From fb6ddd680c6c2723dcc682a5a0ecb8070b25395c Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Wed, 14 Sep 2022 09:02:58 +0100
Subject: [PATCH] compress: fix crash due to nil metadata #6434
Before this fix, if an error ocurred reading the metadata, it could be
set as nil and then used, causing a crash.
This fix changes the readMetadata function so it returns an error, and
the error is always set if the metadata returned is nil.
---
backend/compress/compress.go | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)
diff --git a/backend/compress/compress.go b/backend/compress/compress.go
index 2ae192eb9..b0ada83c6 100644
--- a/backend/compress/compress.go
+++ b/backend/compress/compress.go
@@ -367,9 +367,9 @@ func (f *Fs) NewObject(ctx context.Context, remote string) (fs.Object, error) {
if err != nil {
return nil, err
}
- meta := readMetadata(ctx, mo)
- if meta == nil {
- return nil, errors.New("error decoding metadata")
+ meta, err := readMetadata(ctx, mo)
+ if err != nil {
+ return nil, fmt.Errorf("error decoding metadata: %w", err)
}
// Create our Object
o, err := f.Fs.NewObject(ctx, makeDataName(remote, meta.CompressionMetadata.Size, meta.Mode))
@@ -1040,24 +1040,19 @@ func newMetadata(size int64, mode int, cmeta sgzip.GzipMetadata, md5 string, mim
}
// This function will read the metadata from a metadata object.
-func readMetadata(ctx context.Context, mo fs.Object) (meta *ObjectMetadata) {
+func readMetadata(ctx context.Context, mo fs.Object) (meta *ObjectMetadata, err error) {
// Open our meradata object
rc, err := mo.Open(ctx)
if err != nil {
- return nil
+ return nil, err
}
- defer func() {
- err := rc.Close()
- if err != nil {
- fs.Errorf(mo, "Error closing object: %v", err)
- }
- }()
+ defer fs.CheckClose(rc, &err)
jr := json.NewDecoder(rc)
meta = new(ObjectMetadata)
if err = jr.Decode(meta); err != nil {
- return nil
+ return nil, err
}
- return meta
+ return meta, nil
}
// Remove removes this object
@@ -1167,7 +1162,7 @@ func (o *Object) loadMetadataIfNotLoaded(ctx context.Context) (err error) {
return err
}
if o.meta == nil {
- o.meta = readMetadata(ctx, o.mo)
+ o.meta, err = readMetadata(ctx, o.mo)
}
return err
}