From df422190db1062c4f286178f46241b11f6bb60ce Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <antoine@python.org>
Date: Mon, 1 May 2017 23:38:57 +0200
Subject: [PATCH 1/2] bpo-30205: Fix getsockname() for unbound AF_UNIX sockets
 on Linux

---
 Lib/test/test_socket.py | 4 ++++
 Modules/socketmodule.c  | 6 +++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index 2155d630dd4790..5e37fc608f26ad 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -4682,6 +4682,10 @@ def bind(self, sock, path):
             else:
                 raise
 
+    def testUnbound(self):
+        # Issue #30205
+        self.assertEqual(self.sock.getsockname(), '')
+
     def testStrAddr(self):
         # Test binding to and retrieving a normal string pathname.
         path = os.path.abspath(support.TESTFN)
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 6d5c256ff340d6..456c66478e9691 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -1211,9 +1211,9 @@ makesockaddr(SOCKET_T sockfd, struct sockaddr *addr, size_t addrlen, int proto)
     {
         struct sockaddr_un *a = (struct sockaddr_un *) addr;
 #ifdef __linux__
-        if (a->sun_path[0] == 0) {  /* Linux abstract namespace */
-            addrlen -= offsetof(struct sockaddr_un, sun_path);
-            return PyBytes_FromStringAndSize(a->sun_path, addrlen);
+        size_t linuxaddrlen = addrlen - offsetof(struct sockaddr_un, sun_path);
+        if (linuxaddrlen > 0 && a->sun_path[0] == 0) {  /* Linux abstract namespace */
+            return PyBytes_FromStringAndSize(a->sun_path, linuxaddrlen);
         }
         else
 #endif /* linux */

From b43be2c28b2d1abdb2817e0c4d3a2b3498692b9d Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <antoine@python.org>
Date: Tue, 2 May 2017 17:01:29 +0200
Subject: [PATCH 2/2] Add NEWS entry

---
 Misc/NEWS | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Misc/NEWS b/Misc/NEWS
index 118483f9437ed4..c3eaaf2d4df664 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -317,6 +317,8 @@ Extension Modules
 Library
 -------
 
+- bpo-30205: Fix getsockname() for unbound AF_UNIX sockets on Linux.
+
 - bpo-30228: The seek() and tell() methods of io.FileIO now set the internal
   seekable attribute to avoid one syscall on open() (in buffered or text mode).