bpf: change bpf_probe_write_user to bpf_trace_printk in test_verifier

There are four tests in test_verifier using bpf_probe_write_user
helper. These four tests will emit the following kernel messages
  [   12.974753] test_verifier[220] is installing a program with bpf_probe_write_user
                                    helper that may corrupt user memory!
  [   12.979285] test_verifier[220] is installing a program with bpf_probe_write_user
                                    helper that may corrupt user memory!
  ......

This may confuse certain users. This patch replaces bpf_probe_write_user
with bpf_trace_printk. The test_verifier already uses bpf_trace_printk
earlier in the test and a trace_printk warning message has been printed.
So this patch does not emit any more kernel messages.

Fixes: b6ff63911232 ("bpf: fix and add test cases for ARG_CONST_SIZE_OR_ZERO semantics change")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index bf092b83e45382e063fbfadf5ae5c84613fdd9f5..2a5267bef1607c18b3212d95e2db3f56f7801a61 100644 (file)
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -4377,11 +4377,10 @@ static struct bpf_test tests[] = {
                        BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
                        BPF_LD_MAP_FD(BPF_REG_1, 0),
                        BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
-                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
-                       BPF_MOV64_IMM(BPF_REG_1, 0),
-                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
-                       BPF_MOV64_IMM(BPF_REG_3, 0),
-                       BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_trace_printk),
                        BPF_EXIT_INSN(),
                },
                .fixup_map2 = { 3 },
@@ -4481,14 +4480,12 @@ static struct bpf_test tests[] = {
                        BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
                        BPF_LD_MAP_FD(BPF_REG_1, 0),
                        BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
-                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_1,
                                offsetof(struct test_val, foo)),
-                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
-                       BPF_MOV64_IMM(BPF_REG_1, 0),
-                       BPF_MOV64_IMM(BPF_REG_3, 0),
-                       BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_trace_printk),
                        BPF_EXIT_INSN(),
                },
                .fixup_map2 = { 3 },
@@ -4618,18 +4615,16 @@ static struct bpf_test tests[] = {
                        BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
                        BPF_LD_MAP_FD(BPF_REG_1, 0),
                        BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
-                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5),
                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
                        BPF_MOV64_IMM(BPF_REG_3, 0),
                        BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_3),
-                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
-                       BPF_MOV64_IMM(BPF_REG_1, 0),
-                       BPF_MOV64_IMM(BPF_REG_3, 0),
-                       BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_trace_printk),
                        BPF_EXIT_INSN(),
                },
                .fixup_map2 = { 3 },
-               .errstr = "R2 min value is outside of the array range",
+               .errstr = "R1 min value is outside of the array range",
                .result = REJECT,
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
        },
@@ -4760,20 +4755,18 @@ static struct bpf_test tests[] = {
                        BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
                        BPF_LD_MAP_FD(BPF_REG_1, 0),
                        BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
-                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
                        BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_0, 0),
                        BPF_JMP_IMM(BPF_JGT, BPF_REG_3,
-                               offsetof(struct test_val, foo), 4),
+                               offsetof(struct test_val, foo), 3),
                        BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_3),
-                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
-                       BPF_MOV64_IMM(BPF_REG_1, 0),
-                       BPF_MOV64_IMM(BPF_REG_3, 0),
-                       BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_trace_printk),
                        BPF_EXIT_INSN(),
                },
                .fixup_map2 = { 3 },
-               .errstr = "R2 min value is outside of the array range",
+               .errstr = "R1 min value is outside of the array range",
                .result = REJECT,
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
        },