Re: out-of-bounds read / crash in elfutils tools (readelf, nm, ...) with malformed file

[Mark Wielaard <mjw@redhat.com>]

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On Thu, Nov 13, 2014 at 08:39:32PM +0100, Hanno Böck wrote:
> Am Thu, 13 Nov 2014 15:45:26 +0100
> schrieb Mark Wielaard <mjw@redhat.com>:
> 
> > I pushed this now to master as attached.
> 
> still crashes readelf -a in
> id:000116,src:000000,op:flip32,pos:5554

> Program received signal SIGSEGV, Segmentation fault.
> 0xf7d96112 in vfprintf () from /lib32/libc.so.6

Sorry, you'll have to dig into that one a bit deeper yourself, since it
doesn't crash for me, even on a (Fedora 21 beta) i686 setup.

Maybe you could install debuginfo for glibc and see what is being
passed to printf that seem to cause it to crash.

> (gdb) bt
> #0  0xf7d96112 in vfprintf () from /lib32/libc.so.6
> #1  0xf7d9c5c8 in printf () from /lib32/libc.so.6
> #2  0x0805163c in handle_symtab (ebl=0x8078b58, scn=0x807a140,
> shdr=0xffffca5c) at readelf.c:2245
> #3  0x08050fbb in print_symtab (ebl=0x8078b58, type=2) at readelf.c:2139
> #4  0x0804cb06 in process_elf_file (dwflmod=0x80789e8, fd=3) at
> readelf.c:887 #5  0x0804c1f4 in process_dwflmod (dwflmod=0x80789e8,
> userdata=0x80789f0, name=0x8078af8
> "id:000116,src:000000,op:flip32,pos:5554", base=134512640,
> arg=0xffffcc8c) at readelf.c:691 #6  0xf7f38be4 in dwfl_getmodules ()
> from /usr/lib32/libdw.so.1 #7  0x0804c66a in process_file (fd=3, 
>     fname=0xffffcfe6 "id:000116,src:000000,op:flip32,pos:5554",
> only_one=true) at readelf.c:790
> #8  0x0804b13f in main (argc=3, argv=0xffffce04) at readelf.c:296

Are you sure you are using the git master sources?
The backtrace looks like it is using the system installed libdw.so.

Thanks,

Mark