On Wed, Sep 28, 2016 at 12:17 PM, Stephen Smalley <s...@tycho.nsa.gov> wrote:
> On 09/28/2016 12:04 PM, Janis Danisevskis wrote:
>> We use the same lookup function for service contexts
>> that we use for property contexts. However, property
>> contexts are namespace based and only compare the
>> prefix. This may lead to service associations with
>> a wrong label.
>>
>> This patch introduces a stricter lookup function for
>> services contexts. Now the service name must match
>> the key of the service label exactly.
>>
>> Signed-off-by: Janis Danisevskis <jda...@android.com>
>> ---
>> libselinux/include/selinux/label.h | 2 ++
>> libselinux/src/label.c | 1 +
>> libselinux/src/label_android_property.c | 50
>> +++++++++++++++++++++++++++++++++
>> libselinux/src/label_internal.h | 3 ++
>> 4 files changed, 56 insertions(+)
>
> Normally each backend would go into its own file, so service would get
> its own. Alternatively, since we are unlikely to ever support one
> without the other, perhaps label_android_property.c should be renamed to
> label_android.c and contain all of the Android-unique backends.
>
>>
>> diff --git a/libselinux/include/selinux/label.h
>> b/libselinux/include/selinux/label.h
>> index f0b1e10..277287e 100644
>> --- a/libselinux/include/selinux/label.h
>> +++ b/libselinux/include/selinux/label.h
>> @@ -34,6 +34,8 @@ struct selabel_handle;
>> #define SELABEL_CTX_DB 3
>> /* Android property service contexts */
>> #define SELABEL_CTX_ANDROID_PROP 4
>> +/* Android service contexts */
>> +#define SELABEL_CTX_ANDROID_SERVICE 5
>>
>> /*
>> * Available options
>> diff --git a/libselinux/src/label.c b/libselinux/src/label.c
>> index 96a4ff1..eb0e766 100644
>> --- a/libselinux/src/label.c
>> +++ b/libselinux/src/label.c
>> @@ -45,6 +45,7 @@ static selabel_initfunc initfuncs[] = {
>> CONFIG_X_BACKEND(selabel_x_init),
>> CONFIG_DB_BACKEND(selabel_db_init),
>> &selabel_property_init,
>> + &selabel_service_init,
>
> Wondering if we should support selective enablement of the property and
> service backends too, similar to what William introduced for media, x,
> and db so that he could disable them on Android (in our case, so we can
> disable property and service backends on Linux distributions).
I was wondering that too, im for it. If ANDROID_HOST patch is applied, we
should just set the defaults to strip them out and only on ANDROID_HOST=y
add them in.
We'd also need to coordinate with the AOSP patches, but I can
routinely update those
based on whats going on.
>
>> };
>>
>> static void selabel_subs_fini(struct selabel_sub *ptr)
>> diff --git a/libselinux/src/label_android_property.c
>> b/libselinux/src/label_android_property.c
>> index 290b438..69d6afd 100644
>> --- a/libselinux/src/label_android_property.c
>> +++ b/libselinux/src/label_android_property.c
>> @@ -279,6 +279,38 @@ finish:
>> return ret;
>> }
>>
>> +static struct selabel_lookup_rec *service_lookup(struct selabel_handle *rec,
>> + const char *key, int __attribute__((unused)) type)
>> +{
>> + struct saved_data *data = (struct saved_data *)rec->data;
>> + spec_t *spec_arr = data->spec_arr;
>> + unsigned int i;
>> + struct selabel_lookup_rec *ret = NULL;
>> +
>> + if (!data->nspec) {
>> + errno = ENOENT;
>> + goto finish;
>> + }
>> +
>> + for (i = 0; i < data->nspec; i++) {
>> + if (strcmp(spec_arr[i].property_key, key) == 0)
>> + break;
>> + if (strcmp(spec_arr[i].property_key, "*") == 0)
>> + break;
>> + }
>> +
>> + if (i >= data->nspec) {
>> + /* No matching specification. */
>> + errno = ENOENT;
>> + goto finish;
>> + }
>> +
>> + ret = &spec_arr[i].lr;
>> +
>> +finish:
>> + return ret;
>> +}
>> +
>> static void stats(struct selabel_handle __attribute__((unused)) *rec)
>> {
>> selinux_log(SELINUX_WARNING, "'stats' functionality not
>> implemented.\n");
>> @@ -302,3 +334,21 @@ int selabel_property_init(struct selabel_handle *rec,
>>
>> return init(rec, opts, nopts);
>> }
>> +
>> +int selabel_service_init(struct selabel_handle *rec,
>> + const struct selinux_opt *opts, unsigned nopts)
>> +{
>> + struct saved_data *data;
>> +
>> + data = (struct saved_data *)malloc(sizeof(*data));
>> + if (!data)
>> + return -1;
>> + memset(data, 0, sizeof(*data));
>> +
>> + rec->data = data;
>> + rec->func_close = &closef;
>> + rec->func_stats = &stats;
>> + rec->func_lookup = &service_lookup;
>> +
>> + return init(rec, opts, nopts);
>> +}
>> diff --git a/libselinux/src/label_internal.h
>> b/libselinux/src/label_internal.h
>> index 7c55531..6a9481a 100644
>> --- a/libselinux/src/label_internal.h
>> +++ b/libselinux/src/label_internal.h
>> @@ -39,6 +39,9 @@ int selabel_db_init(struct selabel_handle *rec,
>> int selabel_property_init(struct selabel_handle *rec,
>> const struct selinux_opt *opts,
>> unsigned nopts) hidden;
>> +int selabel_service_init(struct selabel_handle *rec,
>> + const struct selinux_opt *opts,
>> + unsigned nopts) hidden;
>>
>> /*
>> * Labeling internal structures
>>
>
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--
Respectfully,
William C Roberts
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