[PATCH] scd: PC/SC reader selection by partial string match.

[NIIBE Yutaka]

Hello,

I'm going to push following patch to GnuPG 2.1.x.  This fix is
related to the issue 1618 and 1930.

    https://bugs.gnupg.org/gnupg/issue1618
    https://bugs.gnupg.org/gnupg/issue1930

For 1930, I put a patch for 2.0.x in the bug tracker, but I haven't
got response from the reporter.  As I tested with GnuPG 2.1.x, this
patch is now for 2.1.x.  I plan to backport to 2.0 (use the one in
issue1930), soon.

The card reader name by PC/SC service might include USB bus, which
varies (on some platform like GNU/Linux).  Thus, it's better to match
partial string.

Original patch was submitted by anstein in 1930.  I changed it to
fallback to the first reader if no match found.

Note that we need to change pcsc-wrapper.c in 2.0 backport.

It works for me with pcscd and libccid on GNU/Linux.  The readers
are VASCO DIGIKEY 920 and Gnuk Token.


diff --git a/scd/apdu.c b/scd/apdu.c
index f6cca8c..189fd4a 100644
--- a/scd/apdu.c
+++ b/scd/apdu.c
@@ -1911,6 +1911,7 @@ open_pcsc_reader_direct (const char *portstr)
   long err;
   int slot;
   char *list = NULL;
+  char *rdrname = NULL;
   pcsc_dword_t nreader;
   char *p;

@@ -1963,18 +1964,22 @@ open_pcsc_reader_direct (const char *portstr)
     {
       if (!*p && !p[1])
         break;
-      if (*p)
-        log_info ("detected reader '%s'\n", p);
+      log_info ("detected reader '%s'\n", p);
       if (nreader < (strlen (p)+1))
         {
           log_error ("invalid response from pcsc_list_readers\n");
           break;
         }
+      if (!rdrname && portstr && !strncmp (p, portstr, strlen (portstr)))
+        rdrname = p;
       nreader -= strlen (p)+1;
       p += strlen (p) + 1;
     }

-  reader_table[slot].rdrname = xtrymalloc (strlen (portstr? portstr : list)+1);
+  if (!rdrname)
+    rdrname = list;
+
+  reader_table[slot].rdrname = xtrystrdup (rdrname);
   if (!reader_table[slot].rdrname)
     {
       log_error ("error allocating memory for reader name\n");
@@ -1983,7 +1988,6 @@ open_pcsc_reader_direct (const char *portstr)
       unlock_slot (slot);
       return -1;
     }
-  strcpy (reader_table[slot].rdrname, portstr? portstr : list);
   xfree (list);
   list = NULL;

--