backport: add a a constant for pyOpenSSL with OpenSSL 3

src/_cffi_src/openssl/err.py

@@ -29,6 +29,10 @@
 static const int SSL_TLSEXT_ERR_NOACK;
 
 static const int X509_R_CERT_ALREADY_IN_HASH_TABLE;
+
+static const int SSL_R_UNEXPECTED_EOF_WHILE_READING;
+
+static const int Cryptography_HAS_UNEXPECTED_EOF_WHILE_READING;
 """
 
 FUNCTIONS = """
@@ -67,4 +71,13 @@
 #else
 static const int CIPHER_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH = 0;
 #endif
+
+/* SSL_R_UNEXPECTED_EOF_WHILE_READING is needed for pyOpenSSL
+   with OpenSSL 3+ */
+#if defined(SSL_R_UNEXPECTED_EOF_WHILE_READING)
+#define Cryptography_HAS_UNEXPECTED_EOF_WHILE_READING 1
+#else
+#define Cryptography_HAS_UNEXPECTED_EOF_WHILE_READING 0
+#define SSL_R_UNEXPECTED_EOF_WHILE_READING 0
+#endif
 """

src/cryptography/hazmat/bindings/openssl/_conditional.py

@@ -301,6 +301,10 @@ def cryptography_has_300_evp_cipher() -> typing.List[str]:
     return ["EVP_CIPHER_fetch", "EVP_CIPHER_free"]
 
 
+def cryptography_has_unexpected_eof_while_reading() -> typing.List[str]:
+    return ["SSL_R_UNEXPECTED_EOF_WHILE_READING"]
+
+
 # This is a mapping of
 # {condition: function-returning-names-dependent-on-that-condition} so we can
 # loop over them and delete unsupported names at runtime. It will be removed
@@ -357,4 +361,7 @@ def cryptography_has_300_evp_cipher() -> typing.List[str]:
     "Cryptography_HAS_BN_FLAGS": cryptography_has_bn_flags,
     "Cryptography_HAS_EVP_PKEY_DH": cryptography_has_evp_pkey_dh,
     "Cryptography_HAS_300_EVP_CIPHER": cryptography_has_300_evp_cipher,
+    "Cryptography_HAS_UNEXPECTED_EOF_WHILE_READING": (
+        cryptography_has_unexpected_eof_while_reading
+    ),
 }