Messages in this thread | | | From | Alexei Starovoitov <> | Date | Thu, 2 Apr 2020 19:46:19 -0700 | Subject | Re: [PATCH bpf] bpf, lsm: Fix the file_mprotect LSM test. |
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On Thu, Apr 2, 2020 at 1:07 PM KP Singh <kpsingh@chromium.org> wrote: > > From: KP Singh <kpsingh@google.com> > > The test was previously using an mprotect on the heap memory allocated > using malloc and was expecting the allocation to be always using > sbrk(2). This is, however, not always true and in certain conditions > malloc may end up using anonymous mmaps for heap alloctions. This means > that the following condition that is used in the "lsm/file_mprotect" > program is not sufficent to detect all mprotect calls done on heap > memory: > > is_heap = (vma->vm_start >= vma->vm_mm->start_brk && > vma->vm_end <= vma->vm_mm->brk); > > The test is updated to use an mprotect on memory allocated on the stack. > While this would result in the splitting of the vma, this happens only > after the security_file_mprotect hook. So, the condition used in the BPF > program holds true. > > Signed-off-by: KP Singh <kpsingh@google.com> > Reported-by: Alexei Starovoitov <ast@kernel.org> > Fixes: 03e54f100d57 ("bpf: lsm: Add selftests for BPF_PROG_TYPE_LSM")
Applied. Thanks
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