[PATCH 2/2] bpf: test_bpf: add tests for upper bits of 32-bit operations
From: Luke Nelson
Date: Thu May 30 2019 - 15:12:01 EST
This commit introduces tests that validate the upper 32 bits
of the result of 32-bit BPF ALU operations.
The existing tests for 32-bit operations do not check the upper 32
bits of results because the exit instruction truncates the result.
These tests perform a 32-bit ALU operation followed by a right shift.
These tests can catch subtle bugs in the extension behavior of JITed
instructions, including several bugs in the RISC-V BPF JIT, fixed in
another patch.
The added tests pass the JIT and interpreter on x86, as well as the
JIT and interpreter of RISC-V once the zero extension bugs were fixed.
Cc: Xi Wang <xi.wang@xxxxxxxxx>
Signed-off-by: Luke Nelson <luke.r.nels@xxxxxxxxx>
---
lib/test_bpf.c | 164 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 164 insertions(+)
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 0845f635f404..4580dc0220f1 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -2461,6 +2461,20 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 1 } },
},
+ {
+ "ALU_ADD_X: (1 + 4294967294) >> 32 + 4294967294 = 4294967294",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 1U),
+ BPF_ALU32_IMM(BPF_MOV, R1, 4294967294U),
+ BPF_ALU32_REG(BPF_ADD, R0, R1),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_REG(BPF_ADD, R0, R1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 4294967294U } },
+ },
{
"ALU64_ADD_X: 1 + 2 = 3",
.u.insns_int = {
@@ -2812,6 +2826,20 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 1 } },
},
+ {
+ "ALU_SUB_X: (4294967295 - 1) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 4294967295U),
+ BPF_ALU32_IMM(BPF_MOV, R1, 1U),
+ BPF_ALU32_REG(BPF_SUB, R0, R1),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_REG(BPF_ADD, R0, R1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU64_SUB_X: 3 - 1 = 2",
.u.insns_int = {
@@ -3391,6 +3419,20 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 0xffffffff } },
},
+ {
+ "ALU_AND_X: (-1 & -1) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, -1UL),
+ BPF_LD_IMM64(R1, -1UL),
+ BPF_ALU32_REG(BPF_AND, R0, R1),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1U),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU64_AND_X: 3 & 2 = 2",
.u.insns_int = {
@@ -3533,6 +3575,20 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 0xffffffff } },
},
+ {
+ "ALU_OR_X: (0 & -1) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 0),
+ BPF_LD_IMM64(R1, -1UL),
+ BPF_ALU32_REG(BPF_OR, R0, R1),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1U),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU64_OR_X: 1 | 2 = 3",
.u.insns_int = {
@@ -3675,6 +3731,20 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 0xfffffffe } },
},
+ {
+ "ALU_XOR_X: (0 ^ -1) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 0),
+ BPF_LD_IMM64(R1, -1UL),
+ BPF_ALU32_REG(BPF_XOR, R0, R1),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1U),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU64_XOR_X: 5 ^ 6 = 3",
.u.insns_int = {
@@ -3817,6 +3887,20 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 0x80000000 } },
},
+ {
+ "ALU_LSH_X: (1 << 31) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 1),
+ BPF_ALU32_IMM(BPF_MOV, R1, 31),
+ BPF_ALU32_REG(BPF_LSH, R0, R1),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU64_LSH_X: 1 << 1 = 2",
.u.insns_int = {
@@ -3842,6 +3926,19 @@ static struct bpf_test tests[] = {
{ { 0, 0x80000000 } },
},
/* BPF_ALU | BPF_LSH | BPF_K */
+ {
+ "ALU_LSH_K: (1 << 31) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 1),
+ BPF_ALU32_IMM(BPF_LSH, R0, 31),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU_LSH_K: 1 << 1 = 2",
.u.insns_int = {
@@ -3911,6 +4008,20 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 1 } },
},
+ {
+ "ALU_RSH_X: (0x80000000 >> 0) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 0x80000000),
+ BPF_ALU32_IMM(BPF_MOV, R1, 0),
+ BPF_ALU32_REG(BPF_RSH, R0, R1),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU64_RSH_X: 2 >> 1 = 1",
.u.insns_int = {
@@ -3936,6 +4047,19 @@ static struct bpf_test tests[] = {
{ { 0, 1 } },
},
/* BPF_ALU | BPF_RSH | BPF_K */
+ {
+ "ALU_RSH_K: (0x80000000 >> 0) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 0x80000000),
+ BPF_ALU32_IMM(BPF_RSH, R0, 0),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU_RSH_K: 2 >> 1 = 1",
.u.insns_int = {
@@ -3993,7 +4117,34 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 0xffff00ff } },
},
+ {
+ "ALU_ARSH_X: (0x80000000 >> 0) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 0x80000000),
+ BPF_ALU32_IMM(BPF_MOV, R1, 0),
+ BPF_ALU32_REG(BPF_ARSH, R0, R1),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
/* BPF_ALU | BPF_ARSH | BPF_K */
+ {
+ "ALU_ARSH_K: (0x80000000 >> 0) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_LD_IMM64(R0, 0x80000000),
+ BPF_ALU32_IMM(BPF_ARSH, R0, 0),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU32_IMM(BPF_ADD, R0, 1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU_ARSH_K: 0xff00ff0000000000 >> 40 = 0xffffffffffff00ff",
.u.insns_int = {
@@ -4028,6 +4179,19 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 3 } },
},
+ {
+ "ALU_NEG: -(1) >> 32 + 1 = 1",
+ .u.insns_int = {
+ BPF_ALU32_IMM(BPF_MOV, R0, 1),
+ BPF_ALU32_IMM(BPF_NEG, R0, 0),
+ BPF_ALU64_IMM(BPF_RSH, R0, 32),
+ BPF_ALU64_IMM(BPF_ADD, R0, 1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
{
"ALU64_NEG: -(3) = -3",
.u.insns_int = {
--
2.19.1