssl/src/Makefile b/lib/ssl/src/Makefile
index 7a7a373487..b625db0656 100644
--- a/lib/ssl/src/Makefile
+++ b/lib/ssl/src/Makefile
@@ -70,6 +70,7 @@ MODULES= \
ssl_session_cache \
ssl_crl\
ssl_crl_cache \
+ ssl_crl_hash_dir \
ssl_socket \
ssl_listen_tracker_sup \
tls_record \
diff --git a/lib/ssl/src/ssl.app.src b/lib/ssl/src/ssl.app.src
index 1a2bf90ccf..5aa399201a 100644
--- a/lib/ssl/src/ssl.app.src
+++ b/lib/ssl/src/ssl.app.src
@@ -44,6 +44,7 @@
ssl_crl,
ssl_crl_cache,
ssl_crl_cache_api,
+ ssl_crl_hash_dir,
%% App structure
ssl_app,
ssl_sup,
diff --git a/lib/ssl/src/ssl_crl_hash_dir.erl b/lib/ssl/src/ssl_crl_hash_dir.erl
new file mode 100644
index 0000000000..bb62737232
--- /dev/null
+++ b/lib/ssl/src/ssl_crl_hash_dir.erl
@@ -0,0 +1,106 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2016-2016. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+
+-module(ssl_crl_hash_dir).
+
+-include_lib("public_key/include/public_key.hrl").
+
+-behaviour(ssl_crl_cache_api).
+
+-export([lookup/3, select/2, fresh_crl/2]).
+
+lookup(#'DistributionPoint'{cRLIssuer = CRLIssuer} = DP, CertIssuer, CRLDbInfo) ->
+ Issuer =
+ case CRLIssuer of
+ asn1_NOVALUE ->
+ %% If the distribution point extension doesn't
+ %% indicate a CRL issuer, use the certificate issuer.
+ CertIssuer;
+ _ ->
+ CRLIssuer
+ end,
+ %% Find all CRLs for this issuer, and return those that match the
+ %% given distribution point.
+ AllCRLs = select(Issuer, CRLDbInfo),
+ lists:filter(fun(DER) ->
+ public_key:pkix_match_dist_point(DER, DP)
+ end, AllCRLs).
+
+fresh_crl(#'DistributionPoint'{}, CurrentCRL) ->
+ CurrentCRL.
+
+select(Issuer, {_DbHandle, [{dir, Dir}]}) ->
+ case find_crls(Issuer, Dir) of
+ [_|_] = DERs ->
+ DERs;
+ [] ->
+ %% That's okay, just report that we didn't find any CRL.
+ %% If the crl_check setting is best_effort, ssl_handshake
+ %% is happy with that, but if it's true, this is an error.
+ [];
+ {error, Error} ->
+ error_logger:error_report(
+ [{cannot_find_crl, Error},
+ {dir, Dir},
+ {module, ?MODULE},
+ {line, ?LINE}]),
+ []
+ end.
+
+find_crls(Issuer, Dir) ->
+ case filelib:is_dir(Dir) of
+ true ->
+ Hash = public_key:short_name_hash(Issuer),
+ find_crls(Issuer, Hash, Dir, 0, []);
+ false ->
+ {error, not_a_directory}
+ end.
+
+find_crls(Issuer, Hash, Dir, N, Acc) ->
+ Filename = filename:join(Dir, Hash ++ ".r" ++ integer_to_list(N)),
+ case file:read_file(Filename) of
+ {error, enoent} ->
+ Acc;
+ {ok, Bin} ->
+ try maybe_parse_pem(Bin) of
+ DER when is_binary(DER) ->
+ %% Found one file. Let's see if there are more.
+ find_crls(Issuer, Hash, Dir, N + 1, [DER] ++ Acc)
+ catch
+ error:Error ->
+ %% Something is wrong with the file. Report
+ %% it, and try the next one.
+ error_logger:error_report(
+ [{crl_parse_error, Error},
+ {filename, Filename},
+ {module, ?MODULE},
+ {line, ?LINE}]),
+ find_crls(Issuer, Hash, Dir, N + 1, Acc)
+ end
+ end.
+
+maybe_parse_pem(<<"-----BEGIN", _/binary>> = PEM) ->
+ %% It's a PEM encoded file. Need to extract the DER
+ %% encoded data.
