scd: Implement socket redirection.

* scd/scdaemon.c (ENAMETOOLONG): New.
(redir_socket_name): New.
(cleanup): Take care of a redirected socket.
(main): Pass redir_socket_name to create_server_socket.
(create_socket_name): Remove superfluous length check.
(create_server_socket): Add arg r_redir_name and implement
redirection.  Replace assert for older Assuan by an error message.

Signed-off-by: Werner Koch <[email protected]>

2 files changed, 69 insertions, 27 deletions

diff --git a/agent/gpg-agent.c b/agent/gpg-agent.c
index 7576cf93c..de40e3b4e 100644
--- a/agent/gpg-agent.c
+++ b/agent/gpg-agent.c
@@ -1525,8 +1525,8 @@ create_socket_name (char *standard_name, int with_homedir)
 /* Create a Unix domain socket with NAME.  Returns the file descriptor
    or terminates the process in case of an error.  Note that this
    function needs to be used for the regular socket first (indicated
-   by PRIMARY) and only then for the extra and the ssh sockets.  if
-   the soecket has been redirected the name of the real socket is
+   by PRIMARY) and only then for the extra and the ssh sockets.  If
+   the socket has been redirected the name of the real socket is
    stored as a malloced string at R_REDIR_NAME.  */
 static gnupg_fd_t
 create_server_socket (char *name, int primary,
diff --git a/scd/scdaemon.c b/scd/scdaemon.c
index 77b6283e9..763ce2d90 100644
--- a/scd/scdaemon.c
+++ b/scd/scdaemon.c
@@ -55,6 +55,9 @@
 #include "asshelp.h"
 #include "../common/init.h"
 
+#ifndef ENAMETOOLONG
+# define ENAMETOOLONG EINVAL
+#endif
 
 enum cmd_and_opt_values
 { aNull = 0,
@@ -194,6 +197,8 @@ static int pipe_server;
 
 /* Name of the communication socket */
 static char *socket_name;
+/* Name of the redirected socket or NULL.  */
+static char *redir_socket_name;
 
 /* We need to keep track of the server's nonces (these are dummies for
    POSIX systems). */
@@ -207,6 +212,7 @@ static int ticker_disabled;
 
 static char *create_socket_name (char *standard_name);
 static gnupg_fd_t create_server_socket (const char *name,
+                                        char **r_redir_name,
                                         assuan_sock_nonce_t *nonce);
 
 static void *start_connection_thread (void *arg);
@@ -357,14 +363,17 @@ cleanup (void)
 {
   if (socket_name && *socket_name)
     {
+      char *name;
       char *p;
 
-      remove (socket_name);
-      p = strrchr (socket_name, '/');
+      name = redir_socket_name? redir_socket_name : socket_name;
+
+      gnupg_remove (name);
+      p = strrchr (name, '/');
       if (p)
         {
           *p = 0;
-          rmdir (socket_name);
+          rmdir (name);
           *p = '/';
         }
       *socket_name = 0;
@@ -736,7 +745,8 @@ main (int argc, char **argv )
       if (multi_server)
         {
           socket_name = create_socket_name (SCDAEMON_SOCK_NAME);
-          fd = FD2INT(create_server_socket (socket_name, &socket_nonce));
+          fd = FD2INT(create_server_socket (socket_name,
+                                            &redir_socket_name, &socket_nonce));
         }
 
       res = npth_attr_init (&tattr);
@@ -788,7 +798,8 @@ main (int argc, char **argv )
 
       /* Create the socket.  */
       socket_name = create_socket_name (SCDAEMON_SOCK_NAME);
-      fd = FD2INT (create_server_socket (socket_name, &socket_nonce));
+      fd = FD2INT (create_server_socket (socket_name,
+                                         &redir_socket_name, &socket_nonce));
 
 
       fflush (NULL);
@@ -1025,26 +1036,28 @@ create_socket_name (char *standard_name)
       log_error (("'%s' are not allowed in the socket name\n"), PATHSEP_S);
       scd_exit (2);
     }
-  if (strlen (name) + 1 >= DIMof (struct sockaddr_un, sun_path) )
-    {
-      log_error (_("name of socket too long\n"));
-      scd_exit (2);
-    }
   return name;
 }
 
