Created attachment 1150561 [details]
bad elf that trigger this bug

Description of problem:
There is a NULL pointer dereference bug in libdwarf-20160115 and latest git code.

The bug is at file dwarf_leb.c:147
 143             byte_length++;
 144             if (byte_length > BYTESLEBMAX) {
 145                 /*  Erroneous input. What to do?
 146                     Abort? Return error? Just stop here?*/
 147                 *leb128_length = BYTESLEBMAX;               <- $pc
 148                 return number;
 149             }
 150         }

which triggered by dwarf_form.c:918
 913             *return_sval = (Dwarf_Signed) ret_value;
 914             return DW_DLV_OK;
 915             }
 916
 917         case DW_FORM_sdata:
 918             ret_value =
 919                 (_dwarf_decode_s_leb128(attr->ar_debug_ptr, NULL));
 920             *return_sval = ret_value;
 921             return DW_DLV_OK;
 922


Version-Release number of selected component (if applicable):
Tested in libdwarf-20160115 and latest git code

How reproducible:
Use the attachment:
$ dwarfdump <extracted attachment>

Actual results:
...
Segmentation Fault