Files
visor/pkg/bpf/interpreter_test.go
Etienne PerotandgVisor bot 056a85f39d Mark all ABI structs with structs.HostLayout; verify this remains true.
This change marks all ABI-related structs with `structs.HostLayout`, which was
introduced in Go 1.23: https://pkg.go.dev/[email protected]#HostLayout
This is intended to force the Go compiler to preserve the layout of the
struct, removing it from the liberty of reordering fields as it sees fit.

Adds a check automatically generated by our `go_library` rule wrapper which
verifies this recursively for all exported structs in a package.

Fixes issue #10693.

PiperOrigin-RevId: 860238103
2026-01-23 13:45:28 -08:00

1078 lines
34 KiB
Go

// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package bpf
import (
"reflect"
"slices"
"testing"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/hostarch"
"gvisor.dev/gvisor/pkg/marshal"
)
func TestCompilationErrors(t *testing.T) {
for _, test := range []struct {
// desc is the test's description.
desc string
// insns is the BPF instructions to be compiled.
insns []Instruction
// expectedErr is the expected compilation error.
expectedErr error
}{
{
desc: "Instructions must not be nil",
expectedErr: Error{InvalidInstructionCount, 0},
},
{
desc: "Instructions must not be empty",
insns: []Instruction{},
expectedErr: Error{InvalidInstructionCount, 0},
},
{
desc: "A program must end with a return",
insns: make([]Instruction, MaxInstructions),
expectedErr: Error{InvalidEndOfProgram, MaxInstructions - 1},
},
{
desc: "A program must have MaxInstructions or fewer instructions",
insns: append(make([]Instruction, MaxInstructions), Stmt(Ret|K, 0)),
expectedErr: Error{InvalidInstructionCount, MaxInstructions + 1},
},
{
desc: "A load from an invalid M register is a compilation error",
insns: []Instruction{
Stmt(Ld|Mem|W, ScratchMemRegisters), // A = M[16]
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{InvalidRegister, 0},
},
{
desc: "A store to an invalid M register is a compilation error",
insns: []Instruction{
Stmt(St, ScratchMemRegisters), // M[16] = A
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{InvalidRegister, 0},
},
{
desc: "Division by literal zero is a compilation error",
insns: []Instruction{
Stmt(Alu|Div|K, 0), // A /= 0
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{DivisionByZero, 0},
},
{
desc: "An unconditional jump outside of the program is a compilation error",
insns: []Instruction{
Jump(Jmp|Ja, 1, 0, 0), // jmp nextpc+1
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{InvalidJumpTarget, 0},
},
{
desc: "A conditional jump outside of the program in the true case is a compilation error",
insns: []Instruction{
Jump(Jmp|Jeq|K, 0, 1, 0), // if (A == K) jmp nextpc+1
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{InvalidJumpTarget, 0},
},
{
desc: "A conditional jump outside of the program in the false case is a compilation error",
insns: []Instruction{
Jump(Jmp|Jeq|K, 0, 0, 1), // if (A != K) jmp nextpc+1
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{InvalidJumpTarget, 0},
},
} {
t.Run(test.desc, func(t *testing.T) {
_, err := Compile(test.insns, false)
if err != test.expectedErr {
t.Errorf("expected error %q, got error %q", test.expectedErr, err)
}
})
}
}
func TestExecErrors(t *testing.T) {
for _, test := range []struct {
// desc is the test's description.
desc string
// insns is the BPF instructions to be executed.
insns []Instruction
// expectedErr is the expected execution error.
