Re: [libredwg] [bug #28858] Segfaults on DWG file

[Felipe Sanches]

hi, guys,

The file attached to this bug report caught my attention to 2 bugs in our
description of the dwg spec. The patch attached fixes these 2 bugs and thus
results in the file being properly parsed by LibreDWG.

As you can see in this part of the output I've got, all 14.778 objects of
the dwg file were properly parsed, but now we have another issue: a segfault
in the application itself (testSVG.c) instead of in the lib:


Num objects: 14778
ERROR: Decoding of DWG version R2004 header is not fully implemented yet. We
are going to try
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
   xmlns:svg="http://www.w3.org/2000/svg";
   xmlns="http://www.w3.org/2000/svg";
   xmlns:xlink="http://www.w3.org/1999/xlink";
   version="1.1"
   width="675557.074791"
   height="287180.897189"
>
    <defs>

Program received signal SIGSEGV, Segmentation fault.
output_BLOCK_HEADER (ref=<value optimized out>) at testSVG.c:197
197      hdr = ref->obj->tio.object->tio.BLOCK_HEADER;
(gdb)



I am having some trouble with git recently.
Pitanga, please apply this attached patch to your local copy and push it to
git master

Then I'll continue investigating what's causing this testSVG SegFault

-Felipe

<http://savannah.gnu.org/bugs/?28858>

diff --git a/src/decode.c b/src/decode.c
index 1b9b3b2..e9c2c6e 100644
--- a/src/decode.c
+++ b/src/decode.c
@@ -2169,6 +2169,13 @@ dwg_decode_handleref_with_code(Bit_Chain * dat, Dwg_Object * obj, Dwg_Data* dwg,
 {
   Dwg_Object_Ref * ref;
   ref = dwg_decode_handleref(dat, obj, dwg);
+
+  if (!ref)
+    {
+      LOG_ERROR("dwg_decode_handleref_with_code: ref is a null pointer\n");
+      return 0;
+    }
+
   if (ref->absolute_ref == 0 && ref->handleref.code != code)
     {
       LOG_ERROR("Expected a CODE %d handle, got a %d\n", code, ref->handleref.code)
diff --git a/src/dwg.h b/src/dwg.h
index 13f2b51..94413d3 100644
--- a/src/dwg.h
+++ b/src/dwg.h
@@ -1272,7 +1272,7 @@ typedef struct _dwg_entity_LEADER
   BITCODE_3DPOINT end_pt_proj;
   BITCODE_3DPOINT extrusion;
   BITCODE_3DPOINT x_direction;
-  BITCODE_3DPOINT offset_block_inspt;
+  BITCODE_3DPOINT offset_to_block_ins_pt;
   BITCODE_3DPOINT unknown_pt;
   BITCODE_BD dimgap;
   BITCODE_BD box_height;
@@ -2220,7 +2220,7 @@ typedef struct _dwg_object_RASTERVARIABLES
 typedef struct _dwg_object_SORTENTSTABLE
 {
   BITCODE_BL num_entries;
-  BITCODE_H sort_handle;
+  BITCODE_H* sort_handles;
   BITCODE_H parenthandle;
   BITCODE_H* reactors;
   BITCODE_H xdicobjhandle;
diff --git a/src/dwg.spec b/src/dwg.spec
index b2103d4..88b35a3 100644
--- a/src/dwg.spec
+++ b/src/dwg.spec
@@ -1465,6 +1465,7 @@ DWG_ENTITY(LEADER);
   FIELD_3DPOINT(end_pt_proj);
   FIELD_3DPOINT(extrusion);
   FIELD_3DPOINT(x_direction);
+  FIELD_3DPOINT(offset_to_block_ins_pt);
 
   SINCE(R_14)
     {
@@ -2702,7 +2703,7 @@ DWG_OBJECT_END
 DWG_OBJECT(SORTENTSTABLE);
 
   FIELD_BL (num_entries);
-  FIELD_HANDLE (sort_handle, 0);
+  HANDLE_VECTOR (sort_handles, num_entries, 0);
   FIELD_HANDLE (parenthandle, 4);
   REACTORS(4);
   XDICOBJHANDLE(3);