 
 
 /* Create a Unix domain socket with NAME.  Returns the file descriptor
-   or terminates the process in case of an error. */
+   or terminates the process in case of an error.  If the socket has
+   been redirected the name of the real socket is stored as a malloced
+   string at R_REDIR_NAME. */
 static gnupg_fd_t
-create_server_socket (const char *name, assuan_sock_nonce_t *nonce)
+create_server_socket (const char *name, char **r_redir_name,
+                      assuan_sock_nonce_t *nonce)
 {
-  struct sockaddr_un *serv_addr;
+  struct sockaddr *addr;
+  struct sockaddr_un *unaddr;
   socklen_t len;
   gnupg_fd_t fd;
   int rc;
 
+  xfree (*r_redir_name);
+  *r_redir_name = NULL;
+
   fd = assuan_sock_new (AF_UNIX, SOCK_STREAM, 0);
   if (fd == GNUPG_INVALID_FD)
     {
@@ -1052,26 +1065,55 @@ create_server_socket (const char *name, assuan_sock_nonce_t *nonce)
       scd_exit (2);
     }
 
-  serv_addr = xmalloc (sizeof (*serv_addr));
-  memset (serv_addr, 0, sizeof *serv_addr);
-  serv_addr->sun_family = AF_UNIX;
-  assert (strlen (name) + 1 < sizeof (serv_addr->sun_path));
-  strcpy (serv_addr->sun_path, name);
-  len = SUN_LEN (serv_addr);
+  unaddr = xmalloc (sizeof (*unaddr));
+  addr = (struct sockaddr*)unaddr;
+
+#if ASSUAN_VERSION_NUMBER >= 0x020104 /* >= 2.1.4 */
+  {
+    int redirected;
+
+    if (assuan_sock_set_sockaddr_un (name, addr, &redirected))
+      {
+        if (errno == ENAMETOOLONG)
+          log_error (_("socket name '%s' is too long\n"), name);
+        else
+          log_error ("error preparing socket '%s': %s\n",
+                     name, gpg_strerror (gpg_error_from_syserror ()));
+        scd_exit (2);
+      }
+    if (redirected)
+      {
+        *r_redir_name = xstrdup (unaddr->sun_path);
+        if (opt.verbose)
+          log_info ("redirecting socket '%s' to '%s'\n", name, *r_redir_name);
+      }
+  }
+#else /* Assuan < 2.1.4 */
+  memset (unaddr, 0, sizeof *unaddr);
+  unaddr->sun_family = AF_UNIX;
+  if (strlen (name) + 1 >= sizeof (unaddr->sun_path))
+    {
+      log_error (_("socket name '%s' is too long\n"), name);
+      scd_exit (2);
+    }
+  strcpy (unaddr->sun_path, name);
+#endif /* Assuan < 2.1.4 */
+
+  len = SUN_LEN (unaddr);
 
-  rc = assuan_sock_bind (fd, (struct sockaddr*) serv_addr, len);
+  rc = assuan_sock_bind (fd, addr, len);
   if (rc == -1 && errno == EADDRINUSE)
     {
-      remove (name);
-      rc = assuan_sock_bind (fd, (struct sockaddr*) serv_addr, len);
+      gnupg_remove (unaddr->sun_path);
+      rc = assuan_sock_bind (fd, addr, len);
     }
   if (rc != -1
-      && (rc=assuan_sock_get_nonce ((struct sockaddr*)serv_addr, len, nonce)))
+      && (rc=assuan_sock_get_nonce (addr, len, nonce)))
     log_error (_("error getting nonce for the socket\n"));
  if (rc == -1)
     {
       log_error (_("error binding socket to '%s': %s\n"),
-		 serv_addr->sun_path,
+		 unaddr->sun_path,
                  gpg_strerror (gpg_error_from_syserror ()));
       assuan_sock_close (fd);
       scd_exit (2);
@@ -1086,7 +1128,7 @@ create_server_socket (const char *name, assuan_sock_nonce_t *nonce)
     }
 
   if (opt.verbose)
-    log_info (_("listening on socket '%s'\n"), serv_addr->sun_path);
+    log_info (_("listening on socket '%s'\n"), unaddr->sun_path);
 
   return fd;
 }