* [PATCH] Bump vm.mmap_min_addr on 64-bit
@ 2019-04-01 5:06 Alexey Dobriyan
2019-04-01 23:05 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Alexey Dobriyan @ 2019-04-01 5:06 UTC (permalink / raw)
To: akpm; +Cc: linux-mm
No self respecting 64-bit program should ever touch that lowly 32-bit
part of address space.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
mm/Kconfig | 3 ++-
security/Kconfig | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -306,7 +306,8 @@ config KSM
config DEFAULT_MMAP_MIN_ADDR
int "Low address space to protect from user allocation"
depends on MMU
- default 4096
+ default 4096 if !64BIT
+ default 4294967296 if 64BIT
help
This is the portion of low virtual memory which should be protected
from userspace allocation. Keeping a user from writing to low pages
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -129,7 +129,8 @@ config LSM_MMAP_MIN_ADDR
int "Low address space for LSM to protect from user allocation"
depends on SECURITY && SECURITY_SELINUX
default 32768 if ARM || (ARM64 && COMPAT)
- default 65536
+ default 65536 if !64BIT
+ default 4294967296 if 64BIT
help
This is the portion of low virtual memory which should be protected
from userspace allocation. Keeping a user from writing to low pages
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Bump vm.mmap_min_addr on 64-bit
2019-04-01 5:06 [PATCH] Bump vm.mmap_min_addr on 64-bit Alexey Dobriyan
@ 2019-04-01 23:05 ` Andrew Morton
2019-04-02 5:57 ` Alexey Dobriyan
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2019-04-01 23:05 UTC (permalink / raw)
To: Alexey Dobriyan; +Cc: linux-mm
On Mon, 1 Apr 2019 08:06:13 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> No self respecting 64-bit program should ever touch that lowly 32-bit
> part of address space.
>
> ...
>
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -306,7 +306,8 @@ config KSM
> config DEFAULT_MMAP_MIN_ADDR
> int "Low address space to protect from user allocation"
> depends on MMU
> - default 4096
> + default 4096 if !64BIT
> + default 4294967296 if 64BIT
> help
> This is the portion of low virtual memory which should be protected
> from userspace allocation. Keeping a user from writing to low pages
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -129,7 +129,8 @@ config LSM_MMAP_MIN_ADDR
> int "Low address space for LSM to protect from user allocation"
> depends on SECURITY && SECURITY_SELINUX
> default 32768 if ARM || (ARM64 && COMPAT)
> - default 65536
> + default 65536 if !64BIT
> + default 4294967296 if 64BIT
> help
> This is the portion of low virtual memory which should be protected
> from userspace allocation. Keeping a user from writing to low pages
Gee. Do we have any idea what effect this will have upon all userspace
programs, some of which do inexplicably weird things?
What's the benefit?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Bump vm.mmap_min_addr on 64-bit
2019-04-01 23:05 ` Andrew Morton
@ 2019-04-02 5:57 ` Alexey Dobriyan
0 siblings, 0 replies; 3+ messages in thread
From: Alexey Dobriyan @ 2019-04-02 5:57 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-mm
On Mon, Apr 01, 2019 at 04:05:59PM -0700, Andrew Morton wrote:
> On Mon, 1 Apr 2019 08:06:13 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
>
> > No self respecting 64-bit program should ever touch that lowly 32-bit
> > part of address space.
> Gee. Do we have any idea what effect this will have upon all userspace
> programs, some of which do inexplicably weird things?
>
> What's the benefit?
Note the date :^)
^ permalink raw reply [flat|nested] 3+ messages in thread
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