Allow public_key:pem_entry_decode/2) to handle AES-128-CBC ciphered keys

Private keys generated by modern versions of ssh-keygen are ciphered
with AES-128-CBC instead of DES-EDE3-CBC.


Since DES-EDE3-CBC ciphered keys are handled, and the underlying
support for AES-128-CBC is already present, it seems a bug of omission
that AES-128-CBC ciphered keys are not.

4 files changed, 55 insertions, 2 deletions

diff --git a/lib/public_key/src/pubkey_pbe.erl b/lib/public_key/src/pubkey_pbe.erl
index 6f0be53db9..460624163b 100644
--- a/lib/public_key/src/pubkey_pbe.erl
+++ b/lib/public_key/src/pubkey_pbe.erl
@@ -66,7 +66,13 @@ decode(Data, Password,"DES-EDE3-CBC" = Cipher, KeyDevParams) ->
 
 decode(Data, Password,"RC2-CBC"= Cipher, KeyDevParams) ->
     {Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams),
-    crypto:block_decrypt(rc2_cbc, Key, IV, Data).
+    crypto:block_decrypt(rc2_cbc, Key, IV, Data);
+
+decode(Data, Password,"AES-128-CBC"= Cipher, IV) ->
+    %% PKCS5_SALT_LEN is 8 bytes
+    <<Salt:8/binary,_/binary>> = IV,
+    {Key, _} = password_to_key_and_iv(Password, Cipher, Salt),
+    crypto:block_decrypt(aes_cbc128, Key, IV, Data).
 
 %%--------------------------------------------------------------------
 -spec pbdkdf1(string(), iodata(), integer(), atom()) -> binary().
@@ -200,7 +206,9 @@ derived_key_length(Cipher,_) when (Cipher == ?'rc2CBC') or
     16;
 derived_key_length(Cipher,_) when (Cipher == ?'des-EDE3-CBC') or 
 				  (Cipher == "DES-EDE3-CBC") ->
-    24.
+    24;
+derived_key_length(Cipher,_) when (Cipher == "AES-128-CBC") ->
+    16.
 
 cipher(#'PBES2-params_encryptionScheme'{algorithm = ?'desCBC'}) ->
     "DES-CBC";
diff --git a/lib/public_key/src/public_key.erl b/lib/public_key/src/public_key.erl
index cdbfe6e07c..a4b6b8ad15 100644
--- a/lib/public_key/src/public_key.erl
+++ b/lib/public_key/src/public_key.erl
@@ -118,6 +118,13 @@ pem_entry_decode({Asn1Type, CryptDer, {Cipher, Salt}} = PemEntry,
 				is_list(Cipher) andalso
 				is_binary(Salt) andalso
 				erlang:byte_size(Salt) == 8 ->
+    do_pem_entry_decode(PemEntry, Password);
+pem_entry_decode({Asn1Type, CryptDer, {"AES-128-CBC"=Cipher, IV}} = PemEntry,
+		 Password) when is_atom(Asn1Type) andalso
+				is_binary(CryptDer) andalso
+				is_list(Cipher) andalso
+				is_binary(IV) andalso
+				erlang:byte_size(IV) == 16 ->
     do_pem_entry_decode(PemEntry, Password).
 
 %%--------------------------------------------------------------------
diff --git a/lib/public_key/test/pbe_SUITE.erl b/lib/public_key/test/pbe_SUITE.erl
index 2c9b17478d..b68ffbd5fd 100644
--- a/lib/public_key/test/pbe_SUITE.erl
+++ b/lib/public_key/test/pbe_SUITE.erl
@@ -218,6 +218,14 @@ encrypted_private_key_info(Config) when is_list(Config) ->
     [{'PrivateKeyInfo', _, {"RC2-CBC",_}} = PubEntry2] = PemRc2Entry,
     KeyInfo = public_key:pem_entry_decode(PubEntry2, "password"),
 
+    %% key generated with ssh-keygen -N hello_aes -f aes_128_cbc_enc_key
+    {ok, PemAesCbc} = file:read_file(filename:join(Datadir, "aes_128_cbc_enc_key")),
+
+    PemAesCbcEntry = public_key:pem_decode(PemAesCbc),
+    ct:print("Pem entry: ~p" , [PemAesCbcEntry]),
+    [{'RSAPrivateKey', _, {"AES-128-CBC",_}} = PubAesCbcEntry] = PemAesCbcEntry,
+    #'RSAPrivateKey'{} = public_key:pem_entry_decode(PubAesCbcEntry, "hello_aes"),
+
     check_key_info(KeyInfo).
 
 
diff --git a/lib/public_key/test/pbe_SUITE_data/aes_128_cbc_enc_key b/lib/public_key/test/pbe_SUITE_data/aes_128_cbc_enc_key
new file mode 100644
index 0000000000..34c7543f30
--- /dev/null
+++ b/lib/public_key/test/pbe_SUITE_data/aes_128_cbc_enc_key
@@ -0,0 +1,30 @@
+-----BEGIN RSA PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: AES-128-CBC,D64FF97327558643763BE17BD50FDDAD
+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-----END RSA PRIVATE KEY-----