util/fipstools/inject_hash/inject_hash.go - boringssl - Git at Google

 // Copyright (c) 2017, Google Inc.
 //
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
 //
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 // WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 // MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 // SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 // WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 // OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 // CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

 // inject_hash parses an archive containing a file object file. It finds a FIPS
 // module inside that object, calculates its hash and replaces the default hash
 // value in the object with the calculated value.
 package main

 import (
 	"bytes"
 	"crypto/hmac"
 	"crypto/sha256"
 	"debug/elf"
 	"encoding/binary"
 	"errors"
 	"flag"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 	"strings"

 	"boringssl.googlesource.com/boringssl/util/ar"
 	"boringssl.googlesource.com/boringssl/util/fipstools/fipscommon"
 )

 func do(outPath, oInput string, arInput string) error {
 	var objectBytes []byte
 	var isStatic bool
 	var perm os.FileMode

 	if len(arInput) > 0 {
 		isStatic = true

 		if len(oInput) > 0 {
 			return fmt.Errorf("-in-archive and -in-object are mutually exclusive")
 		}

 		fi, err := os.Stat(arInput)
 		if err != nil {
 			return err
 		}
 		perm = fi.Mode()

 		arFile, err := os.Open(arInput)
 		if err != nil {
 			return err
 		}
 		defer arFile.Close()

 		ar, err := ar.ParseAR(arFile)
 		if err != nil {
 			return err
 		}

 		if len(ar) != 1 {
 			return fmt.Errorf("expected one file in archive, but found %d", len(ar))
 		}

 		for _, contents := range ar {
 			objectBytes = contents
 		}
 	} else if len(oInput) > 0 {
 		fi, err := os.Stat(oInput)
 		if err != nil {
 			return err
 		}
 		perm = fi.Mode()

 		if objectBytes, err = ioutil.ReadFile(oInput); err != nil {
 			return err
 		}
 		isStatic = strings.HasSuffix(oInput, ".o")
 	} else {
 		return fmt.Errorf("exactly one of -in-archive or -in-object is required")
 	}

 	object, err := elf.NewFile(bytes.NewReader(objectBytes))
 	if err != nil {
 		return errors.New("failed to parse object: " + err.Error())
 	}

 	// Find the .text and, optionally, .data sections.

 	var textSection, rodataSection *elf.Section
 	var textSectionIndex, rodataSectionIndex elf.SectionIndex
 	for i, section := range object.Sections {
 		switch section.Name {
 		case ".text":
 			textSectionIndex = elf.SectionIndex(i)
 			textSection = section
 		case ".rodata":
 			rodataSectionIndex = elf.SectionIndex(i)
 			rodataSection = section
 		}
 	}

 	if textSection == nil {
 		return errors.New("failed to find .text section in object")
 	}

 	// Find the starting and ending symbols for the module.

 	var textStart, textEnd, rodataStart, rodataEnd *uint64

 	symbols, err := object.Symbols()
 	if err != nil {
 		return errors.New("failed to parse symbols: " + err.Error())
 	}

 	for _, symbol := range symbols {
 		var base uint64
 		switch symbol.Section {
 		case textSectionIndex:
 			base = textSection.Addr
 		case rodataSectionIndex:
 			if rodataSection == nil {
 				continue
 			}
 			base = rodataSection.Addr
 		default:
 			continue
 		}

 		if isStatic {
 			// Static objects appear to have different semantics about whether symbol
 			// values are relative to their section or not.
 			base = 0
 		} else if symbol.Value < base {
 			return fmt.Errorf("symbol %q at %x, which is below base of %x", symbol.Name, symbol.Value, base)
 		}

