throw the new FieldError exception, if a dissector tries to add a field with invalid parameters

add a message parameter to the show_exception function

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@13074 f5534014-38df-0310-8fa8-9805f1628bb7

11 files changed, 31 insertions, 13 deletions

diff --git a/epan/dissectors/packet-acse.c b/epan/dissectors/packet-acse.c
index da96e6c636..1ba1eb52ea 100644
--- a/epan/dissectors/packet-acse.c
+++ b/epan/dissectors/packet-acse.c
@@ -228,7 +228,7 @@ call_app_dissector(tvbuff_t *tvb, gint offset, gint param_len,
 			}
 			CATCH_ALL
 			{
-				show_exception(tvb, pinfo, tree, EXCEPT_CODE);
+				show_exception(tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
 			}
 			ENDTRY;
 	}
diff --git a/epan/dissectors/packet-dcerpc.c b/epan/dissectors/packet-dcerpc.c
index 33860a8c58..8f378322eb 100644
--- a/epan/dissectors/packet-dcerpc.c
+++ b/epan/dissectors/packet-dcerpc.c
@@ -2108,7 +2108,7 @@ else
                 } CATCH(BoundsError) {
                     RETHROW;
                 } CATCH_ALL {
-                    show_exception(decrypted_tvb, pinfo, tree, EXCEPT_CODE);
+                    show_exception(decrypted_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
                 } ENDTRY;
             }
 
@@ -2168,7 +2168,7 @@ dissect_dcerpc_verifier (tvbuff_t *tvb, packet_info *pinfo,
 		dissect_auth_verf(auth_tvb, pinfo, dcerpc_tree, auth_fns,
 				  hdr, auth_info);
 	    } CATCH_ALL {
-		show_exception(auth_tvb, pinfo, dcerpc_tree, EXCEPT_CODE);
+		show_exception(auth_tvb, pinfo, dcerpc_tree, EXCEPT_CODE, GET_MESSAGE);
 	    } ENDTRY;
 	} else {
 	    proto_tree_add_text (dcerpc_tree, auth_tvb, 0, hdr->auth_len,
@@ -2269,7 +2269,7 @@ dissect_dcerpc_cn_auth (tvbuff_t *tvb, int stub_offset, packet_info *pinfo,
                    padding is actually inside the encrypted stub */
                    auth_info->auth_size = hdr->auth_len + 8;
             } CATCH_ALL {
-                show_exception(tvb, pinfo, dcerpc_tree, EXCEPT_CODE);
+                show_exception(tvb, pinfo, dcerpc_tree, EXCEPT_CODE, GET_MESSAGE);
             } ENDTRY;
         }
     }
diff --git a/epan/dissectors/packet-ethertype.c b/epan/dissectors/packet-ethertype.c
index 93933100be..60a058c3c0 100644
--- a/epan/dissectors/packet-ethertype.c
+++ b/epan/dissectors/packet-ethertype.c
@@ -208,7 +208,7 @@ ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 		   to show the trailer, after noting that a dissector was
 		   found and restoring the protocol value that was in effect
 		   before we called the subdissector. */
-		show_exception(next_tvb, pinfo, tree, EXCEPT_CODE);
+		show_exception(next_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
 		dissector_found = TRUE;
 		pinfo->current_proto = saved_proto;
 	}
diff --git a/epan/dissectors/packet-frame.c b/epan/dissectors/packet-frame.c
index 29efbc76c5..0716595f72 100644
--- a/epan/dissectors/packet-frame.c
+++ b/epan/dissectors/packet-frame.c
@@ -194,7 +194,7 @@ dissect_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 		}
 	}
 	CATCH_ALL {
-		show_exception(tvb, pinfo, tree, EXCEPT_CODE);
+		show_exception(tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
 	}
 	ENDTRY;
 
@@ -206,7 +206,7 @@ dissect_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 
 void
 show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
-    unsigned long exception)
+    unsigned long exception, const char *exception_message)
 {
 	switch (exception) {
 
@@ -220,6 +220,18 @@ show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 	case ReportedBoundsError:
 		show_reported_bounds_error(tvb, pinfo, tree);
 		break;
+    case FieldError:
+		if (check_col(pinfo->cinfo, COL_INFO))
+			col_append_str(pinfo->cinfo, COL_INFO, "[Dissector Bug]");
+		proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
+				"[FieldError: %s]", exception_message);
+        g_warning("FieldError in packet: %u (%s)", pinfo->fd->num, exception_message);
+        if(exception_message)
+            g_free( (void *) exception_message);
+        break;
+    default:
+        /* XXX - we want to know, if an unknown exception passed until here, don't we? */
+        g_assert_not_reached();
 	}
 }
 
diff --git a/epan/dissectors/packet-frame.h b/epan/dissectors/packet-frame.h
index f5a135956b..1430fb1544 100644
--- a/epan/dissectors/packet-frame.h
+++ b/epan/dissectors/packet-frame.h
@@ -27,7 +27,7 @@
  * Routine used to add an indication of an arbitrary exception to the tree.
  */
 void show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
-    unsigned long exception);
+    unsigned long exception, const char *exception_message);
 
