Bug 22373

Created attachment 10560 [details]
POC of the crash

Triggered by "./objdump -x $POC"
Tested on Ubuntu 16.04 (x86)


Integer overflow is occurring when checking size of debug directory of the PE format binary file.


The GDB debugging information is as follows:

(gdb) r -x $POC

Program received signal SIGSEGV, Segmentation fault.
0x080c55f5 in bfd_getl32 (p=0x8276000) at libbfd.c:557
557	  v = (unsigned long) addr[0];
(gdb) bt
#0  0x080c55f5 in bfd_getl32 (p=0x8276000) at libbfd.c:557
#1  0x08155ff6 in _bfd_pei_swap_debugdir_in (abfd=0x8255a08, ext1=0x8276000, in1=0xbfffe168) at peigen.c:1119
#2  0x0814d8e6 in pe_bfd_read_buildid (abfd=0x8255a08) at ./peicode.h:1353
#3  0x0814b813 in pe_bfd_object_p (abfd=0x8255a08) at ./peicode.h:1497
#4  0x080c323c in bfd_check_format_matches (abfd=0x8255a08, format=bfd_object, matching=0xbfffedb0) at format.c:311
#5  0x0804b5be in display_object_bfd (abfd=0x8255a08) at ./objdump.c:3609
#6  0x0804b587 in display_any_bfd (file=0x8255a08, level=0) at ./objdump.c:3700
#7  0x0804b2b1 in display_file (
    filename=0xbffff257 "/home/min/fuzzing/result/binutils/objdump_x_D_s_pe_1/crashes/id:000015,sig:06,src:000270,op:havoc,rep:64", target=0x0, last_file=1) at ./objdump.c:3721
#8  0x0804ae80 in main (argc=3, argv=0xbffff044) at ./objdump.c:4023


Proposed patch:

--- a/bfd/peicode.h
+++ b/bfd/peicode.h
@@ -1328,7 +1328,7 @@ pe_bfd_read_buildid (bfd *abfd)
   dataoff = addr - section->vma;
 
   /* PR 20605: Make sure that the data is really there.  */
-  if (dataoff + size > section->size)
+  if (size > section->size - dataoff)
     {
       _bfd_error_handler (_("%B: Error: Debug Data ends beyond end of debug directory."),
                          abfd);


Credits:

This vulnerability was discovered by Mingi Cho and Taekyoung Kwon of the Information Security Lab, Yonsei University. Please contact mgcho.minic@gmail.com and taekyoung@yonsei.ac.kr if you need more information about the vulnerability and the lab.