expectedErr error
}{
{
desc: "An out-of-bounds load of input data is an execution error",
insns: []Instruction{
Stmt(Ld|Abs|B, 0), // A = input[0]
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{InvalidLoad, 0},
},
{
desc: "Division by zero at runtime is an execution error",
insns: []Instruction{
Stmt(Alu|Div|X, 0), // A /= X
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{DivisionByZero, 0},
},
{
desc: "Modulo zero at runtime is an execution error",
insns: []Instruction{
Stmt(Alu|Mod|X, 0), // A %= X
Stmt(Ret|K, 0), // return 0
},
expectedErr: Error{DivisionByZero, 0},
},
} {
t.Run(test.desc, func(t *testing.T) {
p, err := Compile(test.insns, false)
if err != nil {
t.Fatalf("unexpected compilation error: %v", err)
}
inp := Input{}
execution, err := InstrumentedExec[NativeEndian](p, inp)
if err != test.expectedErr {
t.Fatalf("expected execution error %q, got (%v, %v)", test.expectedErr, execution, err)
}
ret, err := Exec[NativeEndian](p, inp)
if err != test.expectedErr {
t.Fatalf("expected execution error %q, got (%d, %v)", test.expectedErr, ret, err)
}
optimizedProgram, err := Compile(test.insns, true)
if err != nil {
t.Fatalf("unexpected compilation error: %v", err)
}
if _, err := InstrumentedExec[NativeEndian](optimizedProgram, inp); err != test.expectedErr {
t.Fatalf("expected execution error from optimized program %q, got (%v, %v)", test.expectedErr, execution, err)
}
})
}
}
func TestValidInstructions(t *testing.T) {
want := func(ex ExecutionMetrics) func(insns []Instruction, input []byte) ExecutionMetrics {
return func(insns []Instruction, input []byte) ExecutionMetrics {
return ex
}
}
allCoveredNoneReadAndReturns := func(ret uint32) func(insns []Instruction, input []byte) ExecutionMetrics {
return func(insns []Instruction, input []byte) ExecutionMetrics {
coverage := make([]bool, len(insns))
for i := range insns {
coverage[i] = true
}
return ExecutionMetrics{
Coverage: coverage,
InputAccessed: make([]bool, len(input)),
ReturnValue: ret,
}
}
}
for _, test := range []struct {
// desc is the test's description.
desc string
// insns is the BPF instructions to be compiled.
insns []Instruction
// input is the input data. Note that input will be read as big-endian.
input Input
// expected is the expected result of executing the BPF program.
// It takes in the instructions and input that the test will run.
expected func(insns []Instruction, input []byte) ExecutionMetrics
}{
{
desc: "Return of immediate",
insns: []Instruction{
Stmt(Ret|K, 42), // return 42
},
expected: allCoveredNoneReadAndReturns(42),
},
{
desc: "Load of immediate into A",
insns: []Instruction{
Stmt(Ld|Imm|W, 42), // A = 42
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(42),
},
{
desc: "Load of immediate into X and copying of X into A",
insns: []Instruction{
Stmt(Ldx|Imm|W, 42), // X = 42
Stmt(Misc|Tax, 0), // A = X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(42),
},
{
desc: "Copying of A into X and back",
insns: []Instruction{
Stmt(Ld|Imm|W, 42), // A = 42
Stmt(Misc|Txa, 0), // X = A
Stmt(Ld|Imm|W, 0), // A = 0
Stmt(Misc|Tax, 0), // A = X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(42),
},
{
desc: "Load of 32-bit input by absolute offset into A",
insns: []Instruction{
Stmt(Ld|Abs|W, 1), // A = input[1..4]
Stmt(Ret|A, 0), // return A
},
input: []byte{0x00, 0x11, 0x22, 0x33, 0x44, 0x55},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true},
InputAccessed: []bool{false, true, true, true, true, false},
ReturnValue: hostarch.ByteOrder.Uint32([]byte{0x11, 0x22, 0x33, 0x44}),
}),
},
{
desc: "Load of 16-bit input by absolute offset into A",
insns: []Instruction{
Stmt(Ld|Abs|H, 1), // A = input[1..2]
Stmt(Ret|A, 0), // return A
},
input: []byte{0x00, 0x11, 0x22, 0x33},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true},
InputAccessed: []bool{false, true, true, false},
ReturnValue: uint32(hostarch.ByteOrder.Uint16([]byte{0x11, 0x22})),
}),
},
{
desc: "Load of 8-bit input by absolute offset into A",
insns: []Instruction{
Stmt(Ld|Abs|B, 1), // A = input[1]
Stmt(Ret|A, 0), // return A
},
input: []byte{0x00, 0x11, 0x22},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true},
InputAccessed: []bool{false, true, false},
ReturnValue: 0x11,
}),
},
{
desc: "Load of 32-bit input by relative offset into A",
insns: []Instruction{
Stmt(Ldx|Imm|W, 1), // X = 1
Stmt(Ld|Ind|W, 1), // A = input[X+1..X+4]
