bpf: change bpf_probe_write_user to bpf_trace_printk in test_verifier

yonghong-song · borkmann · commit f1a8b8e3d98b · 2017-11-21T21:23:05.000+01:00
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: b6ff639 ("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
@@ -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,
 	},
