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authorHans Nilsson <[email protected]>2018-11-14 12:57:46 +0100
committerHans Nilsson <[email protected]>2018-11-19 17:23:35 +0100
commitb4ad3a9eb7a1b375d2dbbf93069ea9ae038d121f (patch)
tree349407e3ad051220b8cc3a12474022927145bfde
parent709534a5417f20f8edda1d3664669ed9d3129354 (diff)
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ssh: Make host and user key pre-checking better
This will prevent crashes in ssh_file for public key types which have no passphrase option although being supported. Also centralize host key checking to avoid code duplication. This was already done for user keys.
-rw-r--r--lib/ssh/src/ssh_connection_handler.erl50
-rw-r--r--lib/ssh/src/ssh_file.erl3
-rw-r--r--lib/ssh/src/ssh_transport.erl18
3 files changed, 38 insertions, 33 deletions
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index e23df6ceca..7c87591cf2 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -1685,18 +1685,19 @@ peer_role(client) -> server;
peer_role(server) -> client.
%%--------------------------------------------------------------------
-available_hkey_algorithms(Role, Options) ->
- KeyCb = ?GET_OPT(key_cb, Options),
- case [A || A <- available_hkey_algos(Options),
- (Role==client) orelse available_host_key(KeyCb, A, Options)
- ] of
-
- [] when Role==client ->
- error({shutdown, "No public key algs"});
-
- [] when Role==server ->
- error({shutdown, "No host key available"});
+available_hkey_algorithms(client, Options) ->
+ case available_hkey_algos(Options) of
+ [] ->
+ error({shutdown, "No public key algs"});
+ Algs ->
+ [atom_to_list(A) || A<-Algs]
+ end;
+available_hkey_algorithms(server, Options) ->
+ case [A || A <- available_hkey_algos(Options),
+ is_usable_host_key(A, Options)] of
+ [] ->
+ error({shutdown, "No host key available"});
Algs ->
[atom_to_list(A) || A<-Algs]
end.
@@ -1712,18 +1713,6 @@ available_hkey_algos(Options) ->
AvailableAndSupported.
-%% Alg :: atom()
-available_host_key({KeyCb,KeyCbOpts}, Alg, Opts) ->
- UserOpts = ?GET_OPT(user_options, Opts),
- case KeyCb:host_key(Alg, [{key_cb_private,KeyCbOpts}|UserOpts]) of
- {ok,Key} ->
- %% Check the key - the KeyCb may be a buggy plugin
- ssh_transport:valid_key_sha_alg(Key, Alg);
- _ ->
- false
- end.
-
-
send_msg(Msg, State=#data{ssh_params=Ssh0}) when is_tuple(Msg) ->
{Bytes, Ssh} = ssh_transport:ssh_packet(Msg, Ssh0),
send_bytes(Bytes, State),
@@ -1843,10 +1832,21 @@ ext_info(_, D0) ->
D0.
%%%----------------------------------------------------------------
-is_usable_user_pubkey(A, Ssh) ->
- case ssh_auth:get_public_key(A, Ssh) of
+is_usable_user_pubkey(Alg, Ssh) ->
+ try ssh_auth:get_public_key(Alg, Ssh) of
{ok,_} -> true;
_ -> false
+ catch
+ _:_ -> false
+ end.
+
+%%%----------------------------------------------------------------
+is_usable_host_key(Alg, Opts) ->
+ try ssh_transport:get_host_key(Alg, Opts)
+ of
+ _PrivHostKey -> true
+ catch
+ _:_ -> false
end.
%%%----------------------------------------------------------------
diff --git a/lib/ssh/src/ssh_file.erl b/lib/ssh/src/ssh_file.erl
index 669b0f9be2..c5824b2519 100644
--- a/lib/ssh/src/ssh_file.erl
+++ b/lib/ssh/src/ssh_file.erl
@@ -268,7 +268,8 @@ identity_pass_phrase("rsa-sha2-384" ) -> rsa_pass_phrase;
identity_pass_phrase("rsa-sha2-512" ) -> rsa_pass_phrase;
identity_pass_phrase("ecdsa-sha2-"++_) -> ecdsa_pass_phrase;
identity_pass_phrase(P) when is_atom(P) ->
- identity_pass_phrase(atom_to_list(P)).
