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Date:   Mon, 12 Nov 2018 17:52:20 -0800 (PST)
Subject:     Re: [PATCH 1/2] riscv: add audit support
In-Reply-To: <20181029104854.17432-2-david.abdurachmanov@gmail.com>
CC:     aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-audit@redhat.com,
        david.abdurachmanov@gmail.com
From:   Palmer Dabbelt <palmer@sifive.com>
To:     david.abdurachmanov@gmail.com
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On Mon, 29 Oct 2018 03:48:53 PDT (-0700), david.abdurachmanov@gmail.com wrote:
> On RISC-V (riscv) audit is supported through generic lib/audit.c.
> The patch adds required arch specific definitions.
>
> Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com>
> ---
>  arch/riscv/Kconfig                   |  1 +
>  arch/riscv/include/asm/ptrace.h      |  5 +++++
>  arch/riscv/include/asm/syscall.h     | 10 ++++++++++
>  arch/riscv/include/asm/thread_info.h |  6 ++++++
>  arch/riscv/kernel/entry.S            |  4 ++--
>  include/uapi/linux/audit.h           |  2 ++
>  6 files changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index a344980287a5..8e6d404a4ed0 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -28,6 +28,7 @@ config RISCV
>  	select GENERIC_STRNLEN_USER
>  	select GENERIC_SMP_IDLE_THREAD
>  	select GENERIC_ATOMIC64 if !64BIT || !RISCV_ISA_A
> +	select HAVE_ARCH_AUDITSYSCALL
>  	select HAVE_MEMBLOCK
>  	select HAVE_MEMBLOCK_NODE_MAP
>  	select HAVE_DMA_CONTIGUOUS
> diff --git a/arch/riscv/include/asm/ptrace.h b/arch/riscv/include/asm/ptrace.h
> index 2c5df945d43c..62c5e9d35596 100644
> --- a/arch/riscv/include/asm/ptrace.h
> +++ b/arch/riscv/include/asm/ptrace.h
> @@ -113,6 +113,11 @@ static inline void frame_pointer_set(struct pt_regs *regs,
>  	SET_FP(regs, val);
>  }
>
> +static inline unsigned long regs_return_value(struct pt_regs *regs)
> +{
> +	return regs->a0;
> +}
> +
>  #endif /* __ASSEMBLY__ */
>
>  #endif /* _ASM_RISCV_PTRACE_H */
> diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
> index 8d25f8904c00..bba3da6ef157 100644
> --- a/arch/riscv/include/asm/syscall.h
> +++ b/arch/riscv/include/asm/syscall.h
> @@ -18,6 +18,7 @@
>  #ifndef _ASM_RISCV_SYSCALL_H
>  #define _ASM_RISCV_SYSCALL_H
>
> +#include <uapi/linux/audit.h>
>  #include <linux/sched.h>
>  #include <linux/err.h>
>
> @@ -99,4 +100,13 @@ static inline void syscall_set_arguments(struct task_struct *task,
>  	memcpy(&regs->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0));
>  }
>
> +static inline int syscall_get_arch(void)
> +{
> +#ifdef CONFIG_64BIT
> +	return AUDIT_ARCH_RISCV64;
> +#else
> +	return AUDIT_ARCH_RISCV32;
> +#endif
> +}
> +
>  #endif	/* _ASM_RISCV_SYSCALL_H */
> diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
> index f8fa1cd2dad9..1c9cc8389928 100644
> --- a/arch/riscv/include/asm/thread_info.h
> +++ b/arch/riscv/include/asm/thread_info.h
> @@ -80,13 +80,19 @@ struct thread_info {
>  #define TIF_RESTORE_SIGMASK	4	/* restore signal mask in do_signal() */
>  #define TIF_MEMDIE		5	/* is terminating due to OOM killer */
>  #define TIF_SYSCALL_TRACEPOINT  6       /* syscall tracepoint instrumentation */
> +#define TIF_SYSCALL_AUDIT	7	/* syscall auditing */
>
>  #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
>  #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
>  #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
>  #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
> +#define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)
> +#define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
>
>  #define _TIF_WORK_MASK \
>  	(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED)
>
> +#define _TIF_SYSCALL_WORK \
> +	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
> +
>  #endif /* _ASM_RISCV_THREAD_INFO_H */
> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> index fa2c08e3c05e..2a6c2e7aaff3 100644
> --- a/arch/riscv/kernel/entry.S
> +++ b/arch/riscv/kernel/entry.S
> @@ -202,7 +202,7 @@ handle_syscall:
>  	REG_S s2, PT_SEPC(sp)
>  	/* Trace syscalls, but only if requested by the user. */
>  	REG_L t0, TASK_TI_FLAGS(tp)
> -	andi t0, t0, _TIF_SYSCALL_TRACE
> +	andi t0, t0, _TIF_SYSCALL_WORK
>  	bnez t0, handle_syscall_trace_enter
>  check_syscall_nr:
>  	/* Check to make sure we don't jump to a bogus syscall number. */
> @@ -222,7 +222,7 @@ ret_from_syscall:
>  	REG_S a0, PT_A0(sp)
>  	/* Trace syscalls, but only if requested by the user. */
>  	REG_L t0, TASK_TI_FLAGS(tp)
> -	andi t0, t0, _TIF_SYSCALL_TRACE
> +	andi t0, t0, _TIF_SYSCALL_WORK
>  	bnez t0, handle_syscall_trace_exit
>
>  ret_from_exception:
> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> index 818ae690ab79..d0e037a96a7b 100644
> --- a/include/uapi/linux/audit.h
> +++ b/include/uapi/linux/audit.h
> @@ -399,6 +399,8 @@ enum {
>  /* do not define AUDIT_ARCH_PPCLE since it is not supported by audit */
>  #define AUDIT_ARCH_PPC64	(EM_PPC64|__AUDIT_ARCH_64BIT)
>  #define AUDIT_ARCH_PPC64LE	(EM_PPC64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
> +#define AUDIT_ARCH_RISCV32	(EM_RISCV|__AUDIT_ARCH_LE)
> +#define AUDIT_ARCH_RISCV64	(EM_RISCV|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
>  #define AUDIT_ARCH_S390		(EM_S390)
>  #define AUDIT_ARCH_S390X	(EM_S390|__AUDIT_ARCH_64BIT)
>  #define AUDIT_ARCH_SH		(EM_SH)

I can't seem to figure out how to dig the rest of the thread out of my inbox 
(I'm in an airport), so I'm just replying here.

I've added this to next-audit, which will soon filter into for-next.  I'm not 
sure if this is 100% settled, but I can't find any issues with it so I think 
it's best to get this out for testing.