Ensure that symlink names are completely read

A single Read(buf) from the payload does not necessarily read the whole content of the payload. Use ioutil.ReadAll() to ensure that we always read the whole symlink name. Signed-off-by: Roman Mohr <[email protected]>
rmohr · Jan 27, 2021 · debad0c · debad0c
1 parent 10fedd5
commit debad0c
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/pkg/rpm/cpio2tar.go b/pkg/rpm/cpio2tar.go
@@ -20,6 +20,7 @@ import (
 	"archive/tar"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"time"
 
 	"github.com/sassoftware/go-rpmutils/cpio"
@@ -98,8 +99,8 @@ func Tar(rs io.Reader, tarfile *tar.Writer, noSymlinksAndDirs bool, capabilities
 				continue
 			}
 			tarHeader.Typeflag = tar.TypeSymlink
-			buf := make([]byte, entry.Header.Filesize())
-			if _, err := entry.Payload.Read(buf); err != nil {
+			buf, err := ioutil.ReadAll(entry.Payload)
+			if err != nil {
 				return err
 			}
 			tarHeader.Linkname = string(buf)

diff --git a/pkg/rpm/tar.go b/pkg/rpm/tar.go
@@ -4,6 +4,7 @@ import (
 	"archive/tar"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -207,8 +208,8 @@ func CPIOToTarHeader(entry *cpio.CpioEntry) (*tar.Header, error) {
 		tarHeader.Typeflag = tar.TypeFifo
 	case cpio.S_ISLNK:
 		tarHeader.Typeflag = tar.TypeSymlink
-		buf := make([]byte, entry.Header.Filesize())
-		if _, err := entry.Payload.Read(buf); err != nil {
+		buf, err := ioutil.ReadAll(entry.Payload)
+		if err != nil {
 			return nil, err
 		}
 		tarHeader.Linkname = string(buf)