+ [{'CertificateList', DER, not_encrypted}] = public_key:pem_decode(PEM),
+ DER;
+maybe_parse_pem(DER) when is_binary(DER) ->
+ %% Let's assume it's DER-encoded.
+ DER.
+
diff --git a/lib/ssl/test/make_certs.erl b/lib/ssl/test/make_certs.erl
index 5eebf773a7..ed1a6523ed 100644
--- a/lib/ssl/test/make_certs.erl
+++ b/lib/ssl/test/make_certs.erl
@@ -172,11 +172,15 @@ revoke(Root, CA, User, C) ->
gencrl(Root, CA, C).
gencrl(Root, CA, C) ->
+ %% By default, the CRL is valid for 24 hours from now.
+ gencrl(Root, CA, C, 24).
+
+gencrl(Root, CA, C, CrlHours) ->
CACnfFile = filename:join([Root, CA, "ca.cnf"]),
CACRLFile = filename:join([Root, CA, "crl.pem"]),
Cmd = [C#config.openssl_cmd, " ca"
" -gencrl ",
- " -crlhours 24",
+ " -crlhours ", integer_to_list(CrlHours),
" -out ", CACRLFile,
" -config ", CACnfFile],
Env = [{"ROOTDIR", filename:absname(Root)}],
diff --git a/lib/ssl/test/ssl_crl_SUITE.erl b/lib/ssl/test/ssl_crl_SUITE.erl
index 5b86027210..27005682e9 100644
--- a/lib/ssl/test/ssl_crl_SUITE.erl
+++ b/lib/ssl/test/ssl_crl_SUITE.erl
@@ -41,20 +41,26 @@ groups() ->
[
{check_true, [], [{group, v2_crl},
{group, v1_crl},
- {group, idp_crl}]},
+ {group, idp_crl},
+ {group, crl_hash_dir}]},
{check_peer, [], [{group, v2_crl},
{group, v1_crl},
- {group, idp_crl}]},
+ {group, idp_crl},
+ {group, crl_hash_dir}]},
{check_best_effort, [], [{group, v2_crl},
{group, v1_crl},
- {group, idp_crl}]},
+ {group, idp_crl},
+ {group, crl_hash_dir}]},
{v2_crl, [], basic_tests()},
{v1_crl, [], basic_tests()},
- {idp_crl, [], basic_tests()}].
+ {idp_crl, [], basic_tests()},
+ {crl_hash_dir, [], basic_tests() ++ crl_hash_dir_tests()}].
basic_tests() ->
[crl_verify_valid, crl_verify_revoked, crl_verify_no_crl].
+crl_hash_dir_tests() ->
+ [crl_hash_dir_collision, crl_hash_dir_expired].
init_per_suite(Config) ->
case os:find_executable("openssl") of
@@ -101,7 +107,24 @@ init_per_group(Group, Config0) ->
CertDir = filename:join(?config(priv_dir, Config0), Group),
{CertOpts, Config} = init_certs(CertDir, Group, Config0),
{ok, _} = make_certs:all(DataDir, CertDir, CertOpts),
- [{cert_dir, CertDir}, {idp_crl, false} | Config]
+ case Group of
+ crl_hash_dir ->
+ CrlDir = filename:join(CertDir, "crls"),
+ %% Copy CRLs to their hashed filenames.
+ %% Find the hashes with 'openssl crl -noout -hash -in crl.pem'.
+ populate_crl_hash_dir(CertDir, CrlDir,
+ [{"erlangCA", "d6134ed3"},
+ {"otpCA", "d4c8d7e5"}],
+ replace),
+ CrlCacheOpts = [{crl_cache,
+ {ssl_crl_hash_dir,
+ {internal, [{dir, CrlDir}]}}}];
+ _ ->
+ CrlCacheOpts = []
+ end,
+ [{crl_cache_opts, CrlCacheOpts},
+ {cert_dir, CertDir},
+ {idp_crl, false} | Config]
end.