Stmt(Ret|A, 0), // return A
},
input: []byte{0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true},
InputAccessed: []bool{false, false, true, true, true, true, false},
ReturnValue: hostarch.ByteOrder.Uint32([]byte{0x22, 0x33, 0x44, 0x55}),
}),
},
{
desc: "Load of 16-bit input by relative offset into A",
insns: []Instruction{
Stmt(Ldx|Imm|W, 1), // X = 1
Stmt(Ld|Ind|H, 1), // A = input[X+1..X+2]
Stmt(Ret|A, 0), // return A
},
input: []byte{0x00, 0x11, 0x22, 0x33, 0x44},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true},
InputAccessed: []bool{false, false, true, true, false},
ReturnValue: uint32(hostarch.ByteOrder.Uint16([]byte{0x22, 0x33})),
}),
},
{
desc: "Load of 8-bit input by relative offset into A",
insns: []Instruction{
Stmt(Ldx|Imm|W, 1), // X = 1
Stmt(Ld|Ind|B, 1), // A = input[X+1]
Stmt(Ret|A, 0), // return A
},
input: []byte{0x00, 0x11, 0x22, 0x33},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true},
InputAccessed: []bool{false, false, true, false},
ReturnValue: 0x22,
}),
},
{
desc: "Load/store between A and scratch memory",
insns: []Instruction{
Stmt(Ld|Imm|W, 42), // A = 42
Stmt(St, 2), // M[2] = A
Stmt(Ld|Imm|W, 0), // A = 0
Stmt(Ld|Mem|W, 2), // A = M[2]
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(42),
},
{
desc: "Load/store between X and scratch memory",
insns: []Instruction{
Stmt(Ldx|Imm|W, 42), // X = 42
Stmt(Stx, 3), // M[3] = X
Stmt(Ldx|Imm|W, 0), // X = 0
Stmt(Ldx|Mem|W, 3), // X = M[3]
Stmt(Misc|Tax, 0), // A = X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(42),
},
{
desc: "Load of input length into A",
insns: []Instruction{
Stmt(Ld|Len|W, 0), // A = len(input)
Stmt(Ret|A, 0), // return A
},
input: []byte{1, 2, 3},
expected: allCoveredNoneReadAndReturns(3),
},
{
desc: "Load of input length into X",
insns: []Instruction{
Stmt(Ldx|Len|W, 0), // X = len(input)
Stmt(Misc|Tax, 0), // A = X
Stmt(Ret|A, 0), // return A
},
input: []byte{1, 2, 3},
expected: allCoveredNoneReadAndReturns(3),
},
{
desc: "Load of MSH (?) into X",
insns: []Instruction{
Stmt(Ldx|Msh|B, 0), // X = 4*(input[0]&0xf)
Stmt(Misc|Tax, 0), // A = X
Stmt(Ret|A, 0), // return A
},
input: []byte{0xf1},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true},
InputAccessed: []bool{true},
ReturnValue: 4,
}),
},
{
desc: "Addition of immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Stmt(Alu|Add|K, 20), // A += 20
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(30),
},
{
desc: "Addition of X",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Stmt(Ldx|Imm|W, 20), // X = 20
Stmt(Alu|Add|X, 0), // A += X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(30),
},
{
desc: "Subtraction of immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 30), // A = 30
Stmt(Alu|Sub|K, 20), // A -= 20
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(10),
},
{
desc: "Subtraction of X",
insns: []Instruction{
Stmt(Ld|Imm|W, 30), // A = 30
Stmt(Ldx|Imm|W, 20), // X = 20
Stmt(Alu|Sub|X, 0), // A -= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(10),
},
{
desc: "Multiplication of immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 2), // A = 2
Stmt(Alu|Mul|K, 3), // A *= 3
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(6),
},
{
desc: "Multiplication of X",
insns: []Instruction{
Stmt(Ld|Imm|W, 2), // A = 2
Stmt(Ldx|Imm|W, 3), // X = 3
Stmt(Alu|Mul|X, 0), // A *= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(6),
},
{
desc: "Division by immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 6), // A = 6
Stmt(Alu|Div|K, 3), // A /= 3
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(2),
},
{
desc: "Division by X",
insns: []Instruction{
Stmt(Ld|Imm|W, 6), // A = 6
Stmt(Ldx|Imm|W, 3), // X = 3
Stmt(Alu|Div|X, 0), // A /= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(2),
},
{
desc: "Modulo immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 17), // A = 17
Stmt(Alu|Mod|K, 7), // A %= 7
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(3),
},
{
desc: "Modulo X",
insns: []Instruction{
Stmt(Ld|Imm|W, 17), // A = 17
Stmt(Ldx|Imm|W, 7), // X = 7
Stmt(Alu|Mod|X, 0), // A %= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(3),
},
{
desc: "Arithmetic negation",
insns: []Instruction{
Stmt(Ld|Imm|W, 1), // A = 1
Stmt(Alu|Neg, 0), // A = -A
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(0xffffffff),
},
{
