Re: [PATCH] Audit: push audit success and retcode into arch ptrace.h

On 06/02/2011 06:32 PM, Richard Weinberger wrote:

Am Donnerstag 02 Juni 2011, 23:04:58 schrieb Eric Paris:

quoted

b/arch/um/sys-i386/shared/sysdep/ptrace.h index d50e62e..ef5c310 100644

--- a/arch/um/sys-i386/shared/sysdep/ptrace.h
+++ b/arch/um/sys-i386/shared/sysdep/ptrace.h

@@ -162,6 +162,7 @@ struct syscall_args {
 #define UPT_ORIG_SYSCALL(r) UPT_EAX(r)
 #define UPT_SYSCALL_NR(r) UPT_ORIG_EAX(r)
 #define UPT_SYSCALL_RET(r) UPT_EAX(r)
+#define regs_return_value UPT_SYSCALL_RET

This does not work at all.
UPT_SYSCALL_RET expects something of type struct uml_pt_regs.

#define regs_return_value REGS_EAX
Would be correct. (For x86_64 it needs to be REGS_RAX)

But there seems to be another problem.
Why is pt_regs of type void *?

I was stupid and used #define's instead of static inlines.  Sorry.  I
wonder how many other arches I got that wrong, i'm sure others....

The code in arch/um/kernel/ptrace.c::syscall_trace() appeared to have a
uml_pt_regs instead of just pt_regs.  Which was why audit_syscall_exit()
takes a void * instead of a pt_regs.  We pass that right back to
regs_return_value().  I believe the correct code should be:

static inline long regs_return_value(struct uml_pt_regs *r)
{
	return UPT_SYSCALL_RET(r);
}

gcc complains:
In file included from include/linux/fsnotify.h:15:0,
                 from include/linux/security.h:26,
                 from init/main.c:32:
include/linux/audit.h: In function ‘audit_syscall_exit’:
include/linux/audit.h:440:17: warning: dereferencing ‘void *’ pointer
include/linux/audit.h:440:3: error: invalid use of void expression
include/linux/audit.h:441:21: warning: dereferencing ‘void *’ pointer
include/linux/audit.h:441:21: error: void value not ignored as it ought to be

Thanks,
//richard