selftests/bpf: Add write tests for sk local storage map iterator

Add test to validate the overwrite of sock local storage map value in
map iterator and another one to ensure out-of-bound value writing is
rejected.

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/20220810080538.1845898-9-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 20 insertions, 2 deletions

diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_map.c b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_map.c
index 6b70ccaba301..c7b8e006b171 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_map.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_map.c
@@ -16,19 +16,37 @@ struct {
 
 __u32 val_sum = 0;
 __u32 ipv6_sk_count = 0;
+__u32 to_add_val = 0;
 
 SEC("iter/bpf_sk_storage_map")
-int dump_bpf_sk_storage_map(struct bpf_iter__bpf_sk_storage_map *ctx)
+int rw_bpf_sk_storage_map(struct bpf_iter__bpf_sk_storage_map *ctx)
 {
 	struct sock *sk = ctx->sk;
 	__u32 *val = ctx->value;
 
-	if (sk == (void *)0 || val == (void *)0)
+	if (sk == NULL || val == NULL)
 		return 0;
 
 	if (sk->sk_family == AF_INET6)
 		ipv6_sk_count++;
 
 	val_sum += *val;
+
+	*val += to_add_val;
+
+	return 0;
+}
+
+SEC("iter/bpf_sk_storage_map")
+int oob_write_bpf_sk_storage_map(struct bpf_iter__bpf_sk_storage_map *ctx)
+{
+	struct sock *sk = ctx->sk;
+	__u32 *val = ctx->value;
+
+	if (sk == NULL || val == NULL)
+		return 0;
+
+	*(val + 1) = 0xdeadbeef;
+
 	return 0;
 }