From 5b7b3fa9a4d8ca4ad08d6648752e28ee66f0ffae Mon Sep 17 00:00:00 2001
From: Ophestra <cat@gensokyo.uk>
Date: Mon, 3 Feb 2025 18:10:29 +0900
Subject: helper/seccomp: implement reader interface via pipe

This also does not require the libc tmpfile call.

BPF programs emitted by libseccomp seems to be deterministic. The tests would catch regressions as it verifies the program against known good output backed by manual testing.

Signed-off-by: Ophestra <cat@gensokyo.uk>
---
 helper/seccomp/export_test.go | 123 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 helper/seccomp/export_test.go

(limited to 'helper/seccomp/export_test.go')

diff --git a/helper/seccomp/export_test.go b/helper/seccomp/export_test.go
new file mode 100644
index 00000000..bbafa3b1
--- /dev/null
+++ b/helper/seccomp/export_test.go
@@ -0,0 +1,123 @@
+package seccomp_test
+
+import (
+	"crypto/sha512"
+	"errors"
+	"io"
+	"slices"
+	"syscall"
+	"testing"
+
+	"git.gensokyo.uk/security/fortify/helper/seccomp"
+	"git.gensokyo.uk/security/fortify/internal/fmsg"
+)
+
+func TestExport(t *testing.T) {
+	testCases := []struct {
+		name    string
+		opts    seccomp.SyscallOpts
+		want    []byte
+		wantErr bool
+	}{
+		{"compat", 0, []byte{
+			0x95, 0xec, 0x69, 0xd0, 0x17, 0x73, 0x3e, 0x07,
+			0x21, 0x60, 0xe0, 0xda, 0x80, 0xfd, 0xeb, 0xec,
+			0xdf, 0x27, 0xae, 0x81, 0x66, 0xf5, 0xe2, 0xa7,
+			0x31, 0x27, 0x0c, 0x98, 0xea, 0x2d, 0x29, 0x46,
+			0xcb, 0x52, 0x31, 0x02, 0x90, 0x63, 0x66, 0x8a,
+			0xf2, 0x15, 0x87, 0x91, 0x55, 0xda, 0x21, 0xac,
+			0xa7, 0x9b, 0x07, 0x0e, 0x04, 0xc0, 0xee, 0x9a,
+			0xcd, 0xf5, 0x8f, 0x55, 0xcf, 0xa8, 0x15, 0xa5,
+		}, false},
+		{"base", seccomp.FlagExt, []byte{
+			0xdc, 0x7f, 0x2e, 0x1c, 0x5e, 0x82, 0x9b, 0x79,
+			0xeb, 0xb7, 0xef, 0xc7, 0x59, 0x15, 0x0f, 0x54,
+			0xa8, 0x3a, 0x75, 0xc8, 0xdf, 0x6f, 0xee, 0x4d,
+			0xce, 0x5d, 0xad, 0xc4, 0x73, 0x6c, 0x58, 0x5d,
+			0x4d, 0xee, 0xbf, 0xeb, 0x3c, 0x79, 0x69, 0xaf,
+			0x3a, 0x07, 0x7e, 0x90, 0xb7, 0x7b, 0xb4, 0x74,
+			0x1d, 0xb0, 0x5d, 0x90, 0x99, 0x7c, 0x86, 0x59,
+			0xb9, 0x58, 0x91, 0x20, 0x6a, 0xc9, 0x95, 0x2d,
+		}, false},
+		{"everything", seccomp.FlagExt |
+			seccomp.FlagDenyNS | seccomp.FlagDenyTTY | seccomp.FlagDenyDevel |
+			seccomp.FlagMultiarch | seccomp.FlagLinux32 | seccomp.FlagCan |
+			seccomp.FlagBluetooth, []byte{
+			0xe9, 0x9d, 0xd3, 0x45, 0xe1, 0x95, 0x41, 0x34,
+			0x73, 0xd3, 0xcb, 0xee, 0x07, 0xb4, 0xed, 0x57,
+			0xb9, 0x08, 0xbf, 0xa8, 0x9e, 0xa2, 0x07, 0x2f,
+			0xe9, 0x34, 0x82, 0x84, 0x7f, 0x50, 0xb5, 0xb7,