desc: "Bitwise OR with immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xff00aa55), // A = 0xff00aa55
Stmt(Alu|Or|K, 0xff0055aa), // A |= 0xff0055aa
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(0xff00ffff),
},
{
desc: "Bitwise OR with X",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xff00aa55), // A = 0xff00aa55
Stmt(Ldx|Imm|W, 0xff0055aa), // X = 0xff0055aa
Stmt(Alu|Or|X, 0), // A |= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(0xff00ffff),
},
{
desc: "Bitwise AND with immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xff00aa55), // A = 0xff00aa55
Stmt(Alu|And|K, 0xff0055aa), // A &= 0xff0055aa
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(0xff000000),
},
{
desc: "Bitwise AND with X",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xff00aa55), // A = 0xff00aa55
Stmt(Ldx|Imm|W, 0xff0055aa), // X = 0xff0055aa
Stmt(Alu|And|X, 0), // A &= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(0xff000000),
},
{
desc: "Bitwise XOR with immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xff00aa55), // A = 0xff00aa55
Stmt(Alu|Xor|K, 0xff0055aa), // A ^= 0xff0055aa
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(0x0000ffff),
},
{
desc: "Bitwise XOR with X",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xff00aa55), // A = 0xff00aa55
Stmt(Ldx|Imm|W, 0xff0055aa), // X = 0xff0055aa
Stmt(Alu|Xor|X, 0), // A ^= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(0x0000ffff),
},
{
desc: "Left shift by immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 1), // A = 1
Stmt(Alu|Lsh|K, 5), // A <<= 5
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(32),
},
{
desc: "Left shift by X",
insns: []Instruction{
Stmt(Ld|Imm|W, 1), // A = 1
Stmt(Ldx|Imm|W, 5), // X = 5
Stmt(Alu|Lsh|X, 0), // A <<= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(32),
},
{
desc: "Right shift by immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xffffffff), // A = 0xffffffff
Stmt(Alu|Rsh|K, 31), // A >>= 31
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(1),
},
{
desc: "Right shift by X",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xffffffff), // A = 0xffffffff
Stmt(Ldx|Imm|W, 31), // X = 31
Stmt(Alu|Rsh|X, 0), // A >>= X
Stmt(Ret|A, 0), // return A
},
expected: allCoveredNoneReadAndReturns(1),
},
{
desc: "Unconditional jump",
insns: []Instruction{
Jump(Jmp|Ja, 1, 0, 0), // jmp nextpc+1
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, false, true},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A == immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 42), // A = 42
Jump(Jmp|Jeq|K, 42, 1, 2), // if (A == 42) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, false, true, false},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A != immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 41), // A = 41
Jump(Jmp|Jeq|K, 42, 1, 2), // if (A == 42) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, false, false, true},
InputAccessed: []bool{},
ReturnValue: 2,
}),
},
{
desc: "Jump when A == X",
insns: []Instruction{
Stmt(Ld|Imm|W, 42), // A = 42
Stmt(Ldx|Imm|W, 42), // X = 42
Jump(Jmp|Jeq|X, 0, 1, 2), // if (A == X) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, true, false},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A != X",
insns: []Instruction{
Stmt(Ld|Imm|W, 42), // A = 42
Stmt(Ldx|Imm|W, 41), // X = 41
Jump(Jmp|Jeq|X, 0, 1, 2), // if (A == X) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, false, true},
InputAccessed: []bool{},
ReturnValue: 2,
}),
},
{
desc: "Jump when A > immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Jump(Jmp|Jgt|K, 9, 1, 2), // if (A > 9) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, false, true, false},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A <= immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Jump(Jmp|Jgt|K, 10, 1, 2), // if (A > 10) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, false, false, true},
InputAccessed: []bool{},
ReturnValue: 2,
}),
},
{
desc: "Jump when A > X",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Stmt(Ldx|Imm|W, 9), // X = 9
Jump(Jmp|Jgt|X, 0, 1, 2), // if (A > X) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, true, false},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A <= X",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Stmt(Ldx|Imm|W, 10), // X = 10
