Re: [PATCH v5 0/3] arm64: Add seccomp support

From: Kees Cook
Date: Tue Jul 22 2014 - 16:16:52 EST


On Tue, Jul 22, 2014 at 2:14 AM, AKASHI Takahiro
<takahiro.akashi@xxxxxxxxxx> wrote:
> (Please apply this patch after my audit patch in order to avoid some
> conflict on arm64/Kconfig.)
>
> This patch enables secure computing (system call filtering) on arm64.
> System calls can be allowed or denied by loaded bpf-style rules.
> Architecture specific part is to run secure_computing() on syscall entry
> and check the result. See [3/3]

Thanks for working on this!

> Prerequisites are:
> * "arm64: Add audit support" patch
>
> This code is tested on ARMv8 fast model using
> * libseccomp v2.1.1 with modifications for arm64 and verified by its "live"
> tests, 20, 21 and 24.
> * modified version of Kees' seccomp test for 'changing/skipping a syscall'
> behavior

Would you be able to share this? I'd love to add it to the seccomp
regression suite for the arm64-specific parts.

Thanks!

-Kees

>
> Changes v4 -> v5:
> * rebased to v3.16-rc
> * add patch [1/3] to allow ptrace to change a system call
> (please note that this patch should be applied even without seccomp.)
>
> Changes v3 -> v4:
> * removed the following patch and moved it to "arm64: prerequisites for
> audit and ftrace" patchset since it is required for audit and ftrace in
> case of !COMPAT, too.
> "arm64: is_compat_task is defined both in asm/compat.h and linux/compat.h"
>
> Changes v2 -> v3:
> * removed unnecessary 'type cast' operations [2/3]
> * check for a return value (-1) of secure_computing() explicitly [2/3]
> * aligned with the patch, "arm64: split syscall_trace() into separate
> functions for enter/exit" [2/3]
> * changed default of CONFIG_SECCOMP to n [2/3]
>
> Changes v1 -> v2:
> * added generic seccomp.h for arm64 to utilize it [1,2/3]
> * changed syscall_trace() to return more meaningful value (-EPERM)
> on seccomp failure case [2/3]
> * aligned with the change in "arm64: make a single hook to syscall_trace()
> for all syscall features" v2 [2/3]
> * removed is_compat_task() definition from compat.h [3/3]
>
> AKASHI Takahiro (3):
> arm64: ptrace: reload a syscall number after ptrace operations
> asm-generic: Add generic seccomp.h for secure computing mode 1
> arm64: Add seccomp support
>
> arch/arm64/Kconfig | 14 ++++++++++++++
> arch/arm64/include/asm/seccomp.h | 25 +++++++++++++++++++++++++
> arch/arm64/include/asm/unistd.h | 3 +++
> arch/arm64/kernel/entry.S | 2 ++
> arch/arm64/kernel/ptrace.c | 18 ++++++++++++++++++
> include/asm-generic/seccomp.h | 28 ++++++++++++++++++++++++++++
> 6 files changed, 90 insertions(+)
> create mode 100644 arch/arm64/include/asm/seccomp.h
> create mode 100644 include/asm-generic/seccomp.h
>
> --
> 1.7.9.5
>



--
Kees Cook
Chrome OS Security
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