Don't prefer ECDHE-ECDSA ciphers when the client appears to be Safari on OS X.
OS X 10.8..10.8.3 has broken support for ECDHE-ECDSA ciphers.
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 151e7b8..66119d4 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -1899,6 +1899,89 @@
return -1;
}
+#ifndef OPENSSL_NO_EC
+/* ssl_check_for_safari attempts to fingerprint Safari using OS X
+ * SecureTransport using the TLS extension block in |d|, of length |n|.
+ * Safari, since 10.6, sends exactly these extensions, in this order:
+ * SNI,
+ * elliptic_curves
+ * ec_point_formats
+ *
+ * We wish to fingerprint Safari because they broke ECDHE-ECDSA support in 10.8,
+ * but they advertise support. So enabling ECDHE-ECDSA ciphers breaks them.
+ * Sadly we cannot differentiate 10.6, 10.7 and 10.8.4 (which work), from
+ * 10.8..10.8.3 (which don't work).
+ */
+static void ssl_check_for_safari(SSL *s, const unsigned char *data, const unsigned char *d, int n) {
+ unsigned short type, size;
+ static const unsigned char kSafariExtensionsBlock[] = {
+ 0x00, 0x0a, /* elliptic_curves extension */
+ 0x00, 0x08, /* 8 bytes */
+ 0x00, 0x06, /* 6 bytes of curve ids */
+ 0x00, 0x17, /* P-256 */
+ 0x00, 0x18, /* P-384 */
+ 0x00, 0x19, /* P-521 */
+
+ 0x00, 0x0b, /* ec_point_formats */
+ 0x00, 0x02, /* 2 bytes */
+ 0x01, /* 1 point format */
+ 0x00, /* uncompressed */
+ };
+
+ /* The following is only present in TLS 1.2 */
+ static const unsigned char kSafariTLS12ExtensionsBlock[] = {
+ 0x00, 0x0d, /* signature_algorithms */
+ 0x00, 0x0c, /* 12 bytes */
+ 0x00, 0x0a, /* 10 bytes */
+ 0x05, 0x01, /* SHA-384/RSA */
+ 0x04, 0x01, /* SHA-256/RSA */
+ 0x02, 0x01, /* SHA-1/RSA */
+ 0x04, 0x03, /* SHA-256/ECDSA */
+ 0x02, 0x03, /* SHA-1/ECDSA */
+ };
+
+ if (data >= (d+n-2))
+ return;
+ data += 2;
+
+ if (data > (d+n-4))
+ return;
+ n2s(data,type);
+ n2s(data,size);
+
+ if (type != TLSEXT_TYPE_server_name)
+ return;
+
+ if (data+size > d+n)
+ return;
+ data += size;
+
+ if (TLS1_get_version(s) >= TLS1_2_VERSION)
+ {
+ const size_t len1 = sizeof(kSafariExtensionsBlock);
+ const size_t len2 = sizeof(kSafariTLS12ExtensionsBlock);
+
+ if (data + len1 + len2 != d+n)
+ return;
+ if (memcmp(data, kSafariExtensionsBlock, len1) != 0)
+ return;
+ if (memcmp(data + len1, kSafariTLS12ExtensionsBlock, len2) != 0)
+ return;
+ }
+ else
+ {
+ const size_t len = sizeof(kSafariExtensionsBlock);
+
+ if (data + len != d+n)
+ return;
+ if (memcmp(data, kSafariExtensionsBlock, len) != 0)
+ return;
+ }
+
+ s->s3->is_probably_safari = 1;
+}
+#endif /* OPENSSL_NO_EC */
+
static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d, int n, int *al)
{
unsigned short type;
@@ -1932,6 +2015,12 @@
s->tlsext_heartbeat &= ~(SSL_TLSEXT_HB_ENABLED |
SSL_TLSEXT_HB_DONT_SEND_REQUESTS);
#endif
+
+#ifndef OPENSSL_NO_EC
+ if (s->options & SSL_OP_SAFARI_ECDHE_ECDSA_BUG)
+ ssl_check_for_safari(s, data, d, n);
+#endif /* OPENSSL_NO_EC */
+
/* Clear any signature algorithms extension received */
if (s->cert->peer_sigalgs)
{
