From: Krzesimir Nowak <krzesimir@kinvolk.io>
To: netdev@vger.kernel.org
Cc: "Alban Crequy" <alban@kinvolk.io>,
"Iago López Galeiras" <iago@kinvolk.io>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
"Krzesimir Nowak" <krzesimir@kinvolk.io>
Subject: [bpf-next v2 10/10] selftests/bpf: Test correctness of narrow 32bit read on 64bit field
Date: Tue, 25 Jun 2019 21:42:15 +0200 [thread overview]
Message-ID: <20190625194215.14927-11-krzesimir@kinvolk.io> (raw)
In-Reply-To: <20190625194215.14927-1-krzesimir@kinvolk.io>
Test the correctness of the 32bit narrow reads by reading both halves
of the 64 bit field and doing a binary or on them to see if we get the
original value.
It succeeds as it should, but with the commit e2f7fc0ac695 ("bpf: fix
undefined behavior in narrow load handling") reverted, the test fails
with a following message:
> $ sudo ./test_verifier
> ...
> #967/p 32bit loads of a 64bit field (both least and most significant words) FAIL retval -1985229329 != 0
> verification time 17 usec
> stack depth 0
> processed 8 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
> ...
> Summary: 1519 PASSED, 0 SKIPPED, 1 FAILED
Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>
---
tools/testing/selftests/bpf/test_verifier.c | 19 ++++++++++++++++++
.../testing/selftests/bpf/verifier/var_off.c | 20 +++++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 6fa962014b64..444c1ea1e326 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -24,6 +24,7 @@
#include <sys/capability.h>
+#include <linux/compiler.h>
#include <linux/unistd.h>
#include <linux/filter.h>
#include <linux/bpf_perf_event.h>
@@ -341,6 +342,24 @@ static void bpf_fill_perf_event_test_run_check(struct bpf_test *self)
self->fill_insns = NULL;
}
+static void bpf_fill_32bit_loads(struct bpf_test *self)
+{
+ compiletime_assert(
+ sizeof(struct bpf_perf_event_data) <= TEST_CTX_LEN,
+ "buffer for ctx is too short to fit struct bpf_perf_event_data");
+ compiletime_assert(
+ sizeof(struct bpf_perf_event_value) <= TEST_DATA_LEN,
+ "buffer for data is too short to fit struct bpf_perf_event_value");
+
+ struct bpf_perf_event_data ctx = {
+ .sample_period = 0x0123456789abcdef,
+ };
+
+ memcpy(self->ctx, &ctx, sizeof(ctx));
+ free(self->fill_insns);
+ self->fill_insns = NULL;
+}
+
/* BPF_SK_LOOKUP contains 13 instructions, if you need to fix up maps */
#define BPF_SK_LOOKUP(func) \
/* struct bpf_sock_tuple tuple = {} */ \
diff --git a/tools/testing/selftests/bpf/verifier/var_off.c b/tools/testing/selftests/bpf/verifier/var_off.c
index 8504ac937809..14d222f37081 100644
--- a/tools/testing/selftests/bpf/verifier/var_off.c
+++ b/tools/testing/selftests/bpf/verifier/var_off.c
@@ -246,3 +246,23 @@
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_LWT_IN,
},
+{
+ "32bit loads of a 64bit field (both least and most significant words)",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, offsetof(struct bpf_perf_event_data, sample_period)),
+ BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1, offsetof(struct bpf_perf_event_data, sample_period) + 4),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct bpf_perf_event_data, sample_period)),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_5, 32),
+ BPF_ALU64_REG(BPF_OR, BPF_REG_4, BPF_REG_5),
+ BPF_ALU64_REG(BPF_XOR, BPF_REG_4, BPF_REG_6),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_4),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_PERF_EVENT,
+ .ctx = { 0, },
+ .ctx_len = sizeof(struct bpf_perf_event_data),
+ .data = { 0, },
+ .data_len = sizeof(struct bpf_perf_event_value),
+ .fill_helper = bpf_fill_32bit_loads,
+},
--
2.20.1
prev parent reply other threads:[~2019-06-25 19:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 19:42 [bpf-next v2 00/10] Test the 32bit narrow reads Krzesimir Nowak
2019-06-25 19:42 ` [bpf-next v2 01/10] selftests/bpf: Print a message when tester could not run a program Krzesimir Nowak
2019-06-25 19:42 ` [bpf-next v2 02/10] selftests/bpf: Avoid a clobbering of errno Krzesimir Nowak
2019-06-25 19:42 ` [bpf-next v2 03/10] selftests/bpf: Avoid another case of errno clobbering Krzesimir Nowak
2019-06-25 20:08 ` Stanislav Fomichev
2019-06-25 19:42 ` [bpf-next v2 04/10] selftests/bpf: Use bpf_prog_test_run_xattr Krzesimir Nowak
2019-06-25 19:42 ` [bpf-next v2 05/10] selftests/bpf: Allow passing more information to BPF prog test run Krzesimir Nowak
2019-06-25 19:42 ` [bpf-next v2 06/10] tools headers: Adopt compiletime_assert from kernel sources Krzesimir Nowak
2019-06-25 19:42 ` [bpf-next v2 07/10] tools headers: sync struct bpf_perf_event_data Krzesimir Nowak
2019-06-25 19:42 ` [bpf-next v2 08/10] bpf: Implement bpf_prog_test_run for perf event programs Krzesimir Nowak
2019-06-25 20:12 ` Stanislav Fomichev
2019-06-26 9:10 ` Krzesimir Nowak
2019-06-26 16:12 ` Stanislav Fomichev
2019-07-08 16:51 ` Krzesimir Nowak
2019-06-25 19:42 ` [bpf-next v2 09/10] selftests/bpf: Add tests for bpf_prog_test_run for perf events progs Krzesimir Nowak
2019-06-25 19:42 ` Krzesimir Nowak [this message]
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