Jump(Jmp|Jgt|X, 0, 1, 2), // if (A > X) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, false, true},
InputAccessed: []bool{},
ReturnValue: 2,
}),
},
{
desc: "Jump when A >= immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Jump(Jmp|Jge|K, 10, 1, 2), // if (A >= 10) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, false, true, false},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A < immediate",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Jump(Jmp|Jge|K, 11, 1, 2), // if (A >= 11) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, false, false, true},
InputAccessed: []bool{},
ReturnValue: 2,
}),
},
{
desc: "Jump when A >= X",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Stmt(Ldx|Imm|W, 10), // X = 10
Jump(Jmp|Jge|X, 0, 1, 2), // if (A >= X) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, true, false},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A < X",
insns: []Instruction{
Stmt(Ld|Imm|W, 10), // A = 10
Stmt(Ldx|Imm|W, 11), // X = 11
Jump(Jmp|Jge|X, 0, 1, 2), // if (A >= X) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, false, true},
InputAccessed: []bool{},
ReturnValue: 2,
}),
},
{
desc: "Jump when A & immediate != 0",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xff), // A = 0xff
Jump(Jmp|Jset|K, 0x101, 1, 2), // if (A & 0x101) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, false, true, false},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A & immediate == 0",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xfe), // A = 0xfe
Jump(Jmp|Jset|K, 0x101, 1, 2), // if (A & 0x101) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, false, false, true},
InputAccessed: []bool{},
ReturnValue: 2,
}),
},
{
desc: "Jump when A & X != 0",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xff), // A = 0xff
Stmt(Ldx|Imm|W, 0x101), // X = 0x101
Jump(Jmp|Jset|X, 0, 1, 2), // if (A & X) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, true, false},
InputAccessed: []bool{},
ReturnValue: 1,
}),
},
{
desc: "Jump when A & X == 0",
insns: []Instruction{
Stmt(Ld|Imm|W, 0xfe), // A = 0xfe
Stmt(Ldx|Imm|W, 0x101), // X = 0x101
Jump(Jmp|Jset|X, 0, 1, 2), // if (A & X) jmp nextpc+1 else jmp nextpc+2
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
Stmt(Ret|K, 2), // return 2
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, false, true},
InputAccessed: []bool{},
ReturnValue: 2,
}),
},
{
desc: "Optimizable program",
insns: []Instruction{
Stmt(Ld|Imm|W, 42), // A = 42
Jump(Jmp|Jeq|K, 42, 0, 1), // if (A == 42) jmp 0 else 1
Jump(Jmp|Ja, 1, 0, 0), // jmp 1
Jump(Jmp|Ja, 2, 0, 0), // jmp 2
Stmt(Ld|Imm|W, 37), // A = 37
Stmt(Ret|K, 0), // return 0
Stmt(Ret|K, 1), // return 1
},
expected: want(ExecutionMetrics{
Coverage: []bool{true, true, true, false, true, true, false},
InputAccessed: []bool{},
ReturnValue: 0,
}),
},
} {
t.Run(test.desc, func(t *testing.T) {
p, err := Compile(test.insns, false)
if err != nil {
t.Fatalf("unexpected compilation error: %v", err)
}
want := test.expected(test.insns, test.input)
execution, err := InstrumentedExec[NativeEndian](p, test.input)
if err != nil {
t.Fatalf("unexpected execution error: %v", err)
}
if !reflect.DeepEqual(execution, want) {
t.Fatalf("expected %s, got %s", want.String(), execution.String())
}
retFast, err := Exec[NativeEndian](p, test.input)
if err != nil {
t.Fatalf("unexpected execution error during fast execution: %v", err)
}
if retFast != execution.ReturnValue {
t.Fatalf("instrumented execution returned %d, fast execution returned %d", execution.ReturnValue, retFast)
}
optimizedProgram, err := Compile(test.insns, true)
if err != nil {
t.Fatalf("unexpected compilation error: %v", err)
}
retOptimized, err := InstrumentedExec[NativeEndian](optimizedProgram, test.input)
if err != nil {
t.Fatalf("unexpected execution error: %v", err)
}
if retOptimized.ReturnValue != retFast {
t.Fatalf("expected return value from optimized version: got %d, non-optimized execution returned %d", retOptimized.ReturnValue, retFast)
}
if !slices.Equal(retOptimized.InputAccessed, execution.InputAccessed) {
t.Fatalf("expected input read coverage from optimized version: got %s, non-optimized execution was %s", retOptimized.String(), execution.String())
}
})
}
}
// Seccomp filter example given in Linux's
// Documentation/networking/filter.txt, translated to bytecode using the
// Linux kernel tree's tools/net/bpf_asm.
