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pkg/tarsum: fix panic with dynamic buffer

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When read is called on a tarsum with a two different read sizes, specifically the second call larger than the first, the dynamic buffer does not get reallocated causing a slice read error.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
This commit is contained in:
Derek McGowan 2014-09-25 15:58:35 -07:00
parent 56483ba9b4
commit 6a33e70bd5
2 changed files with 18 additions and 2 deletions
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4
tarsum/tarsum.go
View file

@ -179,7 +179,7 @@ func (ts *tarSum) Read(buf []byte) (int, error) {
if ts.finished { if ts.finished {
return ts.bufWriter.Read(buf) return ts.bufWriter.Read(buf)
} }
if ts.bufData == nil { if len(ts.bufData) < len(buf) {
switch { switch {
case len(buf) <= buf8K: case len(buf) <= buf8K:
ts.bufData = make([]byte, buf8K) ts.bufData = make([]byte, buf8K)
@ -191,7 +191,7 @@ func (ts *tarSum) Read(buf []byte) (int, error) {
ts.bufData = make([]byte, len(buf)) ts.bufData = make([]byte, len(buf))
} }
} }
buf2 := ts.bufData[:len(buf)-1] buf2 := ts.bufData[:len(buf)]
n, err := ts.tarR.Read(buf2) n, err := ts.tarR.Read(buf2)
if err != nil { if err != nil {

16
tarsum/tarsum_test.go
View file

@ -274,6 +274,22 @@ func TestTarSums(t *testing.T) {
t.Errorf("%q :: %q", err, layer.filename) t.Errorf("%q :: %q", err, layer.filename)
continue continue
} }
// Read variable number of bytes to test dynamic buffer
dBuf := make([]byte, 1)
_, err = ts.Read(dBuf)
if err != nil {
t.Errorf("failed to read 1B from %s: %s", layer.filename, err)
continue
}
dBuf = make([]byte, 16*1024)
_, err = ts.Read(dBuf)
if err != nil {
t.Errorf("failed to read 16KB from %s: %s", layer.filename, err)
continue
}
// Read and discard remaining bytes
_, err = io.Copy(ioutil.Discard, ts) _, err = io.Copy(ioutil.Discard, ts)
if err != nil { if err != nil {
t.Errorf("failed to copy from %s: %s", layer.filename, err) t.Errorf("failed to copy from %s: %s", layer.filename, err)