[Openvpn-devel] [XS] Change in openvpn[release/2.6]: Do not try to use the encrypt-then-mac ciphers from OpenSSL 3.6.0

[plaisthos (C. Review) <ge...@op...>]

Attention is currently required from: flichtenheld.

Hello flichtenheld,

I'd like you to do a code review.
Please visit

    http://gerrit.openvpn.net/c/openvpn/+/1295?usp=email

to review the following change.


Change subject: Do not try to use the encrypt-then-mac ciphers from OpenSSL 3.6.0
......................................................................

Do not try to use the encrypt-then-mac ciphers from OpenSSL 3.6.0

These ciphers claim to be CBC but since they are also include an HMAC
are more a mix of AEAD and CBC. Nevertheless, we do not support these
and also have no (good) reason to support them.

Change-Id: Iafe3c94b952cd3fbecf6f3d05816e5859f425e7d
Signed-off-by: Arne Schwabe <ar...@rf...>
---
M src/openvpn/crypto_openssl.c
M src/openvpn/openssl_compat.h
2 files changed, 7 insertions(+), 1 deletion(-)



  git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/95/1295/1

diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c
index 331af99..280389c 100644
--- a/src/openvpn/crypto_openssl.c
+++ b/src/openvpn/crypto_openssl.c
@@ -798,7 +798,8 @@
 #ifdef EVP_CIPH_FLAG_CTS
                           && !(EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_CTS)
 #endif
-                          && !(EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER));
+                          && !(EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)
+                          && !(EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_ENC_THEN_MAC));
     EVP_CIPHER_free(cipher);
     return ret;
 }
diff --git a/src/openvpn/openssl_compat.h b/src/openvpn/openssl_compat.h
index c9fa719..03ece13 100644
--- a/src/openvpn/openssl_compat.h
+++ b/src/openvpn/openssl_compat.h
@@ -817,4 +817,9 @@
 
 #endif /* OPENSSL_VERSION_NUMBER < 0x30000000L */
 
+/* Introduced in OpenSSL 3.6.0 */
+#ifndef EVP_CIPH_FLAG_ENC_THEN_MAC
+#define EVP_CIPH_FLAG_ENC_THEN_MAC 0x10000000
+#endif
+
 #endif /* OPENSSL_COMPAT_H_ */

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Gerrit-MessageType: newchange
Gerrit-Project: openvpn
Gerrit-Branch: release/2.6
Gerrit-Change-Id: Iafe3c94b952cd3fbecf6f3d05816e5859f425e7d
Gerrit-Change-Number: 1295
Gerrit-PatchSet: 1
Gerrit-Owner: plaisthos <arn...@rf...>
Gerrit-Reviewer: flichtenheld <fr...@li...>
Gerrit-CC: openvpn-devel <ope...@li...>
Gerrit-Attention: flichtenheld <fr...@li...>