Applying 1st patch from Andrew Cann (see also #2887).

https://canndrew.org/misc/trim_abstract_socket_paths.diff [^]

This changes the addrlen argument passed to the connect, bind and sendto
syscalls to reflect the length of the string in sockaddr_un.sun_path. I
was trying to talk to GNUnet services using socat and discovered that it
expects abstract sockets to be created this way and won't connect
otherwise. Looking at some other programs that I could talk to using
socat (dbus, X11), this is how they create abstract sockets as well.

1 files changed, 39 insertions, 1 deletions

diff --git a/src/util/network.c b/src/util/network.c
index 0dbc0b094..c0b977368 100644
--- a/src/util/network.c
+++ b/src/util/network.c
@@ -393,6 +393,20 @@ GNUNET_NETWORK_socket_bind (struct GNUNET_NETWORK_Handle *desc,
                             int flags)
 {
   int ret;
+  socklen_t bind_address_len = address_len;
+
+#ifdef LINUX
+  if (address->sa_family == AF_UNIX)
+  {
+    const struct sockaddr_un *address_un = (const struct sockaddr_un *)address;
+    if (address_un->sun_path[0] == '\0')
+      bind_address_len = \
+          sizeof (struct sockaddr_un) \
+        - sizeof (address_un->sun_path) \
+        + strnlen (address_un->sun_path + 1, sizeof (address_un->sun_path) - 1) \
+        + 1;
+  }
+#endif
 
 #ifdef IPV6_V6ONLY
 #ifdef IPPROTO_IPV6
@@ -427,7 +441,7 @@ GNUNET_NETWORK_socket_bind (struct GNUNET_NETWORK_Handle *desc,
   }
 #endif
 #endif
-  ret = bind (desc->fd, address, address_len);
+  ret = bind (desc->fd, address, bind_address_len);
 #ifdef MINGW
   if (SOCKET_ERROR == ret)
     SetErrnoFromWinsockError (WSAGetLastError ());
@@ -544,6 +558,18 @@ GNUNET_NETWORK_socket_connect (const struct GNUNET_NETWORK_Handle *desc,
 {
   int ret;
 
+#ifdef LINUX
+  if (address->sa_family == AF_UNIX)
+  {
+    const struct sockaddr_un *address_un = (const struct sockaddr_un *)address;
+    if(address_un->sun_path[0] == '\0')
+      address_len = \
+          sizeof (struct sockaddr_un) \
+        - sizeof (address_un->sun_path) \
+        + strnlen (address_un->sun_path + 1, sizeof (address_un->sun_path) - 1) \
+        + 1;
+  }
+#endif
   ret = connect (desc->fd, address, address_len);
 
 #ifdef MINGW
@@ -768,6 +794,18 @@ GNUNET_NETWORK_socket_sendto (const struct GNUNET_NETWORK_Handle * desc,
 #ifdef MSG_NOSIGNAL
   flags |= MSG_NOSIGNAL;
 #endif
+#ifdef LINUX
+  if (dest_addr->sa_family == AF_UNIX)
+  {
+    const struct sockaddr_un *dest_addr_un = (const struct sockaddr_un *)dest_addr;
+    if (dest_addr_un->sun_path[0] == '\0')
+      dest_len = \
+          sizeof (struct sockaddr) \
+        - sizeof (dest_addr_un->sun_path) \
+        + strnlen (dest_addr_un->sun_path + 1, sizeof (dest_addr_un->sun_path) - 1) \
+        + 1;
+  }
+#endif
   ret = sendto (desc->fd, message, length, flags, dest_addr, dest_len);
 #ifdef MINGW
   if (SOCKET_ERROR == ret)