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

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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: 0365351524 ("net: Allow iterating sockmap and sockhash")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-5-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Hou Tao 2022-08-10 16:05:33 +08:00 committed by Alexei Starovoitov
parent 3c5f6e698b
commit f0d2b2716d
1 changed files with 19 additions and 1 deletions
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20
net/core/sock_map.c
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@ -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),
};
@ -1369,18 +1378,27 @@ static const struct seq_operations sock_hash_seq_ops = {
};
static int sock_hash_init_seq_private(void *priv_data,
struct bpf_iter_aux_info *aux)
struct bpf_iter_aux_info *aux)
{
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),
};