 		value := symbol.Value - base
 		switch symbol.Name {
 		case "BORINGSSL_bcm_text_start":
 			if textStart != nil {
 				return errors.New("duplicate start symbol found")
 			}
 			textStart = &value
 		case "BORINGSSL_bcm_text_end":
 			if textEnd != nil {
 				return errors.New("duplicate end symbol found")
 			}
 			textEnd = &value
 		case "BORINGSSL_bcm_rodata_start":
 			if rodataStart != nil {
 				return errors.New("duplicate rodata start symbol found")
 			}
 			rodataStart = &value
 		case "BORINGSSL_bcm_rodata_end":
 			if rodataEnd != nil {
 				return errors.New("duplicate rodata end symbol found")
 			}
 			rodataEnd = &value
 		default:
 			continue
 		}
 	}

 	if textStart == nil || textEnd == nil {
 		return errors.New("could not find .text module boundaries in object")
 	}

 	if (rodataStart == nil) != (rodataSection == nil) {
 		return errors.New("rodata start marker inconsistent with rodata section presence")
 	}

 	if (rodataStart != nil) != (rodataEnd != nil) {
 		return errors.New("rodata marker presence inconsistent")
 	}

 	if max := textSection.Size; *textStart > max || *textStart > *textEnd || *textEnd > max {
 		return fmt.Errorf("invalid module .text boundaries: start: %x, end: %x, max: %x", *textStart, *textEnd, max)
 	}

 	if rodataSection != nil {
 		if max := rodataSection.Size; *rodataStart > max || *rodataStart > *rodataEnd || *rodataEnd > max {
 			return fmt.Errorf("invalid module .rodata boundaries: start: %x, end: %x, max: %x", *rodataStart, *rodataEnd, max)
 		}
 	}

 	// Extract the module from the .text section and hash it.

 	text := textSection.Open()
 	if _, err := text.Seek(int64(*textStart), 0); err != nil {
 		return errors.New("failed to seek to module start in .text: " + err.Error())
 	}
 	moduleText := make([]byte, *textEnd-*textStart)
 	if _, err := io.ReadFull(text, moduleText); err != nil {
 		return errors.New("failed to read .text: " + err.Error())
 	}

 	// Maybe extract the module's read-only data too
 	var moduleROData []byte
 	if rodataSection != nil {
 		rodata := rodataSection.Open()
 		if _, err := rodata.Seek(int64(*rodataStart), 0); err != nil {
 			return errors.New("failed to seek to module start in .rodata: " + err.Error())
 		}
 		moduleROData = make([]byte, *rodataEnd-*rodataStart)
 		if _, err := io.ReadFull(rodata, moduleROData); err != nil {
 			return errors.New("failed to read .rodata: " + err.Error())
 		}
 	}

 	var zeroKey [64]byte
 	mac := hmac.New(sha256.New, zeroKey[:])

 	if moduleROData != nil {
 		var lengthBytes [8]byte
 		binary.LittleEndian.PutUint64(lengthBytes[:], uint64(len(moduleText)))
 		mac.Write(lengthBytes[:])
 		mac.Write(moduleText)

 		binary.LittleEndian.PutUint64(lengthBytes[:], uint64(len(moduleROData)))
 		mac.Write(lengthBytes[:])
 		mac.Write(moduleROData)
 	} else {
 		mac.Write(moduleText)
 	}
 	calculated := mac.Sum(nil)

 	// Replace the default hash value in the object with the calculated
 	// value and write it out.

 	offset := bytes.Index(objectBytes, fipscommon.UninitHashValue[:])
 	if offset < 0 {
 		return errors.New("did not find uninitialised hash value in object file")
 	}

 	if bytes.Index(objectBytes[offset+1:], fipscommon.UninitHashValue[:]) >= 0 {
 		return errors.New("found two occurrences of uninitialised hash value in object file")
 	}

 	copy(objectBytes[offset:], calculated)

 	return ioutil.WriteFile(outPath, objectBytes, perm & 0777)
 }

 func main() {
 	arInput := flag.String("in-archive", "", "Path to a .a file")
 	oInput := flag.String("in-object", "", "Path to a .o file")
 	outPath := flag.String("o", "", "Path to output object")

 	flag.Parse()

 	if err := do(*outPath, *oInput, *arInput); err != nil {
 		fmt.Fprintf(os.Stderr, "%s\n", err)
 		os.Exit(1)
 	}
 }
	// Copyright (c) 2017, Google Inc.
	//
	// Permission to use, copy, modify, and/or distribute this software for any
	// purpose with or without fee is hereby granted, provided that the above
	// copyright notice and this permission notice appear in all copies.
	//
	// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
	// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
	// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
	// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

