Re: [PATCH 1/2] riscv: add audit support

From: Palmer Dabbelt
Date: Wed Nov 14 2018 - 18:40:57 EST

On Tue, 13 Nov 2018 15:34:18 PST (-0800), paul@xxxxxxxxxxxxxx wrote:
On Tue, Nov 13, 2018 at 5:07 AM Palmer Dabbelt <palmer@xxxxxxxxxx> wrote:
On Mon, 29 Oct 2018 03:48:53 PDT (-0700), david.abdurachmanov@xxxxxxxxx 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@xxxxxxxxx>
> ---
> 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.

If you RISCV guys are happy, and it is passing the audit-testsuite
(which I believe it is based on some brief discussions with David on
Freenode), then I think it is okay from my point of view.

I haven't run the test suite personally, but I trust that David has done so if he said so (I remember having seen him say he did as well).

Thanks!