Even though DES is super outdated and also NTLM is super outdated,
eliminating the warnings for OpenSSL 3.0 is still a step in the right
direction and using the correct APIs. We cheat a bit by using 3DES instead
of DES to avoid needing legacy provider for DES encryption for now.
Patch v4: add unit test, use 3DES to avoid legacy provider for now
Signed-off-by: Arne Schwabe <a...@rfc2549.org>
---
src/openvpn/crypto_openssl.c | 40 ++++++++++++++++++++++++--
tests/unit_tests/openvpn/test_crypto.c | 27 ++++++++++++++++-
2 files changed, 63 insertions(+), 4 deletions(-)
diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c
index 6b18551ea..999805e88 100644
--- a/src/openvpn/crypto_openssl.c
+++ b/src/openvpn/crypto_openssl.c
@@ -867,10 +867,44 @@ cipher_des_encrypt_ecb(const unsigned char
key[DES_KEY_LENGTH],
unsigned char src[DES_KEY_LENGTH],
unsigned char dst[DES_KEY_LENGTH])
{
- DES_key_schedule sched;
+ /* We are using 3DES here with three times the same key to cheat
+ * and emulate DES as 3DES is better supported than DES */
+ EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
+ if (!ctx)
+ {
+ crypto_msg(M_FATAL, "%s: EVP_CIPHER_CTX_new() failed", __func__);
+ }
+
+ unsigned char key3[DES_KEY_LENGTH*3];
+ for (int i = 0;i < 3;i++)
+ {
+ memcpy(key3 + (i * DES_KEY_LENGTH), key, DES_KEY_LENGTH);
+ }
- DES_set_key_unchecked((DES_cblock *)key, &sched);
- DES_ecb_encrypt((DES_cblock *)src, (DES_cblock *)dst, &sched, DES_ENCRYPT);
+ if (!EVP_EncryptInit_ex(ctx, EVP_des_ede3_ecb(), NULL, key3, 0))
+ {
+ crypto_msg(M_FATAL, "%s: EVP_EncryptInit_ex() failed", __func__);
+ }
+
+ int len;
+
+ /* The EVP_EncryptFinal method will write to the dst+len pointer even
+ * though there is nothing to encrypt anymore, provide space for that to
+ * not overflow the stack */
+ unsigned char dst2[DES_KEY_LENGTH * 2];
+ if(!EVP_EncryptUpdate(ctx, dst2, &len, src, DES_KEY_LENGTH))
+ {
+ crypto_msg(M_FATAL, "%s: EVP_EncryptUpdate() failed", __func__);
+ }
+
+ if (!EVP_EncryptFinal(ctx, dst2 + len, &len))
+ {
+ crypto_msg(M_FATAL, "%s: EVP_EncryptFinal() failed", __func__);
+ }
+
+ memcpy(dst, dst2, DES_KEY_LENGTH);
+
+ EVP_CIPHER_CTX_free(ctx);
}
/*
diff --git a/tests/unit_tests/openvpn/test_crypto.c
b/tests/unit_tests/openvpn/test_crypto.c
index 66f53a020..6d8d40896 100644
--- a/tests/unit_tests/openvpn/test_crypto.c
+++ b/tests/unit_tests/openvpn/test_crypto.c
@@ -212,6 +212,30 @@ crypto_test_hmac(void **state)
hmac_ctx_free(hmac);
}
+void
+test_des_encrypt(void **state)
+{
+ /* We have a small des encrypt method that is only for NTLMv1. This unit
+ * test ensures that it is not accidentally broken */
+
+ const unsigned char des_key[DES_KEY_LENGTH] = {0x42, 0x23};
+
+ const char *src = "MoinWelt";
+
+ /* cipher_des_encrypt_ecb wants a non const */
+ unsigned char *src2 = (unsigned char *) strdup(src);
+
+ unsigned char dst[DES_KEY_LENGTH];
+ cipher_des_encrypt_ecb(des_key, src2, dst);
+
+ const unsigned char dst_good[DES_KEY_LENGTH] = {0xd3, 0x8f, 0x61, 0xf7,
0xbe, 0x27, 0xb6, 0xa2};
+
+ assert_memory_equal(dst, dst_good, DES_KEY_LENGTH);
+
+ free(src2);
+}
+
+
int
main(void)
{
@@ -219,7 +243,8 @@ main(void)
cmocka_unit_test(crypto_pem_encode_decode_loopback),
cmocka_unit_test(crypto_translate_cipher_names),
cmocka_unit_test(crypto_test_tls_prf),
- cmocka_unit_test(crypto_test_hmac)
+ cmocka_unit_test(crypto_test_hmac),
+ cmocka_unit_test(test_des_encrypt)
};
#if defined(ENABLE_CRYPTO_OPENSSL)
--
2.33.0
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