Commit f0d2b271 authored by Hou Tao's avatar Hou Tao Committed by Alexei Starovoitov
Browse files

bpf: Acquire map uref in .init_seq_private for sock{map,hash} iterator 



sock_map_iter_attach_target() 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 sock_map_iter_detach_target() as part of
bpf_link_release(), or could be released in bpf_map_put_with_uref() as
part of bpf_map_release().

Fixing it by acquiring an extra map uref in .init_seq_private and
releasing it in .fini_seq_private.

Fixes: 03653515 ("net: Allow iterating sockmap and sockhash")
Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-5-houtao@huaweicloud.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 3c5f6e69

net/core/sock_map.c

+19 −1
Original line number Diff line number Diff line
@@ -783,13 +783,22 @@ static int sock_map_init_seq_private(void *priv_data, 
{

	struct sock_map_seq_info *info = priv_data;



	bpf_map_inc_with_uref(aux->map);

	info->map = aux->map;

	return 0;

}



static void sock_map_fini_seq_private(void *priv_data)

{

	struct sock_map_seq_info *info = priv_data;



	bpf_map_put_with_uref(info->map);

}



static const struct bpf_iter_seq_info sock_map_iter_seq_info = {

	.seq_ops		= &sock_map_seq_ops,

	.init_seq_private	= sock_map_init_seq_private,

	.fini_seq_private	= sock_map_fini_seq_private,

	.seq_priv_size		= sizeof(struct sock_map_seq_info),

};
@@ -1373,14 +1382,23 @@ static int sock_hash_init_seq_private(void *priv_data, 
{

	struct sock_hash_seq_info *info = priv_data;



	bpf_map_inc_with_uref(aux->map);

	info->map = aux->map;

	info->htab = container_of(aux->map, struct bpf_shtab, map);

	return 0;

}



static void sock_hash_fini_seq_private(void *priv_data)

{

	struct sock_hash_seq_info *info = priv_data;



	bpf_map_put_with_uref(info->map);

}



static const struct bpf_iter_seq_info sock_hash_iter_seq_info = {

	.seq_ops		= &sock_hash_seq_ops,

	.init_seq_private	= sock_hash_init_seq_private,

	.fini_seq_private	= sock_hash_fini_seq_private,

	.seq_priv_size		= sizeof(struct sock_hash_seq_info),

};