Re: [PATCH bpf v4 2/2] selftest/bpf: Test bpf_probe_read_user_str() strips trailing bytes after NUL

[Andrii Nakryiko]

On Thu, Nov 5, 2020 at 4:06 PM Daniel Xu <dxu@xxxxxxxxx> wrote:
>
> Previously, bpf_probe_read_user_str() could potentially overcopy the
> trailing bytes after the NUL due to how do_strncpy_from_user() does the
> copy in long-sized strides. The issue has been fixed in the previous
> commit.
>
> This commit adds a selftest that ensures we don't regress
> bpf_probe_read_user_str() again.
>
> Signed-off-by: Daniel Xu <dxu@xxxxxxxxx>
> ---

Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>

>  .../bpf/prog_tests/probe_read_user_str.c      | 71 +++++++++++++++++++
>  .../bpf/progs/test_probe_read_user_str.c      | 25 +++++++
>  2 files changed, 96 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/probe_read_user_str.c
>  create mode 100644 tools/testing/selftests/bpf/progs/test_probe_read_user_str.c
>

[...]