[PATCH v4 7/8] server: Introduce error when attempting to connect() to abstract AF_UNIX sockets.

[Ally Sommers]

From: Ally Sommers

---
 server/sock.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/server/sock.c b/server/sock.c
index 37181bd668e..aa88e041216 100644
--- a/server/sock.c
+++ b/server/sock.c
@@ -2639,17 +2639,28 @@ static void sock_ioctl( struct fd *fd, ioctl_code_t code, struct async *async )
         if (unix_addr.addr.sa_family == AF_INET && !memcmp( &unix_addr.in.sin_addr, magic_loopback_addr, 4 ))
             unix_addr.in.sin_addr.s_addr = htonl( INADDR_LOOPBACK );

-        if (sock->family == WS_AF_UNIX && *((char *)(params + 1) + params->addr_len))
+        if (sock->family == WS_AF_UNIX)
         {
-            char *unix_path = (char *)(params + 1) + params->addr_len;
-            char unix_path_copy[PATH_MAX];
-            strcpy(unix_path_copy, unix_path);
-            if (chdir( dirname( unix_path_copy ) ) == -1)
+            if (*(char *)(params + 1))
             {
-                set_error( sock_get_ntstatus( errno ) );
+                char *unix_path = (char *)(params + 1) + params->addr_len;
+                char unix_path_copy[PATH_MAX];
+                strcpy(unix_path_copy, unix_path);
+                if (chdir( dirname( unix_path_copy ) ) == -1)
+                {
+                    set_error( sock_get_ntstatus( errno ) );
+                    return;
+                }
+                memcpy( unix_addr.un.sun_path, basename( unix_path ), sizeof(unix_addr.un.sun_path) );
+            }
+            else
+            {
+                /* Contrary to documentation, Windows does not currently support abstract Unix
+                 * sockets. connect() throws WSAEINVAL if sun_family is AF_UNIX and sun_path
+                 * begins with '\0', even though bind() will succeed. */
+                set_win32_error( WSAEINVAL );
                 return;
             }
-            memcpy( unix_addr.un.sun_path, basename( unix_path ), sizeof(unix_addr.un.sun_path) );
         }

ret = connect( unix_fd, &unix_addr.addr, unix_len );