[Bug tools/23011] New: Infinite loop in handle_sysv_hash (src/readelf.c)

traceprobe at gmail dot com sourceware-bugzilla@sourceware.org
Wed Mar 28 15:10:00 GMT 2018


https://sourceware.org/bugzilla/show_bug.cgi?id=23011

            Bug ID: 23011
           Summary: Infinite loop in handle_sysv_hash (src/readelf.c)
           Product: elfutils
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tools
          Assignee: unassigned at sourceware dot org
          Reporter: traceprobe at gmail dot com
                CC: elfutils-devel at sourceware dot org
  Target Milestone: ---

Created attachment 10920
  --> https://sourceware.org/bugzilla/attachment.cgi?id=10920&action=edit
poc for readelf

In elfutils version 0.170 and commit afffdff29228db03e2131af577f58a22aec6c1fe,
there is an infinite loop in handle_sysv_hash function of src/readelf.c, which
can be triggered by the POC below.

The issue happens since when processing System V-style hash table, the loop
value could be manipulated by input file. For instance in line 3150, if
chain[1] = 1, the program falls in infinite loop.

   3108 static void
   3109 handle_sysv_hash (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr, size_t
shstrndx)
   3110 {
   ...
   3141   for (Elf32_Word cnt = 0; cnt < nbucket; ++cnt)
   3142     {
   3143       Elf32_Word inner = bucket[cnt];
   3144       while (inner > 0 && inner < nchain)
   3145         {
   3146           ++nsyms;
   3147           if (maxlength < ++lengths[cnt])
   3148             ++maxlength;
   3149 
   3150           inner = chain[inner];
   3151         }
   3152     }

To reproduce the issue, run: ./eu-readelf -a $POC

The full stack trace is:

0x000000000040d78f in handle_sysv_hash (ebl=0x639670, scn=0x639238,
shdr=0x7fffffffdae0, shstrndx=256)
    at /home/test/test/./elfutils/master/src/src/readelf.c:3144
3144          while (inner > 0 && inner < nchain)
(gdb) bt
#0  0x000000000040d78f in handle_sysv_hash (ebl=0x639670, scn=0x639238,
shdr=0x7fffffffdae0, shstrndx=256)
    at /home/test/test/./elfutils/master/src/src/readelf.c:3144
#1  0x000000000040e24c in handle_hash (ebl=0x639670) at
/home/test/test/./elfutils/master/src/src/readelf.c:3360
#2  0x000000000040615d in process_elf_file (dwflmod=0x639340, fd=3) at
/home/test/test/./elfutils/master/src/src/readelf.c:915
#3  0x0000000000405747 in process_dwflmod (dwflmod=0x639340, userdata=0x639350,
name=0x6394e0 "poc/id:000000,src:000294,op:flip1,pos:51.", base=0,
arg=0x7fffffffdd50)
    at /home/test/test/./elfutils/master/src/src/readelf.c:707
#4  0x00007ffff7ba4c96 in dwfl_getmodules (dwfl=0x639000, callback=0x4056a9
<process_dwflmod>, arg=0x7fffffffdd50, offset=0)
    at /home/test/test/./elfutils/master/src/libdwfl/dwfl_getmodules.c:86
#5  0x0000000000405c2d in process_file (fd=3, fname=0x7fffffffe2b9
"poc/id:000000,src:000294,op:flip1,pos:51.", only_one=true)
    at /home/test/test/./elfutils/master/src/src/readelf.c:806
#6  0x000000000040461e in main (argc=3, argv=0x7fffffffdf88) at
/home/test/test/./elfutils/master/src/src/readelf.c:322

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