Re: Is PIE randomization breaking klibc binaries?

Chuck Ebbert
2007-07-24T20:58:18Z

On 07/24/2007 04:34 PM, Chuck Ebbert wrote:
> On 07/20/2007 06:05 PM, H. Peter Anvin wrote:
>>> It looks like that the PIE randomization patch breaks klibc
>>> binaries on x86-64.
>>>
>> Interesting.
>>
>> klibc binaries are indeed statically linked, but composed of two
>> different ELF images: the application itself and the shared libary
>> (which is referenced from the application header as the "interpreter").
>> Neither of these is an ET_DYN file; they are both ET_EXEC, so it
>> *should* be unaffected by the PIE randomization patch. Obviously, that
>> seems to not be the case.
>>
>> My guess is that this patch mishandles interpreter images which are
>> ET_EXEC. Jan, any insight?
>
> Well, they don't run on Fedora 6 either (which has the same code, it's
> part of exec-shield):
>
> $ strace ./cat
> execve("./cat", ["./cat"], [/* 55 vars */]) = -1 ENOENT (No such file or directory)
> ...
> $ file cat
> cat: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked (uses shared libs), stripped
>
> Funny nobody noticed that before...
>

After installing klibc.so and klibc-<ID>.so into /lib everything works:

Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
PHDR 0x000034 0x08048034 0x08048034 0x0000a0 0x0000a0 R E 0x4
INTERP 0x0000d4 0x080480d4 0x080480d4 0x00002a 0x00002a R 0x1
[Requesting program interpreter: /lib/klibc-58kBUyV_qhVvkMnaxy8A7N8rLak.so]

Ulrich, did your initrd contain the correct .so? Did you try rebuilding klibc after
building the new kernel?