ext/openssl: always use our implementation of SSL_SESSION_cmp()

Implement CRYPTO_memcmp() if it is not available.
Always use our SSL_SESSION_cmp() (renamed to ossl_SSL_SESSION_cmp()).

SSL_SESSION_cmp() was removed in OpenSSL 1.0.0 and we have used a
reimplemented one. However our implementation is better than the
original (it uses CRYPTO_memcmp() instead of plain memcmp).

1 files changed, 18 insertions, 0 deletions

diff --git a/ext/openssl/openssl_missing.c b/ext/openssl/openssl_missing.c
index bd8eef5ea9..f9db04fe97 100644
--- a/ext/openssl/openssl_missing.c
+++ b/ext/openssl/openssl_missing.c
@@ -352,3 +352,21 @@ ASN1_put_eoc(unsigned char **pp)
     return 2;
 }
 #endif
+
+#if !defined(HAVE_CRYPTO_MEMCMP)
+int
+CRYPTO_memcmp(const volatile void * volatile in_a,
+	      const volatile void * volatile in_b,
+	      size_t len)
+{
+    size_t i;
+    const volatile unsigned char *a = in_a;
+    const volatile unsigned char *b = in_b;
+    unsigned char x = 0;
+
+    for (i = 0; i < len; i++)
+	x |= a[i] ^ b[i];
+
+    return x;
+}
+#endif