[compiler-rt] r303132 - [asan] make asan under sandboxes more robust

[Peter Collingbourne via llvm-commits]

I think it's not just a matter of a new enough kernel but the fact that
some Linux distributions disable user namespaces for security reasons, e.g.
Arch Linux: https://bugs.archlinux.org/task/36969

Peter

On Mon, May 15, 2017 at 5:03 PM, Kostya Serebryany <kcc at google.com> wrote:

> Yea, probably.
> Will this include fresh enough kernels that we care about?
>
> On Mon, May 15, 2017 at 4:54 PM, Peter Collingbourne <peter at pcc.me.uk>
> wrote:
>
>> The test will fail if the kernel does not allow user namespaces, won't it?
>>
>> Peter
>>
>> On Mon, May 15, 2017 at 4:37 PM, Kostya Serebryany via llvm-commits <
>> llvm-commits at lists.llvm.org> wrote:
>>
>>> Author: kcc
>>> Date: Mon May 15 18:37:54 2017
>>> New Revision: 303132
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=303132&view=rev
>>> Log:
>>> [asan] make asan under sandboxes more robust
>>>
>>> Added:
>>>     compiler-rt/trunk/test/asan/TestCases/Linux/sanbox_read_proc
>>> _self_maps_test.cc
>>> Modified:
>>>     compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_linux.cc
>>>
>>> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_li
>>> nux.cc
>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sa
>>> nitizer_common/sanitizer_procmaps_linux.cc?rev=303132&r1=303
>>> 131&r2=303132&view=diff
>>> ============================================================
>>> ==================
>>> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_linux.cc
>>> (original)
>>> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_linux.cc
>>> Mon May 15 18:37:54 2017
>>> @@ -18,8 +18,8 @@
>>>  namespace __sanitizer {
>>>
>>>  void ReadProcMaps(ProcSelfMapsBuff *proc_maps) {
>>> -  CHECK(ReadFileToBuffer("/proc/self/maps", &proc_maps->data,
>>> -                         &proc_maps->mmaped_size, &proc_maps->len));
>>> +  ReadFileToBuffer("/proc/self/maps", &proc_maps->data,
>>> &proc_maps->mmaped_size,
>>> +                   &proc_maps->len);
>>>  }
>>>
>>>  static bool IsOneOf(char c, char c1, char c2) {
>>>
>>> Added: compiler-rt/trunk/test/asan/TestCases/Linux/sanbox_read_proc
>>> _self_maps_test.cc
>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/a
>>> san/TestCases/Linux/sanbox_read_proc_self_maps_test.cc?rev=
>>> 303132&view=auto
>>> ============================================================
>>> ==================
>>> --- compiler-rt/trunk/test/asan/TestCases/Linux/sanbox_read_proc_self_maps_test.cc
>>> (added)
>>> +++ compiler-rt/trunk/test/asan/TestCases/Linux/sanbox_read_proc_self_maps_test.cc
>>> Mon May 15 18:37:54 2017
>>> @@ -0,0 +1,30 @@
>>> +// REQUIRES: x86_64-target-arch
>>> +// RUN: %clangxx_asan  %s -o %t
>>> +// RUN: not %run %t 2>&1 | FileCheck %s
>>> +#include <sanitizer/common_interface_defs.h>
>>> +#include <sched.h>
>>> +#include <unistd.h>
>>> +#include <stdio.h>
>>> +#include <stdlib.h>
>>> +
>>> +int main() {
>>> +  __sanitizer_sandbox_arguments args = {0};
>>> +  // should cache /proc/self/maps
>>> +  __sanitizer_sandbox_on_notify(&args);
>>> +
>>> +  if (unshare(CLONE_NEWUSER)) {
>>> +    printf("unshare failed\n");
>>> +    abort();
>>> +  }
>>> +
>>> +  // remove access to /proc/self/maps
>>> +  if (chroot("/tmp")) {
>>> +    printf("chroot failed\n");
>>> +    abort();
>>> +  }
>>> +
>>> +  *(volatile int*)0x42 = 0;
>>> +// CHECK: AddressSanitizer: SEGV on unknown address 0x000000000042
>>> +// CHECK-NOT: AddressSanitizer CHECK failed
>>> +// CHECK: SUMMARY: AddressSanitizer: SEGV
>>> +}
>>>
>>>
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>>>
>>
>>
>>
>> --
>> --
>> Peter
>>
>
>


-- 
-- 
Peter
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