On Thu, Aug 31, 2017 at 2:17 PM, Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 2017-08-31 at 13:56 -0700, Chenbo Feng wrote:
>> From: Chenbo Feng <fengc@xxxxxxxxxx>
>>
>> Introduce a pointer into struct bpf_map to hold the security information
>> about the map. The actual security struct varies based on the security
>> models implemented. Place the LSM hooks before each of the unrestricted
>> eBPF operations, the map_update_elem and map_delete_elem operations are
>> checked by security_map_modify. The map_lookup_elem and map_get_next_key
>> operations are checked by securtiy_map_read.
>>
>> Signed-off-by: Chenbo Feng <fengc@xxxxxxxxxx>
>> ---
>> include/linux/bpf.h | 3 +++
>> kernel/bpf/syscall.c | 28 ++++++++++++++++++++++++++++
>> 2 files changed, 31 insertions(+)
>>
>> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
>> index b69e7a5869ff..ca3e6ff7091d 100644
>> --- a/include/linux/bpf.h
>> +++ b/include/linux/bpf.h
>> @@ -53,6 +53,9 @@ struct bpf_map {
>> struct work_struct work;
>> atomic_t usercnt;
>> struct bpf_map *inner_map_meta;
>> +#ifdef CONFIG_SECURITY
>> + void *security;
>> +#endif
>> };
>>
>> /* function argument constraints */
>> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
>> index 045646da97cc..b15580bcf3b1 100644
>> --- a/kernel/bpf/syscall.c
>> +++ b/kernel/bpf/syscall.c
>> @@ -279,6 +279,10 @@ static int map_create(union bpf_attr *attr)
>> if (err)
>> return -EINVAL;
>>
>> + err = security_map_create();
>> + if (err)
>> + return -EACCES;
>
> Any reason not to just return err?
>
> Mimi
>
Nope... return err might be better. I will fix this in next version.
Thanks
Chenbo
>> +
>> /* find map type and init map: hashtable vs rbtree vs bloom vs ... */
>> map = find_and_alloc_map(attr);
>> if (IS_ERR(map))
>> @@ -291,6 +295,10 @@ static int map_create(union bpf_attr *attr)
>> if (err)
>> goto free_map_nouncharge;
>>
>> + err = security_post_create(map);
>> + if (err < 0)
>> + goto free_map;
>> +
>> err = bpf_map_alloc_id(map);
>> if (err)
>> goto free_map;
>> @@ -410,6 +418,10 @@ static int map_lookup_elem(union bpf_attr *attr)
>> if (IS_ERR(map))
>> return PTR_ERR(map);
>>
>> + err = security_map_read(map);
>> + if (err)
>> + return -EACCES;
>> +
>> key = memdup_user(ukey, map->key_size);
>> if (IS_ERR(key)) {
>> err = PTR_ERR(key);
>> @@ -490,6 +502,10 @@ static int map_update_elem(union bpf_attr *attr)
>> if (IS_ERR(map))
>> return PTR_ERR(map);
>>
>> + err = security_map_modify(map);
>> + if (err)
>> + return -EACCES;
>> +
>> key = memdup_user(ukey, map->key_size);
>> if (IS_ERR(key)) {
>> err = PTR_ERR(key);
>> @@ -573,6 +589,10 @@ static int map_delete_elem(union bpf_attr *attr)
>> if (IS_ERR(map))
>> return PTR_ERR(map);
>>
>> + err = security_map_modify(map);
>> + if (err)
>> + return -EACCES;
>> +
>> key = memdup_user(ukey, map->key_size);
>> if (IS_ERR(key)) {
>> err = PTR_ERR(key);
>> @@ -616,6 +636,10 @@ static int map_get_next_key(union bpf_attr *attr)
>> if (IS_ERR(map))
>> return PTR_ERR(map);
>>
>> + err = security_map_read(map);
>> + if (err)
>> + return -EACCES;
>> +
>> if (ukey) {
>> key = memdup_user(ukey, map->key_size);
>> if (IS_ERR(key)) {
>> @@ -935,6 +959,10 @@ static int bpf_prog_load(union bpf_attr *attr)
>> if (CHECK_ATTR(BPF_PROG_LOAD))
>> return -EINVAL;
>>
>> + err = security_prog_load();
>> + if (err)
>> + return -EACCES;
>> +
>> if (attr->prog_flags & ~BPF_F_STRICT_ALIGNMENT)
>> return -EINVAL;
>>
>
