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From: Jakub Witczak <kuba@erlang.org>
Date: Mon, 24 Mar 2025 11:31:39 +0100
Subject: ssh: custom_kexinit test added
The test uses big KEX init packet which causes large memory
consumption for Erlang prior to 25.3.2.19
Origin: https://github.com/erlang/otp/commit/5ee26eb412a76ba1c6afdf4524b62939a48d1bce
Bug-Debian: https://bugs.debian.org/1101713
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2025-30211
--- a/lib/ssh/test/ssh_protocol_SUITE.erl
+++ b/lib/ssh/test/ssh_protocol_SUITE.erl
@@ -72,6 +72,7 @@
modify_rm/1,
no_common_alg_client_disconnects/1,
no_common_alg_server_disconnects/1,
+ custom_kexinit/1,
no_ext_info_s1/1,
no_ext_info_s2/1,
packet_length_too_large/1,
@@ -132,7 +133,8 @@
{field_size_error, [], [service_name_length_too_large,
service_name_length_too_short]},
- {kex, [], [no_common_alg_server_disconnects,
+ {kex, [], [custom_kexinit,
+ no_common_alg_server_disconnects,
no_common_alg_client_disconnects,
gex_client_init_option_groups,
gex_server_gex_limit,
@@ -173,7 +175,7 @@
end_per_suite(Config) ->
stop_apps(Config).
-init_per_testcase(no_common_alg_server_disconnects, Config) ->
+init_per_testcase(Tc, Config) when Tc == no_common_alg_server_disconnects; Tc == custom_kexinit ->
start_std_daemon(Config, [{preferred_algorithms,[{public_key,['ssh-rsa']},
{cipher,?DEFAULT_CIPHERS}
]}]);
@@ -219,7 +221,7 @@
init_per_testcase(_TestCase, Config) ->
check_std_daemon_works(Config, ?LINE).
-end_per_testcase(no_common_alg_server_disconnects, Config) ->
+end_per_testcase(Tc, Config) when Tc == no_common_alg_server_disconnects; Tc == custom_kexinit ->
stop_std_daemon(Config);
end_per_testcase(kex_strict_negotiated, Config) ->
Config;
@@ -380,6 +382,88 @@
]
).
+custom_kexinit(Config) ->
+ %% 16#C0 value causes unicode:characters_to_list to return a big error value
+ Trash = lists:duplicate(260_000, 16#C0),
+ FunnyAlg = "curve25519-sha256",
+ KexInit =
+ #ssh_msg_kexinit{cookie = <<"Ã/Ï!9zñKá:ñÀv¿JÜ">>,
+ kex_algorithms =
+ [FunnyAlg ++ Trash],
+ server_host_key_algorithms = ["ssh-rsa"],
+ encryption_algorithms_client_to_server =
+ ["aes256-ctr","aes192-ctr","aes128-ctr","aes128-cbc","3des-cbc"],
+ encryption_algorithms_server_to_client =
+ ["aes256-ctr","aes192-ctr","aes128-ctr","aes128-cbc","3des-cbc"],
+ mac_algorithms_client_to_server =
+ ["hmac-sha2-512-etm@openssh.com","hmac-sha2-256-etm@openssh.com",
+ "hmac-sha2-512","hmac-sha2-256","hmac-sha1-etm@openssh.com","hmac-sha1"],
+ mac_algorithms_server_to_client =
+ ["hmac-sha2-512-etm@openssh.com","hmac-sha2-256-etm@openssh.com",
+ "hmac-sha2-512","hmac-sha2-256","hmac-sha1-etm@openssh.com","hmac-sha1"],
+ compression_algorithms_client_to_server = ["none","zlib@openssh.com","zlib"],
+ compression_algorithms_server_to_client = ["none","zlib@openssh.com","zlib"],
+ languages_client_to_server = [],
+ languages_server_to_client = [],
+ first_kex_packet_follows = false,
+ reserved = 0
+ },
+ PacketFun =
+ fun(Msg, Ssh) ->
+ BinMsg = custom_encode(Msg),
+ ssh_transport:pack(BinMsg, Ssh, 0)
+ end,
+ {ok,_} =
+ ssh_trpt_test_lib:exec(
+ [{set_options, [print_ops, {print_messages,detail}]},
+ {connect,
+ server_host(Config),server_port(Config),
+ [{silently_accept_hosts, true},
+ {user_dir, user_dir(Config)},
+ {user_interaction, false},
+ {preferred_algorithms,[{public_key,['ssh-rsa']},
+ {cipher,?DEFAULT_CIPHERS}
+ ]}
+ ]},
+ receive_hello,
+ {send, hello},
+ {match, #ssh_msg_kexinit{_='_'}, receive_msg},
+ {send, {special, KexInit, PacketFun}}, % with server unsupported 'ssh-dss' !
+ {match, disconnect(), receive_msg}
+ ]
+ ).
+
+custom_encode(#ssh_msg_kexinit{
+ cookie = Cookie,
+ kex_algorithms = KeyAlgs,
+ server_host_key_algorithms = HostKeyAlgs,
+ encryption_algorithms_client_to_server = EncAlgC2S,
+ encryption_algorithms_server_to_client = EncAlgS2C,
+ mac_algorithms_client_to_server = MacAlgC2S,
+ mac_algorithms_server_to_client = MacAlgS2C,
+ compression_algorithms_client_to_server = CompAlgS2C,
+ compression_algorithms_server_to_client = CompAlgC2S,
+ languages_client_to_server = LangC2S,
+ languages_server_to_client = LangS2C,
+ first_kex_packet_follows = Bool,
+ reserved = Reserved
+ }) ->
+ KeyAlgsBin0 = <<?Ename_list(KeyAlgs)>>,
+ <<?UINT32(Len0), Data:Len0/binary>> = KeyAlgsBin0,
+ KeyAlgsBin = <<?UINT32(Len0), Data/binary>>,
+ <<?Ebyte(?SSH_MSG_KEXINIT), Cookie/binary,
+ KeyAlgsBin/binary,
+ ?Ename_list(HostKeyAlgs),
+ ?Ename_list(EncAlgC2S),
+ ?Ename_list(EncAlgS2C),
+ ?Ename_list(MacAlgC2S),
+ ?Ename_list(MacAlgS2C),
+ ?Ename_list(CompAlgS2C),
+ ?Ename_list(CompAlgC2S),
+ ?Ename_list(LangC2S),
+ ?Ename_list(LangS2C),
+ ?Eboolean(Bool), ?Euint32(Reserved)>>.
+
%%--------------------------------------------------------------------
%%% Algo negotiation fail. This should result in a ssh_msg_disconnect
%%% being sent from the client.
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