bpf: fix and add test cases for ARG_CONST_SIZE_OR_ZERO semantics change

Fix a few test cases to allow non-NULL map/packet/stack pointer
with size = 0. Change a few tests using bpf_probe_read to use
bpf_probe_write_user so ARG_CONST_SIZE arg can still be properly
tested. One existing test case already covers size = 0 with non-NULL
packet pointer, so add additional tests so all cases of
size = 0 and 0 <= size <= legal_upper_bound with non-NULL
map/packet/stack pointer are covered.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index bb3c4ad..bf092b8 100644 (file)
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -3579,7 +3579,7 @@ static struct bpf_test tests[] = {
                .prog_type = BPF_PROG_TYPE_SCHED_CLS,
        },
        {
-               "helper access to packet: test19, cls helper fail range zero",
+               "helper access to packet: test19, cls helper range zero",
                .insns = {
                        BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
                                    offsetof(struct __sk_buff, data)),
@@ -3599,8 +3599,7 @@ static struct bpf_test tests[] = {
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
-               .result = REJECT,
-               .errstr = "invalid access to packet",
+               .result = ACCEPT,
                .prog_type = BPF_PROG_TYPE_SCHED_CLS,
        },
        {
@@ -4379,10 +4378,10 @@ static struct bpf_test tests[] = {
                        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_REG(BPF_REG_1, BPF_REG_0),
-                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       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_read),
+                       BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
                        BPF_EXIT_INSN(),
                },
                .fixup_map2 = { 3 },
@@ -4486,9 +4485,10 @@ static struct bpf_test tests[] = {
                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_1,
                                offsetof(struct test_val, foo)),
-                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       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_read),
+                       BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
                        BPF_EXIT_INSN(),
                },
                .fixup_map2 = { 3 },
@@ -4622,13 +4622,14 @@ static struct bpf_test tests[] = {
                        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_IMM(BPF_REG_2, 0),
+                       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_read),
+                       BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
                        BPF_EXIT_INSN(),
                },
                .fixup_map2 = { 3 },
-               .errstr = "R1 min value is outside of the array range",
+               .errstr = "R2 min value is outside of the array range",
                .result = REJECT,
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
        },
@@ -4765,13 +4766,14 @@ static struct bpf_test tests[] = {
                        BPF_JMP_IMM(BPF_JGT, BPF_REG_3,
                                offsetof(struct test_val, foo), 4),
                        BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_3),
-                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       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_read),
+                       BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
                        BPF_EXIT_INSN(),
                },
                .fixup_map2 = { 3 },
-               .errstr = "R1 min value is outside of the array range",
+               .errstr = "R2 min value is outside of the array range",
                .result = REJECT,
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
        },
@@ -5350,7 +5352,7 @@ static struct bpf_test tests[] = {
                        BPF_EMIT_CALL(BPF_FUNC_probe_read),
                        BPF_EXIT_INSN(),
                },
-               .errstr = "invalid stack type R1 off=-64 access_size=0",
+               .errstr = "invalid indirect read from stack off -64+0 size 64",
                .result = REJECT,
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
        },
@@ -5505,7 +5507,7 @@ static struct bpf_test tests[] = {
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
-               .errstr = "invalid stack type R1 off=-64 access_size=0",
+               .errstr = "invalid indirect read from stack off -64+0 size 64",
                .result = REJECT,
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
        },
@@ -5668,7 +5670,7 @@ static struct bpf_test tests[] = {
                .prog_type = BPF_PROG_TYPE_SCHED_CLS,
        },
        {
-               "helper access to variable memory: size = 0 not allowed on != NULL",
+               "helper access to variable memory: size = 0 allowed on != NULL stack pointer",
                .insns = {
                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
@@ -5681,8 +5683,99 @@ static struct bpf_test tests[] = {
                        BPF_EMIT_CALL(BPF_FUNC_csum_diff),
                        BPF_EXIT_INSN(),
                },
-               .errstr = "invalid stack type R1 off=-8 access_size=0",
-               .result = REJECT,
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       },
+       {
+               "helper access to variable memory: size = 0 allowed on != NULL map pointer",
+               .insns = {
+                       BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       BPF_LD_MAP_FD(BPF_REG_1, 0),
+                       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+                                    BPF_FUNC_map_lookup_elem),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       BPF_MOV64_IMM(BPF_REG_3, 0),
+                       BPF_MOV64_IMM(BPF_REG_4, 0),
+                       BPF_MOV64_IMM(BPF_REG_5, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_csum_diff),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 3 },
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       },
+       {
+               "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer",
+               .insns = {
+                       BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       BPF_LD_MAP_FD(BPF_REG_1, 0),
+                       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+                                    BPF_FUNC_map_lookup_elem),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 9),
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
+                       BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 7),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+                       BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, 0),
+                       BPF_MOV64_IMM(BPF_REG_3, 0),
+                       BPF_MOV64_IMM(BPF_REG_4, 0),
+                       BPF_MOV64_IMM(BPF_REG_5, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_csum_diff),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 3 },
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       },
+       {
+               "helper access to variable memory: size possible = 0 allowed on != NULL map pointer",
+               .insns = {
+                       BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       BPF_LD_MAP_FD(BPF_REG_1, 0),
+                       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+                                    BPF_FUNC_map_lookup_elem),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
+                       BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 4),
+                       BPF_MOV64_IMM(BPF_REG_3, 0),
+                       BPF_MOV64_IMM(BPF_REG_4, 0),
+                       BPF_MOV64_IMM(BPF_REG_5, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_csum_diff),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 3 },
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       },
+       {
+               "helper access to variable memory: size possible = 0 allowed on != NULL packet pointer",
+               .insns = {
+                       BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
+                                   offsetof(struct __sk_buff, data)),
+                       BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+                                   offsetof(struct __sk_buff, data_end)),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_6),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
+                       BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 7),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_6, 0),
+                       BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 4),
+                       BPF_MOV64_IMM(BPF_REG_3, 0),
+                       BPF_MOV64_IMM(BPF_REG_4, 0),
+                       BPF_MOV64_IMM(BPF_REG_5, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_csum_diff),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
                .prog_type = BPF_PROG_TYPE_SCHED_CLS,
        },
        {