* [PATCH bpf v3 2/2] bpf/selftests: test that kernel rejects a TCP CC with an invalid license
2021-03-26 10:03 [PATCH bpf v3 1/2] bpf: enforce that struct_ops programs be GPL-only Toke Høiland-Jørgensen
@ 2021-03-26 10:03 ` Toke Høiland-Jørgensen
2021-03-26 17:00 ` [PATCH bpf v3 1/2] bpf: enforce that struct_ops programs be GPL-only patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: Toke Høiland-Jørgensen @ 2021-03-26 10:03 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann
Cc: Toke Høiland-Jørgensen, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, Stanislav Fomichev, David S. Miller,
Jesper Dangaard Brouer, Andrea Arcangeli, Clark Williams, bpf,
netdev
This adds a selftest to check that the verifier rejects a TCP CC struct_ops
with a non-GPL license.
v3:
- Rename prog to bpf_tcp_nogpl
- Use ASSERT macros instead of CHECK
- Skip unneeded initialisation, unconditionally close skeleton
v2:
- Use a minimal struct_ops BPF program instead of rewriting bpf_dctcp's
license in memory.
- Check for the verifier reject message instead of just the return code.
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
.../selftests/bpf/prog_tests/bpf_tcp_ca.c | 44 +++++++++++++++++++
.../selftests/bpf/progs/bpf_tcp_nogpl.c | 19 ++++++++
2 files changed, 63 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/bpf_tcp_nogpl.c
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
index 37c5494a0381..e25917f04602 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
@@ -6,6 +6,7 @@
#include <test_progs.h>
#include "bpf_dctcp.skel.h"
#include "bpf_cubic.skel.h"
+#include "bpf_tcp_nogpl.skel.h"
#define min(a, b) ((a) < (b) ? (a) : (b))
@@ -227,10 +228,53 @@ static void test_dctcp(void)
bpf_dctcp__destroy(dctcp_skel);
}
+static char *err_str;
+static bool found;
+
+static int libbpf_debug_print(enum libbpf_print_level level,
+ const char *format, va_list args)
+{
+ char *log_buf;
+
+ if (level != LIBBPF_WARN ||
+ strcmp(format, "libbpf: \n%s\n")) {
+ vprintf(format, args);
+ return 0;
+ }
+
+ log_buf = va_arg(args, char *);
+ if (!log_buf)
+ goto out;
+ if (err_str && strstr(log_buf, err_str) != NULL)
+ found = true;
+out:
+ printf(format, log_buf);
+ return 0;
+}
+
+static void test_invalid_license(void)
+{
+ libbpf_print_fn_t old_print_fn;
+ struct bpf_tcp_nogpl *skel;
+
+ err_str = "struct ops programs must have a GPL compatible license";
+ found = false;
+ old_print_fn = libbpf_set_print(libbpf_debug_print);
+
+ skel = bpf_tcp_nogpl__open_and_load();
+ ASSERT_NULL(skel, "bpf_tcp_nogpl");
+ ASSERT_EQ(found, true, "expected_err_msg");
+
+ bpf_tcp_nogpl__destroy(skel);
+ libbpf_set_print(old_print_fn);
+}
+
void test_bpf_tcp_ca(void)
{
if (test__start_subtest("dctcp"))
test_dctcp();
if (test__start_subtest("cubic"))
test_cubic();
+ if (test__start_subtest("invalid_license"))
+ test_invalid_license();
}
diff --git a/tools/testing/selftests/bpf/progs/bpf_tcp_nogpl.c b/tools/testing/selftests/bpf/progs/bpf_tcp_nogpl.c
new file mode 100644
index 000000000000..2ecd833dcd41
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_tcp_nogpl.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <linux/types.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_tcp_helpers.h"
+
+char _license[] SEC("license") = "X";
+
+void BPF_STRUCT_OPS(nogpltcp_init, struct sock *sk)
+{
+}
+
+SEC(".struct_ops")
+struct tcp_congestion_ops bpf_nogpltcp = {
+ .init = (void *)nogpltcp_init,
+ .name = "bpf_nogpltcp",
+};
--
2.31.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH bpf v3 1/2] bpf: enforce that struct_ops programs be GPL-only
2021-03-26 10:03 [PATCH bpf v3 1/2] bpf: enforce that struct_ops programs be GPL-only Toke Høiland-Jørgensen
2021-03-26 10:03 ` [PATCH bpf v3 2/2] bpf/selftests: test that kernel rejects a TCP CC with an invalid license Toke Høiland-Jørgensen
@ 2021-03-26 17:00 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-03-26 17:00 UTC (permalink / raw)
To: =?utf-8?b?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2VuIDx0b2tlQHJlZGhhdC5jb20+?=
Cc: ast, daniel, andrii, kafai, songliubraving, yhs, john.fastabend,
kpsingh, sdf, davem, brouer, aarcange, williams, bpf, netdev
Hello:
This series was applied to bpf/bpf.git (refs/heads/master):
On Fri, 26 Mar 2021 11:03:13 +0100 you wrote:
> With the introduction of the struct_ops program type, it became possible to
> implement kernel functionality in BPF, making it viable to use BPF in place
> of a regular kernel module for these particular operations.
>
> Thus far, the only user of this mechanism is for implementing TCP
> congestion control algorithms. These are clearly marked as GPL-only when
> implemented as modules (as seen by the use of EXPORT_SYMBOL_GPL for
> tcp_register_congestion_control()), so it seems like an oversight that this
> was not carried over to BPF implementations. Since this is the only user
> of the struct_ops mechanism, just enforcing GPL-only for the struct_ops
> program type seems like the simplest way to fix this.
>
> [...]
Here is the summary with links:
- [bpf,v3,1/2] bpf: enforce that struct_ops programs be GPL-only
https://git.kernel.org/bpf/bpf/c/12aa8a9467b3
- [bpf,v3,2/2] bpf/selftests: test that kernel rejects a TCP CC with an invalid license
https://git.kernel.org/bpf/bpf/c/d8e8052e42d0
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 3+ messages in thread