[refpolicy] [PATCH v2 1/2] Allow all domains to read /proc/sys/vm/overcommit_memory

[cpebenito@tresys.com (Christopher J. PeBenito)]

On 8/2/2014 2:47 PM, Vincent Brillault wrote:
> From: Dan Walsh <dwalsh@redhat.com>
> 
> glibc malloc read this file since commit 9fab36eb
> (https://sourceware.org/git/?p=glibc.git;a=commit;h=9fab36eb)
> 
> Patch adapted from commit 343c0887514718387f36ee8ead2b941ba9bfb894
> on fedora selinux-policy
> 
> Signed-off-by: Vincent Brillault <git@lerya.net>
> ---
>  policy/modules/kernel/domain.te |  4 +++
>  policy/modules/kernel/kernel.if | 57 +++++++++++++++++++++++++++++++++++++++++
>  policy/modules/kernel/kernel.te |  4 +++
>  3 files changed, 65 insertions(+)
> 
> diff --git a/policy/modules/kernel/domain.te b/policy/modules/kernel/domain.te
> index 4af7dbd..b95c75d 100644
> --- a/policy/modules/kernel/domain.te
> +++ b/policy/modules/kernel/domain.te
> @@ -99,6 +99,10 @@ allow domain self:process { fork sigchld };
>  # glibc get_nprocs requires read access to /sys/devices/system/cpu/online
>  dev_read_cpu_online(domain)
>  
> +# glibc malloc requires access to /proc/sys/vm/overcommit_memory
> +# see https://sourceware.org/git/?p=glibc.git;a=commit;h=9fab36eb
> +kernel_read_vm_overcommit_sysctls(domain)

This set of lines should go higher than dev_read_cpu_online().


> +interface(`kernel_read_vm_overcommit_sysctls',`
> +	gen_require(`
> +		type proc_t, sysctl_t, sysctl_vm_overcommit_t;
> +	')
> +
> +	read_files_pattern($1, { proc_t sysctl_t sysctl_vm_overcommit_t }, sysctl_vm_overcommit_t)
> +')
[...]
> +interface(`kernel_rw_vm_overcommit_sysctls',`
> +	gen_require(`
> +		type proc_t, sysctl_t, sysctl_vm_overcommit_t;
> +	')
> +
> +	rw_files_pattern($1 ,{ proc_t sysctl_t sysctl_vm_overcommit_t }, sysctl_vm_overcommit_t)
> +	list_dirs_pattern($1, { proc_t sysctl_t }, sysctl_vm_overcommit_t)
> +')

These two interfaces are overspecified.  sysctl_vm_overcommit_t
shouldn't be included in the second parameter of the patterns
(read_files_pattern and rw_files_pattern) since the type is never used
on a directory.

-- 
Chris PeBenito
Tresys Technology, LLC
www.tresys.com | oss.tresys.com