 /*
  * Routine used to add an indication of a ReportedBoundsError exception
diff --git a/epan/dissectors/packet-ieee8023.c b/epan/dissectors/packet-ieee8023.c
index 5e8f98aa2d..55853d9d15 100644
--- a/epan/dissectors/packet-ieee8023.c
+++ b/epan/dissectors/packet-ieee8023.c
@@ -102,7 +102,7 @@ dissect_802_3(int length, gboolean is_802_2, tvbuff_t *tvb,
        Show the exception, and then drive on to show the trailer,
        restoring the protocol value that was in effect before we
        called the subdissector. */
-    show_exception(next_tvb, pinfo, tree, EXCEPT_CODE);
+    show_exception(next_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
     pinfo->current_proto = saved_proto;
   }
   ENDTRY;
diff --git a/epan/dissectors/packet-isl.c b/epan/dissectors/packet-isl.c
index c1544dc611..44e099de55 100644
--- a/epan/dissectors/packet-isl.c
+++ b/epan/dissectors/packet-isl.c
@@ -287,7 +287,7 @@ dissect_isl(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int fcs_len)
            Show the exception, and then drive on to show the trailer,
            restoring the protocol value that was in effect before we
            called the subdissector. */
-        show_exception(next_tvb, pinfo, tree, EXCEPT_CODE);
+        show_exception(next_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
         pinfo->current_proto = saved_proto;
       }
       ENDTRY;
diff --git a/epan/dissectors/packet-pres.c b/epan/dissectors/packet-pres.c
index d12218316e..b692101ae7 100644
--- a/epan/dissectors/packet-pres.c
+++ b/epan/dissectors/packet-pres.c
@@ -242,7 +242,7 @@ call_acse_dissector(tvbuff_t *tvb, gint offset, gint param_len,
 		}
 		CATCH_ALL
 		{
-			show_exception(tvb, pinfo, tree, EXCEPT_CODE);
+			show_exception(tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
 		}
 		ENDTRY;
 	}
diff --git a/epan/dissectors/packet-ses.c b/epan/dissectors/packet-ses.c
index b7e792769a..fe34919adf 100644
--- a/epan/dissectors/packet-ses.c
+++ b/epan/dissectors/packet-ses.c
@@ -298,7 +298,7 @@ call_pres_dissector(tvbuff_t *tvb, int offset, guint16 param_len,
 		}
 		CATCH_ALL
 		{
-			show_exception(tvb, pinfo, tree, EXCEPT_CODE);
+			show_exception(tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
 		}
 		ENDTRY;
 	}
diff --git a/epan/exceptions.h b/epan/exceptions.h
index a16b892565..343794382e 100644
--- a/epan/exceptions.h
+++ b/epan/exceptions.h
@@ -12,6 +12,7 @@
 #define BoundsError		1	/* Index is out of range */
 #define ReportedBoundsError	2	/* Index is beyond reported length (not cap_len) */
 #define TypeError		3	/* During dfilter parsing */
+#define FieldError		4	/* A buggy dissector tried to add a field with invalid parameters */
 
 /* Usage:
  *
diff --git a/epan/proto.c b/epan/proto.c
index 58538d49cb..100e7dd138 100644
--- a/epan/proto.c
+++ b/epan/proto.c
@@ -2002,6 +2002,7 @@ alloc_field_info(proto_tree *tree, int hfindex, tvbuff_t *tvb, gint start,
 {
 	header_field_info	*hfinfo;
 	field_info		*fi;
+    gchar           *error_descr;
 
 	/*
 	 * We only allow a null tvbuff if the item has a zero length,
@@ -2092,7 +2093,11 @@ alloc_field_info(proto_tree *tree, int hfindex, tvbuff_t *tvb, gint start,
 			g_assert_not_reached();
 		}
 	} else
-		g_assert(*length >= 0);
+	    if(*length < 0) {
+          error_descr = g_strdup_printf("\"%s\" - \"%s\" invalid length: %d %s/%u", 
+              hfinfo->name, hfinfo->abbrev, *length, __FILE__, __LINE__);
+          THROW_MESSAGE(FieldError, error_descr);
+        }
 
 	FIELD_INFO_NEW(fi);