end_per_group(_GroupName, Config) ->
@@ -164,9 +187,10 @@ crl_verify_valid(Config) when is_list(Config) ->
{crl_cache, {ssl_crl_cache, {internal, [{http, 5000}]}}},
{verify, verify_peer}];
false ->
- [{cacertfile, filename:join([PrivDir, "server", "cacerts.pem"])},
- {crl_check, Check},
- {verify, verify_peer}]
+ ?config(crl_cache_opts, Config) ++
+ [{cacertfile, filename:join([PrivDir, "server", "cacerts.pem"])},
+ {crl_check, Check},
+ {verify, verify_peer}]
end,
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
@@ -196,9 +220,10 @@ crl_verify_revoked(Config) when is_list(Config) ->
{crl_check, Check},
{verify, verify_peer}];
false ->
- [{cacertfile, filename:join([PrivDir, "revoked", "cacerts.pem"])},
- {crl_check, Check},
- {verify, verify_peer}]
+ ?config(crl_cache_opts, Config) ++
+ [{cacertfile, filename:join([PrivDir, "revoked", "cacerts.pem"])},
+ {crl_check, Check},
+ {verify, verify_peer}]
end,
crl_verify_error(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts,
@@ -251,6 +276,132 @@ crl_verify_no_crl(Config) when is_list(Config) ->
crl_verify_valid(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts)
end.
+crl_hash_dir_collision() ->
+ [{doc,"Verify ssl_crl_hash_dir behaviour with hash collisions"}].
+crl_hash_dir_collision(Config) when is_list(Config) ->
+ PrivDir = ?config(cert_dir, Config),
+ Check = ?config(crl_check, Config),
+
+ %% Create two CAs whose names hash to the same value
+ CA1 = "hash-collision-0000000000",
+ CA2 = "hash-collision-0258497583",
+ CertsConfig = make_certs:make_config([]),
+ make_certs:intermediateCA(PrivDir, CA1, "erlangCA", CertsConfig),
+ make_certs:intermediateCA(PrivDir, CA2, "erlangCA", CertsConfig),
+
+ make_certs:enduser(PrivDir, CA1, "collision-client-1", CertsConfig),
+ make_certs:enduser(PrivDir, CA2, "collision-client-2", CertsConfig),
+
+ [ServerOpts1, ServerOpts2] =
+ [
+ [{keyfile, filename:join([PrivDir, EndUser, "key.pem"])},
+ {certfile, filename:join([PrivDir, EndUser, "cert.pem"])},
+ {cacertfile, filename:join([PrivDir, EndUser, "cacerts.pem"])}]
+ || EndUser <- ["collision-client-1", "collision-client-2"]],
+
+ %% Add CRLs for our new CAs into the CRL hash directory.
+ %% Find the hashes with 'openssl crl -noout -hash -in crl.pem'.
+ CrlDir = filename:join(PrivDir, "crls"),
+ populate_crl_hash_dir(PrivDir, CrlDir,
+ [{CA1, "b68fc624"},
+ {CA2, "b68fc624"}],
+ replace),
+
+ ClientOpts = ?config(crl_cache_opts, Config) ++
+ [{cacertfile, filename:join([PrivDir, "erlangCA", "cacerts.pem"])},
+ {crl_check, Check},
+ {verify, verify_peer}],
+
+ {ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
+
+ %% Neither certificate revoked; both succeed.
+ crl_verify_valid(Hostname, ServerNode, ServerOpts1, ClientNode, ClientOpts),
+ crl_verify_valid(Hostname, ServerNode, ServerOpts2, ClientNode, ClientOpts),
+
+ make_certs:revoke(PrivDir, CA1, "collision-client-1", CertsConfig),
+ populate_crl_hash_dir(PrivDir, CrlDir,
+ [{CA1, "b68fc624"},
+ {CA2, "b68fc624"}],
+ replace),
+
+ %% First certificate revoked; first fails, second succeeds.
+ crl_verify_error(Hostname, ServerNode, ServerOpts1, ClientNode, ClientOpts,
+ "certificate revoked"),
+ crl_verify_valid(Hostname, ServerNode, ServerOpts2, ClientNode, ClientOpts),
+
+ make_certs:revoke(PrivDir, CA2, "collision-client-2", CertsConfig),
+ populate_crl_hash_dir(PrivDir, CrlDir,
+ [{CA1, "b68fc624"},
+ {CA2, "b68fc624"}],
+ replace),
+
+ %% Second certificate revoked; both fail.
