From 840e7dad513b86f454573ad415701c0199f78d30 Mon Sep 17 00:00:00 2001
From: TomSweeneyRedHat <tsweeney@redhat.com>
Date: Tue, 24 Mar 2020 20:10:22 -0400
Subject: [PATCH] Fix potential CVE in tarfile w/ symlink
Stealing @nalind 's workaround to avoid refetching
content after a file read failure. Under the right
circumstances that could be a symlink to a file meant
to overwrite a good file with bad data.
Testing:
```
goodstuff
[1] 14901
127.0.0.1 - - [24/Mar/2020 20:15:50] "GET / HTTP/1.1" 200 -
127.0.0.1 - - [24/Mar/2020 20:15:50] "GET / HTTP/1.1" 200 -
no FROM statement found
goodstuff
```
Signed-off-by: TomSweeneyRedHat <tsweeney@redhat.com>
---
imagebuildah/util.go | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff -up a/imagebuildah/util.go.CVE-2020-10696 b/imagebuildah/util.go
--- a/imagebuildah/util.go.CVE-2020-10696
+++ b/imagebuildah/util.go
@@ -12,6 +12,7 @@ import (
"github.com/containers/buildah"
"github.com/containers/storage/pkg/chrootarchive"
+ "github.com/containers/storage/pkg/ioutils"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
@@ -47,7 +48,7 @@ func downloadToDirectory(url, dir string
}
dockerfile := filepath.Join(dir, "Dockerfile")
// Assume this is a Dockerfile
- if err := ioutil.WriteFile(dockerfile, body, 0600); err != nil {
+ if err := ioutils.AtomicWriteFile(dockerfile, body, 0600); err != nil {
return errors.Wrapf(err, "Failed to write %q to %q", url, dockerfile)
}
}