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Message-Id: <20220204005519.60361-3-mcroce@linux.microsoft.com>
Date: Fri, 4 Feb 2022 01:55:19 +0100
From: Matteo Croce <mcroce@...ux.microsoft.com>
To: Alexei Starovoitov <alexei.starovoitov@...il.com>,
bpf@...r.kernel.org
Cc: Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>,
linux-kernel@...r.kernel.org
Subject: [PATCH bpf-next v3 2/2] selftests/bpf: test maximum recursion depth for bpf_core_types_are_compat()
From: Matteo Croce <mcroce@...rosoft.com>
bpf_core_types_are_compat() was limited to 2 recursion levels, which are
enough to parse a function prototype.
Add a test which checks the existence of a function prototype, so to
test the bpf_core_types_are_compat() code path.
The test for the recursion limit being hit is done in a separate object,
because the kernel failure makes the whole load to fail.
Sample run log with extra prints:
[ 5689.913751] bpf_core_apply_relo_insn:1200 cands->len: 2
[ 5689.913902] bpf_core_types_are_compat:6896: ret: 1
[ 5689.913994] bpf_core_types_are_compat:6896: ret: 0
[ 5689.914025] bpf_core_apply_relo_insn:1200 cands->len: 2
[ 5689.914141] bpf_core_types_are_compat:6896: ret: 0
[ 5689.914246] bpf_core_types_are_compat:6896: ret: 0
test_core_kern_lskel:PASS:open_and_load 0 nsec
test_core_kern_lskel:PASS:attach(core_relo_proto) 0 nsec
test_core_kern_lskel:PASS:bpf_core_type_exists 0 nsec
test_core_kern_lskel:PASS:!bpf_core_type_exists 0 nsec
#41 core_kern_lskel:OK
[ 5689.915267] bpf_core_apply_relo_insn:1200 cands->len: 2
[ 5689.915399] bpf_core_types_are_compat:6896: ret: 0
[ 5689.915504] bpf_core_types_are_compat:6896: ret: -22
test_core_kern_overflow_lskel:PASS:open_and_load 0 nsec
#42 core_kern_overflow_lskel:OK
Summary: 2/0 PASSED, 0 SKIPPED, 0 FAILED
Successfully unloaded bpf_testmod.ko.
Signed-off-by: Matteo Croce <mcroce@...rosoft.com>
---
tools/testing/selftests/bpf/Makefile | 2 +-
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 5 +++++
.../selftests/bpf/prog_tests/core_kern.c | 15 ++++++++++++-
.../bpf/prog_tests/core_kern_overflow.c | 13 ++++++++++++
tools/testing/selftests/bpf/progs/core_kern.c | 14 +++++++++++++
.../selftests/bpf/progs/core_kern_overflow.c | 21 +++++++++++++++++++
6 files changed, 68 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/core_kern_overflow.c
create mode 100644 tools/testing/selftests/bpf/progs/core_kern_overflow.c
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 945f92d71db3..91ea729990da 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -330,7 +330,7 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h \
LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \
test_ringbuf.c atomics.c trace_printk.c trace_vprintk.c \
- map_ptr_kern.c core_kern.c
+ map_ptr_kern.c core_kern.c core_kern_overflow.c
# Generate both light skeleton and libbpf skeleton for these
LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test_subprog.c
SKEL_BLACKLIST += $$(LSKELS)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 595d32ab285a..e5ba8d8a17da 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -13,6 +13,11 @@
#define CREATE_TRACE_POINTS
#include "bpf_testmod-events.h"
+typedef int (*func_proto_typedef___match)(long);
+typedef int (*func_proto_typedef___overflow)(func_proto_typedef___match);
+func_proto_typedef___match funcp = NULL;
+func_proto_typedef___overflow funcp_of = NULL;
+
DEFINE_PER_CPU(int, bpf_testmod_ksym_percpu) = 123;
noinline void
diff --git a/tools/testing/selftests/bpf/prog_tests/core_kern.c b/tools/testing/selftests/bpf/prog_tests/core_kern.c
index 561c5185d886..91493f5836ff 100644
--- a/tools/testing/selftests/bpf/prog_tests/core_kern.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_kern.c
@@ -7,8 +7,21 @@
void test_core_kern_lskel(void)
{
struct core_kern_lskel *skel;
+ int link_fd;
skel = core_kern_lskel__open_and_load();
- ASSERT_OK_PTR(skel, "open_and_load");
+ if (!ASSERT_OK_PTR(skel, "open_and_load"))
+ return;
+
+ link_fd = core_kern_lskel__core_relo_proto__attach(skel);
+ if (!ASSERT_GT(link_fd, 0, "attach(core_relo_proto)"))
+ goto cleanup;
+
+ /* trigger tracepoints */
+ usleep(1);
+ ASSERT_TRUE(skel->bss->proto_out[0], "bpf_core_type_exists");
+ ASSERT_FALSE(skel->bss->proto_out[1], "!bpf_core_type_exists");
+
+cleanup:
core_kern_lskel__destroy(skel);
}
diff --git a/tools/testing/selftests/bpf/prog_tests/core_kern_overflow.c b/tools/testing/selftests/bpf/prog_tests/core_kern_overflow.c
new file mode 100644
index 000000000000..04cc145bc26a
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/core_kern_overflow.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "test_progs.h"
+#include "core_kern_overflow.lskel.h"
+
+void test_core_kern_overflow_lskel(void)
+{
+ struct core_kern_overflow_lskel *skel;
+
+ skel = core_kern_overflow_lskel__open_and_load();
+ if (!ASSERT_NULL(skel, "open_and_load"))
+ core_kern_overflow_lskel__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/core_kern.c b/tools/testing/selftests/bpf/progs/core_kern.c
index 13499cc15c7d..acabe4cb0480 100644
--- a/tools/testing/selftests/bpf/progs/core_kern.c
+++ b/tools/testing/selftests/bpf/progs/core_kern.c
@@ -101,4 +101,18 @@ int balancer_ingress(struct __sk_buff *ctx)
return 0;
}
+typedef int (*func_proto_typedef___match)(long);
+typedef void (*func_proto_typedef___doesnt_match)(char*);
+
+int proto_out[2];
+
+SEC("raw_tracepoint/sys_enter")
+int core_relo_proto(void *ctx)
+{
+ proto_out[0] = bpf_core_type_exists(func_proto_typedef___match);
+ proto_out[1] = bpf_core_type_exists(func_proto_typedef___doesnt_match);
+
+ return 0;
+}
+
char LICENSE[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/core_kern_overflow.c b/tools/testing/selftests/bpf/progs/core_kern_overflow.c
new file mode 100644
index 000000000000..70417413af55
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/core_kern_overflow.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "vmlinux.h"
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+typedef int (*func_proto_typedef___match)(long);
+typedef int (*func_proto_typedef___overflow)(func_proto_typedef___match);
+
+int proto_out;
+
+SEC("raw_tracepoint/sys_enter")
+int core_relo_proto(void *ctx)
+{
+ proto_out = bpf_core_type_exists(func_proto_typedef___overflow);
+
+ return 0;
+}
+
+char LICENSE[] SEC("license") = "GPL";
--
2.34.1
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