diff options
| -rw-r--r-- | lib/ssh/src/ssh_transport.erl | 28 |
1 files changed, 23 insertions, 5 deletions
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl index d1a3d513d1..afc3733563 100644 --- a/lib/ssh/src/ssh_transport.erl +++ b/lib/ssh/src/ssh_transport.erl @@ -1097,9 +1097,21 @@ alg_final(rcv, SSH0) -> select_all(CL, SL) when length(CL) + length(SL) < ?MAX_NUM_ALGORITHMS -> - A = CL -- SL, %% algortihms only used by client + %% algortihms only used by client + %% NOTE: an algorithm occuring more than once in CL will still be present + %% in CLonly. This is not a problem for nice clients. + CLonly = CL -- SL, + %% algorithms used by client and server (client pref) - lists:map(fun(ALG) -> list_to_atom(ALG) end, (CL -- A)); + lists:foldr(fun(ALG, Acc) -> + try [list_to_existing_atom(ALG) | Acc] + catch + %% If an malicious client uses the same non-existing algorithm twice, + %% we will end up here + _:_ -> Acc + end + end, [], (CL -- CLonly)); + select_all(CL, SL) -> Error = lists:concat(["Received too many algorithms (",length(CL),"+",length(SL)," >= ",?MAX_NUM_ALGORITHMS,")."]), ?DISCONNECT(?SSH_DISCONNECT_PROTOCOL_ERROR, @@ -1800,7 +1812,10 @@ valid_key_sha_alg(_, _) -> false. valid_key_sha_alg_ec(OID, Alg) -> Curve = public_key:oid2ssh_curvename(OID), - Alg == list_to_atom("ecdsa-sha2-" ++ binary_to_list(Curve)). + try Alg == list_to_existing_atom("ecdsa-sha2-" ++ binary_to_list(Curve)) + catch + _:_ -> false + end. -dialyzer({no_match, public_algo/1}). @@ -1811,7 +1826,10 @@ public_algo({ed_pub, ed25519,_}) -> 'ssh-ed25519'; public_algo({ed_pub, ed448,_}) -> 'ssh-ed448'; public_algo({#'ECPoint'{},{namedCurve,OID}}) -> Curve = public_key:oid2ssh_curvename(OID), - list_to_atom("ecdsa-sha2-" ++ binary_to_list(Curve)). + try list_to_existing_atom("ecdsa-sha2-" ++ binary_to_list(Curve)) + catch + _:_ -> undefined + end. sha('ssh-rsa') -> sha; @@ -1845,7 +1863,7 @@ sha('curve25519-sha256@libssh.org' ) -> sha256; sha('curve448-sha512') -> sha512; sha(x25519) -> sha256; sha(x448) -> sha512; -sha(Str) when is_list(Str), length(Str)<50 -> sha(list_to_atom(Str)). +sha(Str) when is_list(Str), length(Str)<50 -> sha(list_to_existing_atom(Str)). mac_key_bytes('hmac-sha1') -> 20; |