Messages in this thread | | | Subject | Re: [PATCH v2 1/4] bpf: Add support for reading user pointers | From | Daniel Borkmann <> | Date | Tue, 7 May 2019 01:10:45 +0200 |
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On 05/06/2019 09:57 PM, Joel Fernandes wrote: > On Mon, May 06, 2019 at 09:11:19PM +0200, Daniel Borkmann wrote: >> On 05/06/2019 08:31 PM, Joel Fernandes (Google) wrote: >>> The eBPF based opensnoop tool fails to read the file path string passed >>> to the do_sys_open function. This is because it is a pointer to >>> userspace address and causes an -EFAULT when read with >>> probe_kernel_read. This is not an issue when running the tool on x86 but >>> is an issue on arm64. This patch adds a new bpf function call based >>> which calls the recently proposed probe_user_read function [1]. >>> Using this function call from opensnoop fixes the issue on arm64. >>> >>> [1] https://lore.kernel.org/patchwork/patch/1051588/ >>> >>> Cc: Michal Gregorczyk <michalgr@live.com> >>> Cc: Adrian Ratiu <adrian.ratiu@collabora.com> >>> Cc: Mohammad Husain <russoue@gmail.com> >>> Cc: Qais Yousef <qais.yousef@arm.com> >>> Cc: Srinivas Ramana <sramana@codeaurora.org> >>> Cc: duyuchao <yuchao.du@unisoc.com> >>> Cc: Manjo Raja Rao <linux@manojrajarao.com> >>> Cc: Karim Yaghmour <karim.yaghmour@opersys.com> >>> Cc: Tamir Carmeli <carmeli.tamir@gmail.com> >>> Cc: Yonghong Song <yhs@fb.com> >>> Cc: Alexei Starovoitov <ast@kernel.org> >>> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> >>> Cc: Masami Hiramatsu <mhiramat@kernel.org> >>> Cc: Peter Ziljstra <peterz@infradead.org> >>> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> >>> Cc: Steven Rostedt <rostedt@goodmis.org> >>> Cc: Kees Cook <keescook@chromium.org> >>> Cc: kernel-team@android.com >>> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> >>> --- >>> Masami, could you carry these patches in the series where are you add >>> probe_user_read function? >>> >>> Previous submissions is here: >>> https://lore.kernel.org/patchwork/patch/1069552/ >>> v1->v2: split tools uapi sync into separate commit, added deprecation >>> warning for old bpf_probe_read function. >> >> Please properly submit this series to bpf tree once the base >> infrastructure from Masami is upstream. > > Could you clarify what do you mean by "properly submit this series to bpf > tree" mean? bpf@vger.kernel.org is CC'd.
Yeah, send the BPF series to bpf@vger.kernel.org once Masami's patches have hit mainline, and we'll then route yours as fixes the usual path through bpf tree.
>> This series here should >> also fix up all current probe read usage under samples/bpf/ and >> tools/testing/selftests/bpf/. > > Ok. Agreed, will do that.
Great, thanks! Daniel
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