6285c65e3b
There are cc_binary_prebuilt modules in the tree that are shell scripts, and attempting to extract an elf ID from them results in an error. Ignore too short files and files missing the elf magic header the same way we do for elf files without an elf ID. Bug: 218888599 Test: Test_elfIdentifierFromReaderAt_BadElfFile Change-Id: If7117925ca2371a8ee61ba3616372f6e9b0fab0e
114 lines
3.2 KiB
Go
114 lines
3.2 KiB
Go
// Copyright 2022 Google Inc. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package main
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import (
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"bytes"
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"debug/elf"
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"encoding/binary"
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"reflect"
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"testing"
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)
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func Test_elfIdentifierFromReaderAt_BadElfFile(t *testing.T) {
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tests := []struct {
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name string
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contents string
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}{
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{
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name: "empty",
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contents: "",
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},
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{
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name: "text",
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contents: "#!/bin/bash\necho foobar",
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},
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{
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name: "empty elf",
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contents: emptyElfFile(),
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},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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buf := bytes.NewReader([]byte(tt.contents))
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_, err := elfIdentifierFromReaderAt(buf, "<>", false)
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if err == nil {
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t.Errorf("expected error reading bad elf file without allowMissing")
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}
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_, err = elfIdentifierFromReaderAt(buf, "<>", true)
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if err != nil {
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t.Errorf("expected no error reading bad elf file with allowMissing, got %q", err.Error())
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}
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})
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}
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}
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func Test_readNote(t *testing.T) {
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note := []byte{
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0x04, 0x00, 0x00, 0x00,
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0x10, 0x00, 0x00, 0x00,
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0x03, 0x00, 0x00, 0x00,
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0x47, 0x4e, 0x55, 0x00,
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0xca, 0xaf, 0x44, 0xd2, 0x82, 0x78, 0x68, 0xfe, 0xc0, 0x90, 0xa3, 0x43, 0x85, 0x36, 0x6c, 0xc7,
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}
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descs, err := readNote(bytes.NewBuffer(note), binary.LittleEndian)
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if err != nil {
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t.Fatalf("unexpected error in readNote: %s", err)
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}
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expectedDescs := map[string][]byte{
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"GNU\x00": []byte{0xca, 0xaf, 0x44, 0xd2, 0x82, 0x78, 0x68, 0xfe, 0xc0, 0x90, 0xa3, 0x43, 0x85, 0x36, 0x6c, 0xc7},
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}
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if !reflect.DeepEqual(descs, expectedDescs) {
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t.Errorf("incorrect return, want %#v got %#v", expectedDescs, descs)
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}
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}
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// emptyElfFile returns an elf file header with no program headers or sections.
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func emptyElfFile() string {
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ident := [elf.EI_NIDENT]byte{}
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identBuf := bytes.NewBuffer(ident[0:0:elf.EI_NIDENT])
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binary.Write(identBuf, binary.LittleEndian, []byte("\x7fELF"))
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binary.Write(identBuf, binary.LittleEndian, elf.ELFCLASS64)
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binary.Write(identBuf, binary.LittleEndian, elf.ELFDATA2LSB)
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binary.Write(identBuf, binary.LittleEndian, elf.EV_CURRENT)
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binary.Write(identBuf, binary.LittleEndian, elf.ELFOSABI_LINUX)
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binary.Write(identBuf, binary.LittleEndian, make([]byte, 8))
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header := elf.Header64{
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Ident: ident,
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Type: uint16(elf.ET_EXEC),
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Machine: uint16(elf.EM_X86_64),
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Version: uint32(elf.EV_CURRENT),
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Entry: 0,
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Phoff: uint64(binary.Size(elf.Header64{})),
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Shoff: uint64(binary.Size(elf.Header64{})),
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Flags: 0,
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Ehsize: uint16(binary.Size(elf.Header64{})),
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Phentsize: 0x38,
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Phnum: 0,
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Shentsize: 0x40,
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Shnum: 0,
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Shstrndx: 0,
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}
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buf := &bytes.Buffer{}
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binary.Write(buf, binary.LittleEndian, header)
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return buf.String()
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}
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