From: Hou Tao houtao1@huawei.com
commit f0d2b2716d71778d0b0c8eaa433c073287d69d93 upstream.
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: 0365351524d7 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/sock_map.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-)
--- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -789,13 +789,22 @@ static int sock_map_init_seq_private(voi { 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), };
@@ -1376,18 +1385,27 @@ static const struct seq_operations sock_ };
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), };