[AUDIT] Don't allow ptrace to fool auditing, log arch of audited syscalls.

We were calling ptrace_notify() after auditing the syscall and arguments,
but the debugger could have _changed_ them before the syscall was actually
invoked. Reorder the calls to fix that.

While we're touching ever call to audit_syscall_entry(), we also make it
take an extra argument: the architecture of the syscall which was made,
because some architectures allow more than one type of syscall.

Also add an explicit success/failure flag to audit_syscall_exit(), for
the benefit of architectures which return that in a condition register
rather than only returning a single register.

Change type of syscall return value to 'long' not 'int'.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 28 insertions, 10 deletions

diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 92f2c39..eaf7be9 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -300,25 +300,38 @@ out:
 	return ret;
 }
 
+static inline int audit_arch()
+{
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+#ifdef CONFIG_MIPS64
+	if (!(current->thread.mflags & MF_32BIT_REGS))
+		return AUDIT_ARCH_MIPSEL64;
+#endif /* MIPS64 */
+	return AUDIT_ARCH_MIPSEL;
+
+#else /* big endian... */
+#ifdef CONFIG_MIPS64
+	if (!(current->thread.mflags & MF_32BIT_REGS))
+		return AUDIT_ARCH_MIPS64;
+#endif /* MIPS64 */
+	return AUDIT_ARCH_MIPS;
+
+#endif /* endian */
+}
+
 /*
  * Notification of system call entry/exit
  * - triggered by current->work.syscall_trace
  */
 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(current, regs->regs[2],
-			                    regs->regs[4], regs->regs[5],
-			                    regs->regs[6], regs->regs[7]);
-		else
-			audit_syscall_exit(current, regs->regs[2]);
-	}
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]), regs->regs[2]);
 
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
+		goto out;
 	if (!(current->ptrace & PT_PTRACED))
-		return;
+		goto out;
 
 	/* The 0x80 provides a way for the tracing parent to distinguish
 	   between a syscall stop and SIGTRAP delivery */
@@ -334,4 +347,9 @@ asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 		send_sig(current->exit_code, current, 1);
 		current->exit_code = 0;
 	}
+ out:
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(current, audit_arch(), regs->regs[2],
+				    regs->regs[4], regs->regs[5],
+				    regs->regs[6], regs->regs[7]);
 }