	// inject_hash parses an archive containing a file object file. It finds a FIPS
	// module inside that object, calculates its hash and replaces the default hash
	// value in the object with the calculated value.
	package main

	import (
	"bytes"
	"crypto/hmac"
	"crypto/sha256"
	"debug/elf"
	"encoding/binary"
	"errors"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"strings"

	"boringssl.googlesource.com/boringssl/util/ar"
	"boringssl.googlesource.com/boringssl/util/fipstools/fipscommon"
	)

	func do(outPath, oInput string, arInput string) error {
	var objectBytes []byte
	var isStatic bool
	var perm os.FileMode

	if len(arInput) > 0 {
	isStatic = true

	if len(oInput) > 0 {
	return fmt.Errorf("-in-archive and -in-object are mutually exclusive")
	}

	fi, err := os.Stat(arInput)
	if err != nil {
	return err
	}
	perm = fi.Mode()

	arFile, err := os.Open(arInput)
	if err != nil {
	return err
	}
	defer arFile.Close()

	ar, err := ar.ParseAR(arFile)
	if err != nil {
	return err
	}

	if len(ar) != 1 {
	return fmt.Errorf("expected one file in archive, but found %d", len(ar))
	}

	for _, contents := range ar {
	objectBytes = contents
	}
	} else if len(oInput) > 0 {
	fi, err := os.Stat(oInput)
	if err != nil {
	return err
	}
	perm = fi.Mode()

	if objectBytes, err = ioutil.ReadFile(oInput); err != nil {
	return err
	}
	isStatic = strings.HasSuffix(oInput, ".o")
	} else {
	return fmt.Errorf("exactly one of -in-archive or -in-object is required")
	}

	object, err := elf.NewFile(bytes.NewReader(objectBytes))
	if err != nil {
	return errors.New("failed to parse object: " + err.Error())
	}

	// Find the .text and, optionally, .data sections.

	var textSection, rodataSection *elf.Section
	var textSectionIndex, rodataSectionIndex elf.SectionIndex
	for i, section := range object.Sections {
	switch section.Name {
	case ".text":
	textSectionIndex = elf.SectionIndex(i)
	textSection = section
	case ".rodata":
	rodataSectionIndex = elf.SectionIndex(i)
	rodataSection = section
	}
	}

	if textSection == nil {
	return errors.New("failed to find .text section in object")
	}

	// Find the starting and ending symbols for the module.

	var textStart, textEnd, rodataStart, rodataEnd *uint64

	symbols, err := object.Symbols()
	if err != nil {
	return errors.New("failed to parse symbols: " + err.Error())
	}

	for _, symbol := range symbols {
	var base uint64
	switch symbol.Section {
	case textSectionIndex:
	base = textSection.Addr
	case rodataSectionIndex:
	if rodataSection == nil {
	continue
	}
	base = rodataSection.Addr
	default:
	continue
	}

	if isStatic {
	// Static objects appear to have different semantics about whether symbol
	// values are relative to their section or not.
	base = 0
	} else if symbol.Value < base {
	return fmt.Errorf("symbol %q at %x, which is below base of %x", symbol.Name, symbol.Value, base)
	}

