From 1f443d0f2b5702bad5f03aab544858ddd33999b7 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:35 -0800 Subject: [PATCH] selftests/bpf: Check freeing sk->sk_local_storage with sk_local_storage->smap is NULL This patch tweats the socket_bind bpf prog to test the local_storage->smap == NULL case in the bpf_local_storage_free() code path. The idea is to create the local_storage with the sk_storage_map's selem first. Then add the sk_storage_map2's selem and then delete the earlier sk_storeage_map's selem. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-17-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/progs/local_storage.c | 29 ++++++++++++++++------- 1 file changed, 20 insertions(+), 9 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c index 01c74bc870ae..c8ba7207f5a5 100644 --- a/tools/testing/selftests/bpf/progs/local_storage.c +++ b/tools/testing/selftests/bpf/progs/local_storage.c @@ -108,18 +108,17 @@ int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address, { __u32 pid = bpf_get_current_pid_tgid() >> 32; struct local_storage *storage; - int err; if (pid != monitored_pid) return 0; - storage = bpf_sk_storage_get(&sk_storage_map, sock->sk, 0, - BPF_LOCAL_STORAGE_GET_F_CREATE); + storage = bpf_sk_storage_get(&sk_storage_map, sock->sk, 0, 0); if (!storage) return 0; + sk_storage_result = -1; if (storage->value != DUMMY_STORAGE_VALUE) - sk_storage_result = -1; + return 0; /* This tests that we can associate multiple elements * with the local storage. @@ -129,14 +128,26 @@ int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address, if (!storage) return 0; - err = bpf_sk_storage_delete(&sk_storage_map, sock->sk); - if (err) + if (bpf_sk_storage_delete(&sk_storage_map2, sock->sk)) return 0; - err = bpf_sk_storage_delete(&sk_storage_map2, sock->sk); - if (!err) - sk_storage_result = err; + storage = bpf_sk_storage_get(&sk_storage_map2, sock->sk, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!storage) + return 0; + + if (bpf_sk_storage_delete(&sk_storage_map, sock->sk)) + return 0; + + /* Ensure that the sk_storage_map is disconnected from the storage. + * The storage memory should not be freed back to the + * bpf_mem_alloc of the sk_bpf_storage_map because + * sk_bpf_storage_map may have been gone. + */ + if (!sock->sk->sk_bpf_storage || sock->sk->sk_bpf_storage->smap) + return 0; + sk_storage_result = 0; return 0; } -- 2.11.0