Created attachment 1152911 [details]
Null 01 bug

Hi, 

I have informed this bug to upstream, reporting it here just for bug tracking, thanks.

Null dereference bug in lastest git code.

0x2aaaaaceba60   <_dwarf_set_line_table_regs_default_values+112>  mov    rax,QWORD PTR [rip+0x24189]        # 0x2aaaaad0fbf0 <_dwarf_line_table_regs_default_values+80>
0x2aaaaaceba67   <_dwarf_set_line_table_regs_default_values+119>  mov    QWORD PTR [rdi+0x50],rax
0x2aaaaaceba6b   <_dwarf_set_line_table_regs_default_values+123>  ret
0x2aaaaaceba6c   nop    DWORD PTR [rax+0x0]
0x2aaaaaceba70   <_dwarf_file_name_is_full_path>  movzx  edx,BYTE PTR [rdi]              <- $pc
0x2aaaaaceba73   <_dwarf_file_name_is_full_path+3>  mov    eax,0x1
0x2aaaaaceba78   <_dwarf_file_name_is_full_path+8>  cmp    dl,0x2f
0x2aaaaaceba7b   <_dwarf_file_name_is_full_path+11>  je     0x2aaaaacebaa8 <_dwarf_file_name_is_full_path+56>
0x2aaaaaceba7d   <_dwarf_file_name_is_full_path+13>  xor    eax,eax
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------[source:./dwarf_line.c+84]--
  80     */
  81     int
  82     _dwarf_file_name_is_full_path(Dwarf_Small  *fname)
  83     {
  84         Dwarf_Small firstc = *fname;                <- $pc
  85         if (is_path_separator(firstc)) {
  86             /* Full path. */
  87             return 1;
  88         }
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------[trace]--
#0  _dwarf_file_name_is_full_path (fname=0x0) at ./dwarf_line.c:84
#1  0x00002aaaaacf40e0 in construct_at_path_from_parts (mc=0x65bff0) at dwarf_macro5.c:700
#2  dwarf_get_macro_startend_file (macro_context=macro_context@entry=0x65bff0, op_number=op_number@entry=1, line_number=line_number@entry=0x7fffffffd898, name_index_to_line_tab=name_index_to_line_tab@entry=0x7fffffffd8a0, src_file_name=src_file_name@entry=0x7fffffffd8b0, error=error@entry=0x7fffffffd8b8) at dwarf_macro5.c:774

gef> p fname
$8 = (Dwarf_Small *) 0x0
The arg (Dwarf_Small *fname) of _dwarf_file_name_is_full_path() is not checked before using.