var sampleFilter = []Instruction{
RawInstruction(0x20, 0, 0, 0x00000004), // ld [4] /* offsetof(struct seccomp_data, arch) */
RawInstruction(0x15, 0, 11, 0xc000003e), // jne #0xc000003e, bad /* AUDIT_ARCH_X86_64 */
RawInstruction(0x20, 0, 0, 0000000000), // ld [0] /* offsetof(struct seccomp_data, nr) */
RawInstruction(0x15, 10, 0, 0x0000000f), // jeq #15, good /* __NR_rt_sigreturn */
RawInstruction(0x15, 9, 0, 0x000000e7), // jeq #231, good /* __NR_exit_group */
RawInstruction(0x15, 8, 0, 0x0000003c), // jeq #60, good /* __NR_exit */
RawInstruction(0x15, 7, 0, 0000000000), // jeq #0, good /* __NR_read */
RawInstruction(0x15, 6, 0, 0x00000001), // jeq #1, good /* __NR_write */
RawInstruction(0x15, 5, 0, 0x00000005), // jeq #5, good /* __NR_fstat */
RawInstruction(0x15, 4, 0, 0x00000009), // jeq #9, good /* __NR_mmap */
RawInstruction(0x15, 3, 0, 0x0000000e), // jeq #14, good /* __NR_rt_sigprocmask */
RawInstruction(0x15, 2, 0, 0x0000000d), // jeq #13, good /* __NR_rt_sigaction */
RawInstruction(0x15, 1, 0, 0x00000023), // jeq #35, good /* __NR_nanosleep */
RawInstruction(0x06, 0, 0, 0000000000), // bad: ret #0 /* SECCOMP_RET_KILL */
RawInstruction(0x06, 0, 0, 0x7fff0000), // good: ret #0x7fff0000 /* SECCOMP_RET_ALLOW */
}
func TestSimpleFilter(t *testing.T) {
p, err := Compile(sampleFilter, false)
if err != nil {
t.Fatalf("Unexpected compilation error: %v", err)
}
// linux.SeccompData is 64 bytes long.
// The first 4 bytes is the syscall number.
// The next 4 bytes is the architecture.
// The last 56 bytes are the instruction pointer and the syscall arguments,
// which this sample program never accesses.
noRIPOrSyscallArgsAccess := make([]bool, 56)
for _, test := range []struct {
// desc is the test's description.
desc string
// SeccompData is the input data.
data linux.SeccompData
// expected is the expected execution result of the BPF program.
expected ExecutionMetrics
}{
{
desc: "Invalid arch is rejected",
data: linux.SeccompData{Nr: 1 /* x86 exit */, Arch: 0x40000003 /* AUDIT_ARCH_I386 */},
expected: ExecutionMetrics{
ReturnValue: 0,
Coverage: []bool{
true, // ld [4] /* offsetof(struct seccomp_data, arch) */
true, // jne #0xc000003e, bad /* AUDIT_ARCH_X86_64 */
false, // ld [0] /* offsetof(struct seccomp_data, nr) */
false, // jeq #15, good /* __NR_rt_sigreturn */
false, // jeq #231, good /* __NR_exit_group */
false, // jeq #60, good /* __NR_exit */
false, // jeq #0, good /* __NR_read */
false, // jeq #1, good /* __NR_write */
false, // jeq #5, good /* __NR_fstat */
false, // jeq #9, good /* __NR_mmap */
false, // jeq #14, good /* __NR_rt_sigprocmask */
false, // jeq #13, good /* __NR_rt_sigaction */
false, // jeq #35, good /* __NR_nanosleep */
true, // bad: ret #0 /* SECCOMP_RET_KILL */
false, // good: ret #0x7fff0000 /* SECCOMP_RET_ALLOW */
},
InputAccessed: append(
[]bool{
false, false, false, false, // Syscall number
true, true, true, true, // Architecture
},
noRIPOrSyscallArgsAccess...),
},
},
{
desc: "Disallowed syscall is rejected",
data: linux.SeccompData{Nr: 105 /* __NR_setuid */, Arch: 0xc000003e},
expected: ExecutionMetrics{
ReturnValue: 0,
Coverage: []bool{
true, // ld [4] /* offsetof(struct seccomp_data, arch) */
true, // jne #0xc000003e, bad /* AUDIT_ARCH_X86_64 */
