Re: [patch 1/4] mm: Introduce check_data_rlimit helper, v2

From: Serge E. Hallyn
Date: Mon Aug 04 2014 - 16:25:48 EST


Quoting Cyrill Gorcunov (gorcunov@xxxxxxxxxx):
> To eliminate code duplication lets introduce check_data_rlimit
> helper which we will use in brk() and prctl() syscalls.
>
> v2 (serge.hallyn@):
> - need to check against RLIM_INFINITY rather than RLIMIT_DATA
>
> Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Andrew Vagin <avagin@xxxxxxxxxx>
> Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>

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

> Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
> Cc: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
> Cc: Julien Tinnes <jln@xxxxxxxxxx>
> ---
> include/linux/mm.h | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> Index: linux-2.6.git/include/linux/mm.h
> ===================================================================
> --- linux-2.6.git.orig/include/linux/mm.h
> +++ linux-2.6.git/include/linux/mm.h
> @@ -18,6 +18,7 @@
> #include <linux/pfn.h>
> #include <linux/bit_spinlock.h>
> #include <linux/shrinker.h>
> +#include <linux/resource.h>
>
> struct mempolicy;
> struct anon_vma;
> @@ -1780,6 +1781,20 @@ extern struct vm_area_struct *copy_vma(s
> bool *need_rmap_locks);
> extern void exit_mmap(struct mm_struct *);
>
> +static inline int check_data_rlimit(unsigned long rlim,
> + unsigned long new,
> + unsigned long start,
> + unsigned long end_data,
> + unsigned long start_data)
> +{
> + if (rlim < RLIM_INFINITY) {
> + if (((new - start) + (end_data - start_data)) > rlim)
> + return -ENOSPC;
> + }
> +
> + return 0;
> +}
> +
> extern int mm_take_all_locks(struct mm_struct *mm);
> extern void mm_drop_all_locks(struct mm_struct *mm);
>
>
> --
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