Re: sys_kcmp (was: Re: [PATCH 1/2] ARM: add finit_module syscall to ARM)

[Cyrill Gorcunov <gorcunov@openvz.org>]

On Mon, Sep 24, 2012 at 08:49:42PM +0400, Cyrill Gorcunov wrote:
> > I got past that with:
> > 
> > diff --git a/include/linux/security.h b/include/linux/security.h
> > index 01ef030..14e394d 100644
> > --- a/include/linux/security.h
> > +++ b/include/linux/security.h
> > @@ -118,6 +118,7 @@ void reset_security_ops(void);
> >  extern unsigned long mmap_min_addr;
> >  extern unsigned long dac_mmap_min_addr;
> >  #else
> > +#define mmap_min_addr          0UL
> >  #define dac_mmap_min_addr      0UL
> >  #endif
> > 

I think better to add CONFIG_MMU test here.
---
From: Cyrill Gorcunov <gorcunov@openvz.org>
Subject: prctl: prctl_set_mm -- Don't test for mmap_min_addr on non-MMU config

In case if CONFIG_MMU is not set the @mmap_min_addr
is undefined leading to build error. Thus test for
it iif CONFIG_MMU is present.

Note this code snippet depends on CONFIG_CHECKPOINT_RESTORE=y.

Reported-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
---
 kernel/sys.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6.git/kernel/sys.c
===================================================================
--- linux-2.6.git.orig/kernel/sys.c
+++ linux-2.6.git/kernel/sys.c
@@ -1865,7 +1865,11 @@ static int prctl_set_mm(int opt, unsigne
 	if (opt == PR_SET_MM_EXE_FILE)
 		return prctl_set_mm_exe_file(mm, (unsigned int)addr);
 
+#ifdef CONFIG_MMU
 	if (addr >= TASK_SIZE || addr < mmap_min_addr)
+#else
+	if (addr >= TASK_SIZE)
+#endif
 		return -EINVAL;
 
 	error = -EINVAL;