Commit 3c5f6e69 authored by Hou Tao's avatar Hou Tao Committed by Alexei Starovoitov
Browse files

bpf: Acquire map uref in .init_seq_private for sock local storage map iterator 



bpf_iter_attach_map() acquires a map uref, and the uref may be released
before or in the middle of iterating map elements. For example, the uref
could be released in bpf_iter_detach_map() as part of
bpf_link_release(), or could be released in bpf_map_put_with_uref() as
part of bpf_map_release().

So acquiring an extra map uref in bpf_iter_init_sk_storage_map() and
releasing it in bpf_iter_fini_sk_storage_map().

Fixes: 5ce6e77c ("bpf: Implement bpf iterator for sock local storage map")
Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-4-houtao@huaweicloud.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ef1e93d2

net/core/bpf_sk_storage.c

+9 −1
Original line number Diff line number Diff line
@@ -875,10 +875,18 @@ static int bpf_iter_init_sk_storage_map(void *priv_data, 
{

	struct bpf_iter_seq_sk_storage_map_info *seq_info = priv_data;



	bpf_map_inc_with_uref(aux->map);

	seq_info->map = aux->map;

	return 0;

}



static void bpf_iter_fini_sk_storage_map(void *priv_data)

{

	struct bpf_iter_seq_sk_storage_map_info *seq_info = priv_data;



	bpf_map_put_with_uref(seq_info->map);

}



static int bpf_iter_attach_map(struct bpf_prog *prog,

			       union bpf_iter_link_info *linfo,

			       struct bpf_iter_aux_info *aux)
@@ -924,7 +932,7 @@ static const struct seq_operations bpf_sk_storage_map_seq_ops = { 
static const struct bpf_iter_seq_info iter_seq_info = {

	.seq_ops		= &bpf_sk_storage_map_seq_ops,

	.init_seq_private	= bpf_iter_init_sk_storage_map,

	.fini_seq_private	= NULL,

	.fini_seq_private	= bpf_iter_fini_sk_storage_map,

	.seq_priv_size		= sizeof(struct bpf_iter_seq_sk_storage_map_info),

};