	value := symbol.Value - base
	switch symbol.Name {
	case "BORINGSSL_bcm_text_start":
	if textStart != nil {
	return errors.New("duplicate start symbol found")
	}
	textStart = &value
	case "BORINGSSL_bcm_text_end":
	if textEnd != nil {
	return errors.New("duplicate end symbol found")
	}
	textEnd = &value
	case "BORINGSSL_bcm_rodata_start":
	if rodataStart != nil {
	return errors.New("duplicate rodata start symbol found")
	}
	rodataStart = &value
	case "BORINGSSL_bcm_rodata_end":
	if rodataEnd != nil {
	return errors.New("duplicate rodata end symbol found")
	}
	rodataEnd = &value
	default:
	continue
	}
	}

	if textStart == nil \|\| textEnd == nil {
	return errors.New("could not find .text module boundaries in object")
	}

	if (rodataStart == nil) != (rodataSection == nil) {
	return errors.New("rodata start marker inconsistent with rodata section presence")
	}

	if (rodataStart != nil) != (rodataEnd != nil) {
	return errors.New("rodata marker presence inconsistent")
	}

	if max := textSection.Size; textStart > max \|\| textStart > textEnd \|\| textEnd > max {
	return fmt.Errorf("invalid module .text boundaries: start: %x, end: %x, max: %x", textStart, textEnd, max)
	}

	if rodataSection != nil {
	if max := rodataSection.Size; rodataStart > max \|\| rodataStart > rodataEnd \|\| rodataEnd > max {
	return fmt.Errorf("invalid module .rodata boundaries: start: %x, end: %x, max: %x", rodataStart, rodataEnd, max)
	}
	}

	// Extract the module from the .text section and hash it.

	text := textSection.Open()
	if _, err := text.Seek(int64(*textStart), 0); err != nil {
	return errors.New("failed to seek to module start in .text: " + err.Error())
	}
	moduleText := make([]byte, textEnd-textStart)
	if _, err := io.ReadFull(text, moduleText); err != nil {
	return errors.New("failed to read .text: " + err.Error())
	}

	// Maybe extract the module's read-only data too
	var moduleROData []byte
	if rodataSection != nil {
	rodata := rodataSection.Open()
	if _, err := rodata.Seek(int64(*rodataStart), 0); err != nil {
	return errors.New("failed to seek to module start in .rodata: " + err.Error())
	}
	moduleROData = make([]byte, rodataEnd-rodataStart)
	if _, err := io.ReadFull(rodata, moduleROData); err != nil {
	return errors.New("failed to read .rodata: " + err.Error())
	}
	}

	var zeroKey [64]byte
	mac := hmac.New(sha256.New, zeroKey[:])

	if moduleROData != nil {
	var lengthBytes [8]byte
	binary.LittleEndian.PutUint64(lengthBytes[:], uint64(len(moduleText)))
	mac.Write(lengthBytes[:])
	mac.Write(moduleText)

	binary.LittleEndian.PutUint64(lengthBytes[:], uint64(len(moduleROData)))
	mac.Write(lengthBytes[:])
	mac.Write(moduleROData)
	} else {
	mac.Write(moduleText)
	}
	calculated := mac.Sum(nil)

	// Replace the default hash value in the object with the calculated
	// value and write it out.

	offset := bytes.Index(objectBytes, fipscommon.UninitHashValue[:])
	if offset < 0 {
	return errors.New("did not find uninitialised hash value in object file")
	}

	if bytes.Index(objectBytes[offset+1:], fipscommon.UninitHashValue[:]) >= 0 {
	return errors.New("found two occurrences of uninitialised hash value in object file")
	}

	copy(objectBytes[offset:], calculated)

	return ioutil.WriteFile(outPath, objectBytes, perm & 0777)
	}

	func main() {
	arInput := flag.String("in-archive", "", "Path to a .a file")
	oInput := flag.String("in-object", "", "Path to a .o file")
	outPath := flag.String("o", "", "Path to output object")

	flag.Parse()

	if err := do(outPath, oInput, *arInput); err != nil {
	fmt.Fprintf(os.Stderr, "%s\n", err)
	os.Exit(1)
	}
	}