Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Feng zhou <zhoufeng.zf@bytedance.com>
To:     martin.lau@linux.dev, ast@kernel.org, daniel@iogearbox.net,
        andrii@kernel.org, song@kernel.org, yhs@fb.com,
        john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
        haoluo@google.com, jolsa@kernel.org, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
        mykolal@fb.com, shuah@kernel.org
Cc:     bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, linux-kselftest@vger.kernel.org,
        yangzhenze@bytedance.com, wangdongdong.6@bytedance.com,
        zhouchengming@bytedance.com, zhoufeng.zf@bytedance.com
Subject: [PATCH v2 2/2] selftests/bpf: Add test to access u32 ptr argument in tracing program
Date:   Fri,  7 Apr 2023 16:46:08 +0800
Message-Id: <20230407084608.62296-3-zhoufeng.zf@bytedance.com>
In-Reply-To: <20230407084608.62296-1-zhoufeng.zf@bytedance.com>
References: <20230407084608.62296-1-zhoufeng.zf@bytedance.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Feng Zhou <zhoufeng.zf@bytedance.com>

Adding verifier test for accessing u32 pointer argument in
tracing programs.

The test program loads 1nd argument of bpf_fentry_test9 function
which is u32 pointer and checks that verifier allows that.

Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
---
 net/bpf/test_run.c                                  |  8 +++++++-
 .../testing/selftests/bpf/verifier/btf_ctx_access.c | 13 +++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index f1652f5fbd2e..68bdfc041a7b 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -541,6 +541,11 @@ int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
 	return (long)arg->a;
 }
 
+__bpf_kfunc u32 bpf_fentry_test9(u32 *a)
+{
+	return *a;
+}
+
 __bpf_kfunc int bpf_modify_return_test(int a, int *b)
 {
 	*b += 1;
@@ -855,7 +860,8 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
 		    bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
 		    bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
 		    bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
-		    bpf_fentry_test8(&arg) != 0)
+		    bpf_fentry_test8(&arg) != 0 ||
+		    bpf_fentry_test9(&retval) != 0)
 			goto out;
 		break;
 	case BPF_MODIFY_RETURN:
diff --git a/tools/testing/selftests/bpf/verifier/btf_ctx_access.c b/tools/testing/selftests/bpf/verifier/btf_ctx_access.c
index 6340db6b46dc..0484d3de040d 100644
--- a/tools/testing/selftests/bpf/verifier/btf_ctx_access.c
+++ b/tools/testing/selftests/bpf/verifier/btf_ctx_access.c
@@ -10,3 +10,16 @@
 	.expected_attach_type = BPF_TRACE_FENTRY,
 	.kfunc = "bpf_modify_return_test",
 },
+
+{
+	"btf_ctx_access u32 pointer accept",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),	/* load 1nd argument value (u32 pointer) */
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_TRACING,
+	.expected_attach_type = BPF_TRACE_FENTRY,
+	.kfunc = "bpf_fentry_test9",
+},
-- 
2.20.1