From: Hou Tao houtao1@huawei.com
commit 3c5f6e698b5c538bbb23cd453b22e1e4922cffd8 upstream.
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: 5ce6e77c7edf ("bpf: Implement bpf iterator for sock local storage map") Signed-off-by: Hou Tao houtao1@huawei.com Acked-by: Yonghong Song yhs@fb.com Acked-by: Martin KaFai Lau kafai@fb.com Link: https://lore.kernel.org/r/20220810080538.1845898-4-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/bpf_sk_storage.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -794,10 +794,18 @@ static int bpf_iter_init_sk_storage_map( { 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) @@ -843,7 +851,7 @@ static const struct seq_operations bpf_s 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), };