+			0x58, 0xda, 0x17, 0xe7, 0x4c, 0xa2, 0xbb, 0xc0,
+			0x08, 0x13, 0xde, 0x49, 0xa2, 0xb9, 0xbf, 0x83,
+			0x4c, 0x02, 0x4e, 0xd4, 0x88, 0x50, 0xbe, 0x69,
+			0xb6, 0x8a, 0x9a, 0x4c, 0x5f, 0x53, 0xa9, 0xdb,
+		}, false},
+		{"strict", seccomp.FlagExt |
+			seccomp.FlagDenyNS | seccomp.FlagDenyTTY | seccomp.FlagDenyDevel, []byte{
+			0xe8, 0x80, 0x29, 0x8d, 0xf2, 0xbd, 0x67, 0x51,
+			0xd0, 0x04, 0x0f, 0xc2, 0x1b, 0xc0, 0xed, 0x4c,
+			0x00, 0xf9, 0x5d, 0xc0, 0xd7, 0xba, 0x50, 0x6c,
+			0x24, 0x4d, 0x8b, 0x8c, 0xf6, 0x86, 0x6d, 0xba,
+			0x8e, 0xf4, 0xa3, 0x32, 0x96, 0xf2, 0x87, 0xb6,
+			0x6c, 0xcc, 0xc1, 0xd7, 0x8e, 0x97, 0x02, 0x65,
+			0x97, 0xf8, 0x4c, 0xc7, 0xde, 0xc1, 0x57, 0x3e,
+			0x14, 0x89, 0x60, 0xfb, 0xd3, 0x5c, 0xd7, 0x35,
+		}, false},
+		{"strict compat", 0 |
+			seccomp.FlagDenyNS | seccomp.FlagDenyTTY | seccomp.FlagDenyDevel, []byte{
+			0x39, 0x87, 0x1b, 0x93, 0xff, 0xaf, 0xc8, 0xb9,
+			0x79, 0xfc, 0xed, 0xc0, 0xb0, 0xc3, 0x7b, 0x9e,
+			0x03, 0x92, 0x2f, 0x5b, 0x02, 0x74, 0x8d, 0xc5,
+			0xc3, 0xc1, 0x7c, 0x92, 0x52, 0x7f, 0x6e, 0x02,
+			0x2e, 0xde, 0x1f, 0x48, 0xbf, 0xf5, 0x92, 0x46,
+			0xea, 0x45, 0x2c, 0x0d, 0x1d, 0xe5, 0x48, 0x27,
+			0x80, 0x8b, 0x1a, 0x6f, 0x84, 0xf3, 0x2b, 0xbd,
+			0xe1, 0xaa, 0x02, 0xae, 0x30, 0xee, 0xdc, 0xfa,
+		}, false},
+	}
+
+	buf := make([]byte, 8)
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			seccomp.CPrintln = fmsg.Println
+			t.Cleanup(func() { seccomp.CPrintln = nil })
+
+			e := seccomp.New(tc.opts)
+			digest := sha512.New()
+
+			if _, err := io.CopyBuffer(digest, e, buf); (err != nil) != tc.wantErr {
+				t.Errorf("Exporter: error = %v, wantErr %v", err, tc.wantErr)
+				return
+			}
+			if err := e.Close(); err != nil {
+				t.Errorf("Close: error = %v", err)
+				return
+			}
+			if got := digest.Sum(nil); slices.Compare(got, tc.want) != 0 {
+				t.Fatalf("Export() hash = %x, want %x",
+					got, tc.want)
+				return
+			}
+		})
+	}
+
+	t.Run("close without use", func(t *testing.T) {
+		e := seccomp.New(0)
+		if err := e.Close(); !errors.Is(err, syscall.EINVAL) {
+			t.Errorf("Close: error = %v", err)
+			return
+		}
+	})
+
+	t.Run("close partial read", func(t *testing.T) {
+		e := seccomp.New(0)
+		if _, err := e.Read(make([]byte, 0)); err != nil {
+			t.Errorf("Read: error = %v", err)
+			return
+		}
+		if err := e.Close(); err == nil || err.Error() != "seccomp_export_bpf failed: operation canceled" {
+			t.Errorf("Close: error = %v", err)
+			return
+		}
+	})
+}
-- 
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