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Diffstat (limited to 'kernel/bpf/syscall.c')
-rw-r--r--kernel/bpf/syscall.c90
1 files changed, 73 insertions, 17 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 637397059f76..2a2efe1bc76c 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -18,6 +18,8 @@
#include <linux/filter.h>
#include <linux/version.h>
+DEFINE_PER_CPU(int, bpf_prog_active);
+
int sysctl_unprivileged_bpf_disabled __read_mostly;
static LIST_HEAD(bpf_map_types);
@@ -46,6 +48,19 @@ void bpf_register_map_type(struct bpf_map_type_list *tl)
list_add(&tl->list_node, &bpf_map_types);
}
+int bpf_map_precharge_memlock(u32 pages)
+{
+ struct user_struct *user = get_current_user();
+ unsigned long memlock_limit, cur;
+
+ memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+ cur = atomic_long_read(&user->locked_vm);
+ free_uid(user);
+ if (cur + pages > memlock_limit)
+ return -EPERM;
+ return 0;
+}
+
static int bpf_map_charge_memlock(struct bpf_map *map)
{
struct user_struct *user = get_current_user();
@@ -151,7 +166,7 @@ int bpf_map_new_fd(struct bpf_map *map)
offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
sizeof(attr->CMD##_LAST_FIELD)) != NULL
-#define BPF_MAP_CREATE_LAST_FIELD max_entries
+#define BPF_MAP_CREATE_LAST_FIELD map_flags
/* called via syscall */
static int map_create(union bpf_attr *attr)
{
@@ -229,6 +244,11 @@ static void __user *u64_to_ptr(__u64 val)
return (void __user *) (unsigned long) val;
}
+int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
+{
+ return -ENOTSUPP;
+}
+
/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value
@@ -239,6 +259,7 @@ static int map_lookup_elem(union bpf_attr *attr)
int ufd = attr->map_fd;
struct bpf_map *map;
void *key, *value, *ptr;
+ u32 value_size;
struct fd f;
int err;
@@ -259,23 +280,37 @@ static int map_lookup_elem(union bpf_attr *attr)
if (copy_from_user(key, ukey, map->key_size) != 0)
goto free_key;
+ if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+ map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
+ value_size = round_up(map->value_size, 8) * num_possible_cpus();
+ else
+ value_size = map->value_size;
+
err = -ENOMEM;
- value = kmalloc(map->value_size, GFP_USER | __GFP_NOWARN);
+ value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
if (!value)
goto free_key;
- rcu_read_lock();
- ptr = map->ops->map_lookup_elem(map, key);
- if (ptr)
- memcpy(value, ptr, map->value_size);
- rcu_read_unlock();
+ if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
+ err = bpf_percpu_hash_copy(map, key, value);
+ } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
+ err = bpf_percpu_array_copy(map, key, value);
+ } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
+ err = bpf_stackmap_copy(map, key, value);
+ } else {
+ rcu_read_lock();
+ ptr = map->ops->map_lookup_elem(map, key);
+ if (ptr)
+ memcpy(value, ptr, value_size);
+ rcu_read_unlock();
+ err = ptr ? 0 : -ENOENT;
+ }
- err = -ENOENT;
- if (!ptr)
+ if (err)
goto free_value;
err = -EFAULT;
- if (copy_to_user(uvalue, value, map->value_size) != 0)
+ if (copy_to_user(uvalue, value, value_size) != 0)
goto free_value;
err = 0;
@@ -298,6 +333,7 @@ static int map_update_elem(union bpf_attr *attr)
int ufd = attr->map_fd;
struct bpf_map *map;
void *key, *value;
+ u32 value_size;
struct fd f;
int err;
@@ -318,21 +354,37 @@ static int map_update_elem(union bpf_attr *attr)
if (copy_from_user(key, ukey, map->key_size) != 0)
goto free_key;
+ if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+ map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
+ value_size = round_up(map->value_size, 8) * num_possible_cpus();
+ else
+ value_size = map->value_size;
+
err = -ENOMEM;
- value = kmalloc(map->value_size, GFP_USER | __GFP_NOWARN);
+ value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
if (!value)
goto free_key;
err = -EFAULT;
- if (copy_from_user(value, uvalue, map->value_size) != 0)
+ if (copy_from_user(value, uvalue, value_size) != 0)
goto free_value;
- /* eBPF program that use maps are running under rcu_read_lock(),
- * therefore all map accessors rely on this fact, so do the same here
+ /* must increment bpf_prog_active to avoid kprobe+bpf triggering from
+ * inside bpf map update or delete otherwise deadlocks are possible
*/
- rcu_read_lock();
- err = map->ops->map_update_elem(map, key, value, attr->flags);
- rcu_read_unlock();
+ preempt_disable();
+ __this_cpu_inc(bpf_prog_active);
+ if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
+ err = bpf_percpu_hash_update(map, key, value, attr->flags);
+ } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
+ err = bpf_percpu_array_update(map, key, value, attr->flags);
+ } else {
+ rcu_read_lock();
+ err = map->ops->map_update_elem(map, key, value, attr->flags);
+ rcu_read_unlock();
+ }
+ __this_cpu_dec(bpf_prog_active);
+ preempt_enable();
free_value:
kfree(value);
@@ -371,9 +423,13 @@ static int map_delete_elem(union bpf_attr *attr)
if (copy_from_user(key, ukey, map->key_size) != 0)
goto free_key;
+ preempt_disable();
+ __this_cpu_inc(bpf_prog_active);
rcu_read_lock();
err = map->ops->map_delete_elem(map, key);
rcu_read_unlock();
+ __this_cpu_dec(bpf_prog_active);
+ preempt_enable();
free_key:
kfree(key);