Re: [patch 2/4] mm: Use may_adjust_brk helper

["Serge E. Hallyn" <serge@hallyn.com>]

Quoting Cyrill Gorcunov (gorcunov@openvz.org):
> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Andrew Vagin <avagin@openvz.org>
> Cc: Eric W. Biederman <ebiederm@xmission.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Serge Hallyn <serge.hallyn@canonical.com>

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>

> Cc: Pavel Emelyanov <xemul@parallels.com>
> Cc: Vasiliy Kulikov <segoon@openwall.com>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Cc: Michael Kerrisk <mtk.manpages@gmail.com>
> Cc: Julien Tinnes <jln@google.com>
> ---
>  kernel/sys.c |   11 ++++-------
>  mm/mmap.c    |    7 +++----
>  2 files changed, 7 insertions(+), 11 deletions(-)
> 
> Index: linux-2.6.git/kernel/sys.c
> ===================================================================
> --- linux-2.6.git.orig/kernel/sys.c
> +++ linux-2.6.git/kernel/sys.c
> @@ -1693,7 +1693,6 @@ exit:
>  static int prctl_set_mm(int opt, unsigned long addr,
>  			unsigned long arg4, unsigned long arg5)
>  {
> -	unsigned long rlim = rlimit(RLIMIT_DATA);
>  	struct mm_struct *mm = current->mm;
>  	struct vm_area_struct *vma;
>  	int error;
> @@ -1733,9 +1732,8 @@ static int prctl_set_mm(int opt, unsigne
>  		if (addr <= mm->end_data)
>  			goto out;
>  
> -		if (rlim < RLIM_INFINITY &&
> -		    (mm->brk - addr) +
> -		    (mm->end_data - mm->start_data) > rlim)
> +		if (check_data_rlimit(rlimit(RLIMIT_DATA), mm->brk, addr,
> +				      mm->end_data, mm->start_data))
>  			goto out;
>  
>  		mm->start_brk = addr;
> @@ -1745,9 +1743,8 @@ static int prctl_set_mm(int opt, unsigne
>  		if (addr <= mm->end_data)
>  			goto out;
>  
> -		if (rlim < RLIM_INFINITY &&
> -		    (addr - mm->start_brk) +
> -		    (mm->end_data - mm->start_data) > rlim)
> +		if (check_data_rlimit(rlimit(RLIMIT_DATA), addr, mm->start_brk,
> +				      mm->end_data, mm->start_data))
>  			goto out;
>  
>  		mm->brk = addr;
> Index: linux-2.6.git/mm/mmap.c
> ===================================================================
> --- linux-2.6.git.orig/mm/mmap.c
> +++ linux-2.6.git/mm/mmap.c
> @@ -263,7 +263,7 @@ static unsigned long do_brk(unsigned lon
>  
>  SYSCALL_DEFINE1(brk, unsigned long, brk)
>  {
> -	unsigned long rlim, retval;
> +	unsigned long retval;
>  	unsigned long newbrk, oldbrk;
>  	struct mm_struct *mm = current->mm;
>  	unsigned long min_brk;
> @@ -293,9 +293,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
>  	 * segment grow beyond its set limit the in case where the limit is
>  	 * not page aligned -Ram Gupta
>  	 */
> -	rlim = rlimit(RLIMIT_DATA);
> -	if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
> -			(mm->end_data - mm->start_data) > rlim)
> +	if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk,
> +			      mm->end_data, mm->start_data))
>  		goto out;
>  
>  	newbrk = PAGE_ALIGN(brk);
> 
> --
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