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tarsum: name collision fix

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If a tar were constructed with duplicate file names, then depending on
the order, it could result in same tarsum.

Signed-off-by: Vincent Batts <vbatts@redhat.com>
This commit is contained in:
Vincent Batts 2014-09-04 16:13:50 -04:00
parent e32fdc563a
commit a705b08336
8 changed files with 197 additions and 14 deletions
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25
tarsum/tarsum.go
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@ -39,7 +39,7 @@ func NewTarSum(r io.Reader, dc bool, v Version) (TarSum, error) {
// checksums of a tar archive
type TarSum interface {
io.Reader
GetSums() map[string]string
GetSums() FileInfoSums
Sum([]byte) string
Version() Version
}
@ -54,7 +54,8 @@ type tarSum struct {
bufGz *bytes.Buffer
bufData []byte
h hash.Hash
sums map[string]string
sums FileInfoSums
fileCounter int64
currentFile string
finished bool
first bool
@ -126,7 +127,7 @@ func (ts *tarSum) Read(buf []byte) (int, error) {
ts.h = sha256.New()
ts.h.Reset()
ts.first = true
ts.sums = make(map[string]string)
ts.sums = FileInfoSums{}
}
if ts.finished {
@ -153,7 +154,8 @@ func (ts *tarSum) Read(buf []byte) (int, error) {
return 0, err
}
if !ts.first {
ts.sums[ts.currentFile] = hex.EncodeToString(ts.h.Sum(nil))
ts.sums = append(ts.sums, fileInfoSum{name: ts.currentFile, sum: hex.EncodeToString(ts.h.Sum(nil)), pos: ts.fileCounter})
ts.fileCounter++
ts.h.Reset()
} else {
ts.first = false
@ -218,25 +220,20 @@ func (ts *tarSum) Read(buf []byte) (int, error) {
}
func (ts *tarSum) Sum(extra []byte) string {
var sums []string
for _, sum := range ts.sums {
sums = append(sums, sum)
}
sort.Strings(sums)
ts.sums.SortBySums()
h := sha256.New()
if extra != nil {
h.Write(extra)
}
for _, sum := range sums {
log.Debugf("-->%s<--", sum)
h.Write([]byte(sum))
for _, fis := range ts.sums {
log.Debugf("-->%s<--", fis.Sum())
h.Write([]byte(fis.Sum()))
}
checksum := ts.Version().String() + "+sha256:" + hex.EncodeToString(h.Sum(nil))
log.Debugf("checksum processed: %s", checksum)
return checksum
}
func (ts *tarSum) GetSums() map[string]string {
func (ts *tarSum) GetSums() FileInfoSums {
return ts.sums
}