[2.7] bpo-32185: Don't send IP in SNI TLS extension (GH-5865) (#5871)
The SSL module no longer sends IP addresses in SNI TLS extension on
platforms with OpenSSL 1.0.2+ or inet_pton.
Signed-off-by: Christian Heimes <christian@python.org>
(cherry picked from commit e9370a47389903bb72badc95032ec84a0ebbf8cc)
Co-authored-by: Christian Heimes <christian@python.org>
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index ec61a70..f09f9c9 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -52,6 +52,11 @@
#include <sys/poll.h>
#endif
+#ifndef MS_WINDOWS
+/* inet_pton */
+#include <arpa/inet.h>
+#endif
+
/* Don't warn about deprecated functions */
#ifdef __GNUC__
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
@@ -575,8 +580,41 @@
SSL_set_mode(self->ssl, mode);
#if HAVE_SNI
- if (server_hostname != NULL)
- SSL_set_tlsext_host_name(self->ssl, server_hostname);
+ if (server_hostname != NULL) {
+/* Don't send SNI for IP addresses. We cannot simply use inet_aton() and
+ * inet_pton() here. inet_aton() may be linked weakly and inet_pton() isn't
+ * available on all platforms. Use OpenSSL's IP address parser. It's
+ * available since 1.0.2 and LibreSSL since at least 2.3.0. */
+ int send_sni = 1;
+#if OPENSSL_VERSION_NUMBER >= 0x10200000L
+ ASN1_OCTET_STRING *ip = a2i_IPADDRESS(server_hostname);
+ if (ip == NULL) {
+ send_sni = 1;
+ ERR_clear_error();
+ } else {
+ send_sni = 0;
+ ASN1_OCTET_STRING_free(ip);
+ }
+#elif defined(HAVE_INET_PTON)
+#ifdef ENABLE_IPV6
+ char packed[Py_MAX(sizeof(struct in_addr), sizeof(struct in6_addr))];
+#else
+ char packed[sizeof(struct in_addr)];
+#endif /* ENABLE_IPV6 */
+ if (inet_pton(AF_INET, server_hostname, packed)) {
+ send_sni = 0;
+#ifdef ENABLE_IPV6
+ } else if(inet_pton(AF_INET6, server_hostname, packed)) {
+ send_sni = 0;
+#endif /* ENABLE_IPV6 */
+ } else {
+ send_sni = 1;
+ }
+#endif /* HAVE_INET_PTON */
+ if (send_sni) {
+ SSL_set_tlsext_host_name(self->ssl, server_hostname);
+ }
+ }
#endif
/* If the socket is in non-blocking mode or timeout mode, set the BIO