scd:p15: Handle cards with bad encoded path objects.

* scd/app-p15.c (read_ef_prkdf, read_ef_pukdf)
(read_ef_cdf, read_ef_aodf): Allow for a zero length path and
correctly skip unsupported auth types.
--

Signed-off-by: Werner Koch <[email protected]>
Backported-from-master: 7a8545c91b09277b0833dc0e5881ba5d1c8dbca3

1 files changed, 13 insertions, 9 deletions

diff --git a/scd/app-p15.c b/scd/app-p15.c
index 4a855b97d..131cc2cb7 100644
--- a/scd/app-p15.c
+++ b/scd/app-p15.c
@@ -1919,10 +1919,12 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
       if (err)
         goto parse_error;
 
-      /* Make sure that the next element is a non zero path and of
-         even length (FID are two bytes each). */
+      /* Make sure that the next element has a path of even length
+       * (FIDs are two bytes each).  We should check that the path
+       * length is non-zero but some cards return a zero length path
+       * nevertheless (e.g. A.E.T. Europe Java applets). */
       if (class != CLASS_UNIVERSAL || tag != TAG_OCTET_STRING
-          ||  !objlen || (objlen & 1) )
+          || (objlen & 1) )
         {
           errstr = "invalid path reference";
           goto parse_error;
@@ -2228,10 +2230,10 @@ read_ef_pukdf (app_t app, unsigned short fid, pukdf_object_t *result)
       if (err)
         goto parse_error;
 
-      /* Make sure that the next element is a non zero path and of
-         even length (FID are two bytes each). */
+      /* Make sure that the next element has a path of even length
+       * (FIDs are two bytes each).  */
       if (class != CLASS_UNIVERSAL || tag != TAG_OCTET_STRING
-          ||  !objlen || (objlen & 1) )
+          ||  (objlen & 1) )
         {
           errstr = "invalid path reference";
           goto parse_error;
@@ -2528,10 +2530,10 @@ read_ef_cdf (app_t app, unsigned short fid, int cdftype, cdf_object_t *result)
       if (err)
         goto parse_error;
 
-      /* Make sure that the next element is a non zero path and of
-         even length (FID are two bytes each). */
+      /* Make sure that the next element has a path of even length
+       * (FIDs are two bytes each).  */
       if (class != CLASS_UNIVERSAL || tag != TAG_OCTET_STRING
-          ||  !objlen || (objlen & 1) )
+          || (objlen & 1) )
         {
           errstr = "invalid path reference";
           goto parse_error;
@@ -2783,6 +2785,8 @@ read_ef_aodf (app_t app, unsigned short fid, aodf_object_t *result)
             case 2: errstr = "external auth type are not supported"; break;
             default: errstr = "unknown privateKeyObject"; break;
             }
+          p += objlen;
+          n -= objlen;
           goto parse_error;
         }
       else