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authorDaniel Borkmann <daniel@iogearbox.net>2019-12-17 13:28:16 +0100
committerAlexei Starovoitov <ast@kernel.org>2019-12-17 08:58:02 -0800
commite47304232b373362228bf233f17bd12b11c9aafc (patch)
treeb08fea42367c08dec3f9190689f0a6c84dd84068 /kernel
parenta2ea07465c8d7984cc6b8b1f0b3324f9b138094a (diff)
downloadlinux-e47304232b373362228bf233f17bd12b11c9aafc.tar.bz2
bpf: Fix cgroup local storage prog tracking
Recently noticed that we're tracking programs related to local storage maps through their prog pointer. This is a wrong assumption since the prog pointer can still change throughout the verification process, for example, whenever bpf_patch_insn_single() is called. Therefore, the prog pointer that was assigned via bpf_cgroup_storage_assign() is not guaranteed to be the same as we pass in bpf_cgroup_storage_release() and the map would therefore remain in busy state forever. Fix this by using the prog's aux pointer which is stable throughout verification and beyond. Fixes: de9cbbaadba5 ("bpf: introduce cgroup storage maps") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/1471c69eca3022218666f909bc927a92388fd09e.1576580332.git.daniel@iogearbox.net
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/core.c3
-rw-r--r--kernel/bpf/local_storage.c24
-rw-r--r--kernel/bpf/verifier.c2
3 files changed, 14 insertions, 15 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 6231858df723..af6b738cf435 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2043,8 +2043,7 @@ static void bpf_free_cgroup_storage(struct bpf_prog_aux *aux)
for_each_cgroup_storage_type(stype) {
if (!aux->cgroup_storage[stype])
continue;
- bpf_cgroup_storage_release(aux->prog,
- aux->cgroup_storage[stype]);
+ bpf_cgroup_storage_release(aux, aux->cgroup_storage[stype]);
}
}
diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
index 2ba750725cb2..6bf605dd4b94 100644
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -20,7 +20,7 @@ struct bpf_cgroup_storage_map {
struct bpf_map map;
spinlock_t lock;
- struct bpf_prog *prog;
+ struct bpf_prog_aux *aux;
struct rb_root root;
struct list_head list;
};
@@ -420,7 +420,7 @@ const struct bpf_map_ops cgroup_storage_map_ops = {
.map_seq_show_elem = cgroup_storage_seq_show_elem,
};
-int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)
+int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *_map)
{
enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
struct bpf_cgroup_storage_map *map = map_to_storage(_map);
@@ -428,14 +428,14 @@ int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)
spin_lock_bh(&map->lock);
- if (map->prog && map->prog != prog)
+ if (map->aux && map->aux != aux)
goto unlock;
- if (prog->aux->cgroup_storage[stype] &&
- prog->aux->cgroup_storage[stype] != _map)
+ if (aux->cgroup_storage[stype] &&
+ aux->cgroup_storage[stype] != _map)
goto unlock;
- map->prog = prog;
- prog->aux->cgroup_storage[stype] = _map;
+ map->aux = aux;
+ aux->cgroup_storage[stype] = _map;
ret = 0;
unlock:
spin_unlock_bh(&map->lock);
@@ -443,16 +443,16 @@ unlock:
return ret;
}
-void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *_map)
+void bpf_cgroup_storage_release(struct bpf_prog_aux *aux, struct bpf_map *_map)
{
enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
struct bpf_cgroup_storage_map *map = map_to_storage(_map);
spin_lock_bh(&map->lock);
- if (map->prog == prog) {
- WARN_ON(prog->aux->cgroup_storage[stype] != _map);
- map->prog = NULL;
- prog->aux->cgroup_storage[stype] = NULL;
+ if (map->aux == aux) {
+ WARN_ON(aux->cgroup_storage[stype] != _map);
+ map->aux = NULL;
+ aux->cgroup_storage[stype] = NULL;
}
spin_unlock_bh(&map->lock);
}
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index a1acdce77070..6ef71429d997 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -8268,7 +8268,7 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
env->used_maps[env->used_map_cnt++] = map;
if (bpf_map_is_cgroup_storage(map) &&
- bpf_cgroup_storage_assign(env->prog, map)) {
+ bpf_cgroup_storage_assign(env->prog->aux, map)) {
verbose(env, "only one cgroup storage of each type is allowed\n");
fdput(f);
return -EBUSY;