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

From: Palmer Dabbelt
Date: Mon Nov 12 2018 - 20:52:25 EST


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.