This ensures that buffers retrieved from dynptr_data are allowed to be passed in to helpers that take mem, like bpf_strncmp
Signed-off-by: Daniel Rosenberg drosen@google.com --- .../testing/selftests/bpf/prog_tests/dynptr.c | 1 + .../selftests/bpf/progs/dynptr_success.c | 21 +++++++++++++++++++ 2 files changed, 22 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c index 13d4b9ab16e7..7cfac53c0d58 100644 --- a/tools/testing/selftests/bpf/prog_tests/dynptr.c +++ b/tools/testing/selftests/bpf/prog_tests/dynptr.c @@ -27,6 +27,7 @@ static struct { {"test_dynptr_is_rdonly", SETUP_SKB_PROG}, {"test_dynptr_clone", SETUP_SKB_PROG}, {"test_dynptr_skb_no_buff", SETUP_SKB_PROG}, + {"test_dynptr_skb_strcmp", SETUP_SKB_PROG}, };
static void verify_success(const char *prog_name, enum test_setup_type setup_type) diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c index d299ef3b4d1f..0c053976f8f9 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_success.c +++ b/tools/testing/selftests/bpf/progs/dynptr_success.c @@ -522,3 +522,24 @@ int test_dynptr_skb_no_buff(struct __sk_buff *skb)
return !!data; } + +SEC("?cgroup_skb/egress") +int test_dynptr_skb_strcmp(struct __sk_buff *skb) +{ + struct bpf_dynptr ptr; + char *data; + + if (bpf_dynptr_from_skb(skb, 0, &ptr)) { + err = 1; + return 1; + } + + /* This may return NULL. SKB may require a buffer */ + data = bpf_dynptr_slice(&ptr, 0, NULL, 10); + if (data) { + bpf_strncmp(data, 10, "foo"); + return 1; + } + + return 1; +}