+ crl_verify_error(Hostname, ServerNode, ServerOpts1, ClientNode, ClientOpts,
+ "certificate revoked"),
+ crl_verify_error(Hostname, ServerNode, ServerOpts2, ClientNode, ClientOpts,
+ "certificate revoked"),
+
+ ok.
+
+crl_hash_dir_expired() ->
+ [{doc,"Verify ssl_crl_hash_dir behaviour with expired CRLs"}].
+crl_hash_dir_expired(Config) when is_list(Config) ->
+ PrivDir = ?config(cert_dir, Config),
+ Check = ?config(crl_check, Config),
+
+ CA = "CRL-maybe-expired-CA",
+ %% Add "issuing distribution point", to ensure that verification
+ %% fails if there is no valid CRL.
+ CertsConfig = make_certs:make_config([{issuing_distribution_point, true}]),
+ make_certs:intermediateCA(PrivDir, CA, "erlangCA", CertsConfig),
+ EndUser = "CRL-maybe-expired",
+ make_certs:enduser(PrivDir, CA, EndUser, CertsConfig),
+
+ ServerOpts = [{keyfile, filename:join([PrivDir, EndUser, "key.pem"])},
+ {certfile, filename:join([PrivDir, EndUser, "cert.pem"])},
+ {cacertfile, filename:join([PrivDir, EndUser, "cacerts.pem"])}],
+ ClientOpts = ?config(crl_cache_opts, Config) ++
+ [{cacertfile, filename:join([PrivDir, CA, "cacerts.pem"])},
+ {crl_check, Check},
+ {verify, verify_peer}],
+ {ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
+
+ %% First make a CRL that expired yesterday.
+ make_certs:gencrl(PrivDir, CA, CertsConfig, -24),
+ CrlDir = filename:join(PrivDir, "crls"),
+ populate_crl_hash_dir(PrivDir, CrlDir,
+ [{CA, "1627b4b0"}],
+ replace),
+
+ %% Since the CRL has expired, it's treated as missing, and the
+ %% outcome depends on the crl_check setting.
+ case Check of
+ true ->
+ %% The error "revocation status undetermined" gets turned
+ %% into "bad certificate".
+ crl_verify_error(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts,
+ "bad certificate");
+ peer ->
+ crl_verify_error(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts,
+ "bad certificate");
+ best_effort ->
+ %% In "best effort" mode, we consider the certificate not
+ %% to be revoked if we can't find the appropriate CRL.
+ crl_verify_valid(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts)
+ end,
+
+ %% Now make a CRL that expires tomorrow.
+ make_certs:gencrl(PrivDir, CA, CertsConfig, 24),
+ CrlDir = filename:join(PrivDir, "crls"),
+ populate_crl_hash_dir(PrivDir, CrlDir,
+ [{CA, "1627b4b0"}],
+ add),
+
+ %% With a valid CRL, verification should always pass.
+ crl_verify_valid(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts),
+
+ ok.
+
crl_verify_valid(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts) ->
Server = ssl_test_lib:start_server([{node, ServerNode}, {port, 0},
{from, self()},
@@ -311,3 +462,31 @@ make_dir_path(PathComponents) ->
rename_crl(Filename) ->
file:rename(Filename, Filename ++ ".notfound").
+
+populate_crl_hash_dir(CertDir, CrlDir, CAsHashes, AddOrReplace) ->
+ ok = filelib:ensure_dir(filename:join(CrlDir, "crls")),
+ case AddOrReplace of
+ replace ->
+ %% Delete existing files, so we can override them.
+ [ok = file:delete(FileToDelete) ||
+ {_CA, Hash} <- CAsHashes,
+ FileToDelete <- filelib:wildcard(
+ filename:join(CrlDir, Hash ++ ".r*"))];
+ add ->
+ ok
+ end,
+ %% Create new files, incrementing suffix if needed to find unique names.
+ [{ok, _} =
+ file:copy(filename:join([CertDir, CA, "crl.pem"]),
+ find_free_name(CrlDir, Hash, 0))
+ || {CA, Hash} <- CAsHashes],
+ ok.
+
+find_free_name(CrlDir, Hash, N) ->
+ Name = filename:join(CrlDir, Hash ++ ".r" ++ integer_to_list(N)),
+ case filelib:is_file(Name) of
+ true ->
+ find_free_name(CrlDir, Hash, N + 1);
+ false ->
+ Name
+ end.