true, // ld [0] /* offsetof(struct seccomp_data, nr) */
true, // jeq #15, good /* __NR_rt_sigreturn */
true, // jeq #231, good /* __NR_exit_group */
true, // jeq #60, good /* __NR_exit */
true, // jeq #0, good /* __NR_read */
true, // jeq #1, good /* __NR_write */
true, // jeq #5, good /* __NR_fstat */
true, // jeq #9, good /* __NR_mmap */
true, // jeq #14, good /* __NR_rt_sigprocmask */
true, // jeq #13, good /* __NR_rt_sigaction */
true, // jeq #35, good /* __NR_nanosleep */
true, // bad: ret #0 /* SECCOMP_RET_KILL */
false, // good: ret #0x7fff0000 /* SECCOMP_RET_ALLOW */
},
InputAccessed: append(
[]bool{
true, true, true, true, // Syscall number
true, true, true, true, // Architecture
},
noRIPOrSyscallArgsAccess...),
},
},
{
desc: "Allowed syscall is indeed allowed",
data: linux.SeccompData{Nr: 231 /* __NR_exit_group */, Arch: 0xc000003e},
expected: ExecutionMetrics{
ReturnValue: 0x7fff0000, /* SECCOMP_RET_ALLOW */
Coverage: []bool{
true, // ld [4] /* offsetof(struct seccomp_data, arch) */
true, // jne #0xc000003e, bad /* AUDIT_ARCH_X86_64 */
true, // ld [0] /* offsetof(struct seccomp_data, nr) */
true, // jeq #15, good /* __NR_rt_sigreturn */
true, // jeq #231, good /* __NR_exit_group */
false, // jeq #60, good /* __NR_exit */
false, // jeq #0, good /* __NR_read */
false, // jeq #1, good /* __NR_write */
false, // jeq #5, good /* __NR_fstat */
false, // jeq #9, good /* __NR_mmap */
false, // jeq #14, good /* __NR_rt_sigprocmask */
false, // jeq #13, good /* __NR_rt_sigaction */
false, // jeq #35, good /* __NR_nanosleep */
false, // bad: ret #0 /* SECCOMP_RET_KILL */
true, // good: ret #0x7fff0000 /* SECCOMP_RET_ALLOW */
},
InputAccessed: append(
[]bool{
true, true, true, true, // Syscall number
true, true, true, true, // Architecture
},
noRIPOrSyscallArgsAccess...),
},
},
} {
t.Run(test.desc, func(t *testing.T) {
execution, err := InstrumentedExec[NativeEndian](p, dataAsInput(&test.data))
if err != nil {
t.Fatalf("expected return value of %d, got execution error: %v", test.expected.ReturnValue, err)
}
if !reflect.DeepEqual(execution, test.expected) {
t.Errorf("expected %s, got %s", test.expected.String(), execution.String())
}
})
}
}
// asInput converts a seccompData to a bpf.Input.
func dataAsInput(data *linux.SeccompData) Input {
return marshal.Marshal(data)
}
// BenchmarkInterpreter benchmarks the execution of the sample filter
// for a sample syscall.
func BenchmarkInterpreter(b *testing.B) {
p, err := Compile(sampleFilter, true)
if err != nil {
b.Fatalf("Unexpected compilation error: %v", err)
}
data := dataAsInput(&linux.SeccompData{Nr: 231 /* __NR_exit_group */, Arch: 0xc000003e})
b.ResetTimer()
for i := 0; i < b.N; i++ {
if _, err := Exec[NativeEndian](p, data); err != nil {
b.Fatalf("Unexpected execution error: %v", err)
}
}
}
func BenchmarkInstrumentedInterpreter(b *testing.B) {
p, err := Compile(sampleFilter, true)
if err != nil {
b.Fatalf("Unexpected compilation error: %v", err)
}
data := dataAsInput(&linux.SeccompData{Nr: 231 /* __NR_exit_group */, Arch: 0xc000003e})
b.ResetTimer()
for i := 0; i < b.N; i++ {
if _, err := InstrumentedExec[NativeEndian](p, data); err != nil {
b.Fatalf("Unexpected execution error: %v", err)
}
}
}