+ identity_pass_phrase(atom_to_list(P));
+identity_pass_phrase(_) -> undefined.
lookup_host_key_fd(Fd, KeyToMatch, Host, KeyType) ->
case io:get_line(Fd, '') of
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index f49b49b2df..cc3ef46fc2 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -52,6 +52,7 @@
ssh_packet/2, pack/2,
valid_key_sha_alg/2,
sha/1, sign/3, verify/5,
+ get_host_key/2,
call_KeyCb/3]).
-export([dbg_trace/3]).
@@ -432,7 +433,8 @@ key_exchange_first_msg(Kex, Ssh0) when Kex == 'ecdh-sha2-nistp256' ;
%%%
handle_kexdh_init(#ssh_msg_kexdh_init{e = E},
Ssh0 = #ssh{algorithms = #alg{kex=Kex,
- hkey=SignAlg} = Algs}) ->
+ hkey=SignAlg} = Algs,
+ opts = Opts}) ->
%% server
{G, P} = dh_group(Kex),
if
@@ -440,7 +442,7 @@ handle_kexdh_init(#ssh_msg_kexdh_init{e = E},
Sz = dh_bits(Algs),
{Public, Private} = generate_key(dh, [P,G,2*Sz]),
K = compute_key(dh, E, Private, [P,G]),
- MyPrivHostKey = get_host_key(Ssh0, SignAlg),
+ MyPrivHostKey = get_host_key(SignAlg, Opts),
MyPubHostKey = extract_public_key(MyPrivHostKey),
H = kex_hash(Ssh0, MyPubHostKey, sha(Kex), {E,Public,K}),
H_SIG = sign(H, sha(SignAlg), MyPrivHostKey),
@@ -579,14 +581,15 @@ handle_kex_dh_gex_init(#ssh_msg_kex_dh_gex_init{e = E},
#ssh{keyex_key = {{Private, Public}, {G, P}},
keyex_info = {Min, Max, NBits},
algorithms = #alg{kex=Kex,
- hkey=SignAlg}} = Ssh0) ->
+ hkey=SignAlg},
+ opts = Opts} = Ssh0) ->
%% server
if
1=<E, E=<(P-1) ->
K = compute_key(dh, E, Private, [P,G]),
if
1<K, K<(P-1) ->
- MyPrivHostKey = get_host_key(Ssh0, SignAlg),
+ MyPrivHostKey = get_host_key(SignAlg, Opts),
MyPubHostKey = extract_public_key(MyPrivHostKey),
H = kex_hash(Ssh0, MyPubHostKey, sha(Kex), {Min,NBits,Max,P,G,E,Public,K}),
H_SIG = sign(H, sha(SignAlg), MyPrivHostKey),
@@ -654,7 +657,8 @@ handle_kex_dh_gex_reply(#ssh_msg_kex_dh_gex_reply{public_host_key = PeerPubHostK
%%%
handle_kex_ecdh_init(#ssh_msg_kex_ecdh_init{q_c = PeerPublic},
Ssh0 = #ssh{algorithms = #alg{kex=Kex,
- hkey=SignAlg}}) ->
+ hkey=SignAlg},
+ opts = Opts}) ->
%% at server
Curve = ecdh_curve(Kex),
{MyPublic, MyPrivate} = generate_key(ecdh, Curve),
@@ -662,7 +666,7 @@ handle_kex_ecdh_init(#ssh_msg_kex_ecdh_init{q_c = PeerPublic},
compute_key(ecdh, PeerPublic, MyPrivate, Curve)
of
K ->
- MyPrivHostKey = get_host_key(Ssh0, SignAlg),
+ MyPrivHostKey = get_host_key(SignAlg, Opts),
MyPubHostKey = extract_public_key(MyPrivHostKey),
H = kex_hash(Ssh0, MyPubHostKey, sha(Curve), {PeerPublic, MyPublic, K}),
H_SIG = sign(H, sha(SignAlg), MyPrivHostKey),
@@ -778,7 +782,7 @@ sid(#ssh{session_id = Id}, _) -> Id.
%%
%% The host key should be read from storage
%%
-get_host_key(#ssh{opts=Opts}, SignAlg) ->
+get_host_key(SignAlg, Opts) ->
case call_KeyCb(host_key, [SignAlg], Opts) of
{ok, PrivHostKey} ->
%% Check the key - the KeyCb may be a buggy plugin