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authorJakob Unterwurzacher2017-03-12 21:11:02 +0100
committerJakob Unterwurzacher2017-03-12 21:11:02 +0100
commit14038a1644f17f50b113a05d09a2a0a3b3e973b2 (patch)
tree41a0ac555231b210fc9b89a5d055cf2158fc6f65
parentd36d53c9bbf1b1f1c34578d443770672528e4466 (diff)
fusefrontend: readFileID: reject files that consist only of a header
A header-only file will be considered empty (this is not supposed to happen). This makes File ID poisoning more difficult.
-rw-r--r--internal/fusefrontend/file.go13
1 files changed, 11 insertions, 2 deletions
diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go
index 5fe866b..dac7510 100644
--- a/internal/fusefrontend/file.go
+++ b/internal/fusefrontend/file.go
@@ -91,11 +91,20 @@ func (f *file) SetInode(n *nodefs.Inode) {
// readFileID loads the file header from disk and extracts the file ID.
// Returns io.EOF if the file is empty.
func (f *file) readFileID() ([]byte, error) {
- buf := make([]byte, contentenc.HeaderLen)
- _, err := f.fd.ReadAt(buf, 0)
+ // We read +1 byte to determine if the file has actual content
+ // and not only the header. A header-only file will be considered empty.
+ // This makes File ID poisoning more difficult.
+ readLen := contentenc.HeaderLen + 1
+ buf := make([]byte, readLen)
+ n, err := f.fd.ReadAt(buf, 0)
if err != nil {
+ if err == io.EOF && n != 0 {
+ tlog.Warn.Printf("ino%d: readFileID: incomplete file, got %d instead of %d bytes",
+ f.devIno.ino, n, readLen)
+ }
return nil, err
}
+ buf = buf[:contentenc.HeaderLen]
h, err := contentenc.ParseHeader(buf)
if err != nil {
return nil, err