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From:   Dominick Grift <dominick.grift@defensec.nl>
To:     Russell Coker <russell@coker.com.au>
Cc:     selinux-refpolicy@vger.kernel.org
Subject: Re: [PATCH] rasdaemon (replacement for mcelog)
References: <YEWNyIsSThUoVAsc@xev> <ypjl7dmija7e.fsf@defensec.nl>
Date:   Mon, 08 Mar 2021 09:59:35 +0100
In-Reply-To: <ypjl7dmija7e.fsf@defensec.nl> (Dominick Grift's message of "Mon,
        08 Mar 2021 09:55:49 +0100")
Message-ID: <ypjl35x6ja14.fsf@defensec.nl>
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Dominick Grift <dominick.grift@defensec.nl> writes:

> Russell Coker <russell@coker.com.au> writes:
>
>> This is policy for rasdaemon, the new replacement for mcelog.  The
>> /dev/mcelog device is now an obsolete kernel feature that can be enabled
>> for backward compatibility and rasdaeon with tracefs is the new way.
>>
>> I've tested this and it seems to work OK, but all my servers are working
>> well so I haven't been able to test the case of actually detecting an
>> error.  It would be good if someone with a known damaged server could give
>> it a go.
>>
>> I think this is ready for merging.
>>
>> Signed-off-by: Russell Coker <russell@coker.com.au>
>>
>> Index: refpolicy-2.20210203/policy/modules/kernel/filesystem.if
>> ===================================================================
>> --- refpolicy-2.20210203.orig/policy/modules/kernel/filesystem.if
>> +++ refpolicy-2.20210203/policy/modules/kernel/filesystem.if
>> @@ -5302,6 +5302,25 @@ interface(`fs_getattr_tracefs_files',`
>>  
>>  ########################################
>>  ## <summary>
>> +##	Read/write trace filesystem files
>> +## </summary>
>> +## <param name="domain">
>> +##      <summary>
>> +##      Domain allowed access.
>> +##      </summary>
>> +## </param>
>> +#
>> +interface(`fs_write_tracefs_files',`
>> +	gen_require(`
>> +		type tracefs_t;
>> +	')
>> +
>> +	allow $1 tracefs_t:dir list_dir_perms;
>> +	allow $1 tracefs_t:file rw_file_perms;
>> +')
>> +
>> +########################################
>> +## <summary>
>>  ##	Mount a XENFS filesystem.
>>  ## </summary>
>>  ## <param name="domain">
>> Index: refpolicy-2.20210203/policy/modules/services/rasdaemon.fc
>> ===================================================================
>> --- /dev/null
>> +++ refpolicy-2.20210203/policy/modules/services/rasdaemon.fc
>> @@ -0,0 +1,3 @@
>> +/usr/sbin/rasdaemon			--	gen_context(system_u:object_r:rasdaemon_exec_t,s0)
>> +/var/lib/rasdaemon(/.*)?			gen_context(system_u:object_r:rasdaemon_var_t,s0)
>> +
>> Index: refpolicy-2.20210203/policy/modules/services/rasdaemon.if
>> ===================================================================
>> --- /dev/null
>> +++ refpolicy-2.20210203/policy/modules/services/rasdaemon.if
>> @@ -0,0 +1 @@
>> +## <summary></summary>
>> Index: refpolicy-2.20210203/policy/modules/services/rasdaemon.te
>> ===================================================================
>> --- /dev/null
>> +++ refpolicy-2.20210203/policy/modules/services/rasdaemon.te
>> @@ -0,0 +1,49 @@
>> +policy_module(rasdaemon, 1.0.0)
>> +
>> +# rasdaemon is a RAS (Reliability, Availability and Serviceability) logging
>> +# tool.  It currently records memory errors, using the EDAC tracing events.
>> +# EDAC are drivers in the Linux kernel that handle detection of ECC errors
>> +# from memory controllers for most chipsets on x86 and ARM architectures.
>> +#
>> +# https://git.infradead.org/users/mchehab/rasdaemon.git
>
> Please use the <summary></summary> for description. We have an api
> browser (make doc) and the description should end up there as well.
>
> <summary>Reliability, Availability and Serviceability (RAS) logging tool.</summary>
>
> I would omit the url because those are often subject to change anyway.
>
>> +
>> +########################################
>> +#
>> +# Declarations
>> +#
>> +
>> +type rasdaemon_t;
>> +type rasdaemon_exec_t;
>> +init_daemon_domain(rasdaemon_t, rasdaemon_exec_t)
>> +
>> +type rasdaemon_var_t;
>> +files_type(rasdaemon_var_t)
>
> Someone should at some point maybe consider creating a files_state_file()
> for /var/lib so that we can differentiate there
>
>> +
>> +########################################
>> +#
>> +# Local policy
>> +#
>> +
>> +allow rasdaemon_t self:unix_dgram_socket create_socket_perms;
>
> redundant: implied with logging_send_syslog_msg()
>
>> +
>> +# confidentiality for tracefs and integrity for debugfs
>> +allow rasdaemon_t self:lockdown { confidentiality integrity };
>> +
>> +allow rasdaemon_t rasdaemon_var_t:dir manage_dir_perms;
>> +allow rasdaemon_t rasdaemon_var_t:file manage_file_perms;
>> +
>> +kernel_read_debugfs(rasdaemon_t)
>> +kernel_read_system_state(rasdaemon_t)
>> +kernel_read_vm_overcommit_sysctl(rasdaemon_t)
>> +kernel_search_fs_sysctls(rasdaemon_t)
>> +
>> +dev_list_sysfs(rasdaemon_t)
>> +dev_read_urand(rasdaemon_t)
>> +
>> +files_read_etc_symlinks(rasdaemon_t)

Redundant: implied with miscfiles_read_localization()

>> +files_search_var_lib(rasdaemon_t)
>> +fs_write_tracefs_files(rasdaemon_t)
>> +
>> +logging_send_syslog_msg(rasdaemon_t)
>> +miscfiles_read_localization(rasdaemon_t)
>> +
>>

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Dominick Grift