support universal (fat) mach-o binary files (#4278)

Signed-off-by: Joseph Shapiro <joeyashapiro@gmail.com>

syft/file/cataloger/executable/macho.go

@@ -3,6 +3,7 @@ package executable
 import (
 	"debug/macho"
 
+	"github.com/anchore/syft/internal"
 	"github.com/anchore/syft/syft/file"
 	"github.com/anchore/syft/syft/internal/unionreader"
 )
@@ -19,20 +20,38 @@ const (
 func findMachoFeatures(data *file.Executable, reader unionreader.UnionReader) error {
 	// TODO: support security features
 
-	// TODO: support multi-architecture binaries
+	// a universal binary may have multiple architectures, so we need to check each one
-	f, err := macho.NewFile(reader)
+	readers, err := unionreader.GetReaders(reader)
 	if err != nil {
 		return err
 	}
 
-	libs, err := f.ImportedLibraries()
+	var libs []string
-	if err != nil {
+	for _, r := range readers {
-		return err
+		f, err := macho.NewFile(r)
+		if err != nil {
+			return err
+		}
+
+		rLibs, err := f.ImportedLibraries()
+		if err != nil {
+			return err
+		}
+		libs = append(libs, rLibs...)
+
+		// TODO handle only some having entrypoints/exports? If that is even practical
+		// only check for entrypoint if we don't already have one
+		if !data.HasEntrypoint {
+			data.HasEntrypoint = machoHasEntrypoint(f)
+		}
+		// only check for exports if we don't already have them
+		if !data.HasExports {
+			data.HasExports = machoHasExports(f)
+		}
 	}
 
-	data.ImportedLibraries = libs
+	// de-duplicate libraries
-	data.HasEntrypoint = machoHasEntrypoint(f)
+	data.ImportedLibraries = internal.NewSet(libs...).ToSlice()
-	data.HasExports = machoHasExports(f)
 
 	return nil
 }

syft/file/cataloger/executable/macho_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/anchore/syft/syft/file"
 	"github.com/anchore/syft/syft/internal/unionreader"
 )
 
@@ -83,3 +84,39 @@ func Test_machoHasExports(t *testing.T) {
 		})
 	}
 }
+
+func Test_machoUniversal(t *testing.T) {
+	readerForFixture := func(t *testing.T, fixture string) unionreader.UnionReader {
+		t.Helper()
+		f, err := os.Open(filepath.Join("test-fixtures/shared-info", fixture))
+		require.NoError(t, err)
+		return f
+	}
+
+	tests := []struct {
+		name    string
+		fixture string
+		want    file.Executable
+	}{
+		{
+			name:    "universal lib",
+			fixture: "bin/libhello_universal.dylib",
+			want:    file.Executable{HasExports: true, HasEntrypoint: false},
+		},
+		{
+			name:    "universal application",
+			fixture: "bin/hello_mac_universal",
+			want:    file.Executable{HasExports: false, HasEntrypoint: true},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var data file.Executable
+			err := findMachoFeatures(&data, readerForFixture(t, tt.fixture))
+			require.NoError(t, err)
+
+			assert.Equal(t, tt.want.HasEntrypoint, data.HasEntrypoint)
+			assert.Equal(t, tt.want.HasExports, data.HasExports)
+		})
+	}
+}

syft/file/cataloger/executable/test-fixtures/shared-info/project/hello/Makefile

@@ -2,13 +2,13 @@
 
 BIN=../../bin
 
-all: $(BIN)/hello_linux $(BIN)/hello.exe $(BIN)/hello_mac
+all: $(BIN)/hello_linux $(BIN)/hello.exe $(BIN)/hello_mac $(BIN)/hello_mac_universal
 
 linux: $(BIN)/libhello.so
 
 windows: $(BIN)/libhello.dll
 
-mac: $(BIN)/libhello.dylib
+mac: $(BIN)/libhello.dylib $(BIN)/hello_mac_universal
 
 $(BIN)/hello_linux:
 	gcc hello.c -o $(BIN)/hello_linux
@@ -19,5 +19,8 @@ $(BIN)/hello.exe:
 $(BIN)/hello_mac:
 	o64-clang hello.c -o $(BIN)/hello_mac
 
+$(BIN)/hello_mac_universal:
+	o64-clang -arch arm64 -arch x86_64 hello.c -o $(BIN)/hello_mac_universal
+
 clean:
-	rm -f $(BIN)/hello_linux $(BIN)/hello.exe $(BIN)/hello_mac
+	rm -f $(BIN)/hello_linux $(BIN)/hello.exe $(BIN)/hello_mac $(BIN)/hello_mac_universal

syft/file/cataloger/executable/test-fixtures/shared-info/project/libhello/Makefile

@@ -2,13 +2,13 @@
 
 BIN=../../bin
 
-all:  $(BIN)/libhello.so  $(BIN)/libhello.dll $(BIN)/libhello.dylib
+all:  $(BIN)/libhello.so  $(BIN)/libhello.dll $(BIN)/libhello.dylib $(BIN)/libhello_universal.dylib
 
 linux: $(BIN)/libhello.so
 
 windows: $(BIN)/libhello.dll
 
-mac: $(BIN)/libhello.dylib
+mac: $(BIN)/libhello.dylib $(BIN)/libhello_universal.dylib
 
 $(BIN)/libhello.so:
 	gcc -shared -fPIC -o $(BIN)/libhello.so hello.c
@@ -19,5 +19,8 @@ $(BIN)/libhello.dll:
 $(BIN)/libhello.dylib:
 	o64-clang -dynamiclib -o $(BIN)/libhello.dylib hello.c
 
+$(BIN)/libhello_universal.dylib:
+	o64-clang -dynamiclib -arch arm64 -arch x86_64 hello.c -o $(BIN)/libhello_universal.dylib
+
 clean:
-	rm -f $(BIN)/libhello.so $(BIN)/hello.dll $(BIN)/libhello.dylib $(BIN)/libhello.a
+	rm -f $(BIN)/libhello.so $(BIN)/hello.dll $(BIN)/libhello.dylib $(BIN)/libhello.a $(BIN)/libhello_universal.dylib