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authorJakob Unterwurzacher2017-07-29 16:13:38 +0200
committerJakob Unterwurzacher2017-07-29 16:15:49 +0200
commitd12aa577156101a1c6a05765de751f0a54b58aa8 (patch)
tree7d06f260636c449a7cc4488393c958c909fadb07 /internal/fusefrontend_reverse/virtualfile.go
parentd5133ca5ac4f241ff22ef145a3605a9fdb341bb6 (diff)
fusefronted_reverse: fix ino collision between .name and .diriv files
A directory with a long name has two associated virtual files: the .name file and the .diriv files. These used to get the same inode number: $ ls -di1 * */* 33313535 gocryptfs.longname.2togDFouca9mrTwtfF1RNW5DZRAQY8alaR7wO_Xd5Zw 1000000000033313535 gocryptfs.longname.2togDFouca9mrTwtfF1RNW5DZRAQY8alaR7wO_Xd5Zw/gocryptfs.diriv 1000000000033313535 gocryptfs.longname.2togDFouca9mrTwtfF1RNW5DZRAQY8alaR7wO_Xd5Zw.name With this change we use another prefix (2 instead of 1) for .name files. $ ls -di1 * */* 33313535 gocryptfs.longname.2togDFouca9mrTwtfF1RNW5DZRAQY8alaR7wO_Xd5Zw 1000000000033313535 gocryptfs.longname.2togDFouca9mrTwtfF1RNW5DZRAQY8alaR7wO_Xd5Zw/gocryptfs.diriv 2000000000033313535 gocryptfs.longname.2togDFouca9mrTwtfF1RNW5DZRAQY8alaR7wO_Xd5Zw.name
Diffstat (limited to 'internal/fusefrontend_reverse/virtualfile.go')
-rw-r--r--internal/fusefrontend_reverse/virtualfile.go32
1 files changed, 23 insertions, 9 deletions
diff --git a/internal/fusefrontend_reverse/virtualfile.go b/internal/fusefrontend_reverse/virtualfile.go
index 5d5d80d..05b8349 100644
--- a/internal/fusefrontend_reverse/virtualfile.go
+++ b/internal/fusefrontend_reverse/virtualfile.go
@@ -1,6 +1,7 @@
package fusefrontend_reverse
import (
+ "log"
"syscall"
"github.com/hanwen/go-fuse/fuse"
@@ -14,12 +15,19 @@ const (
// virtualFileMode is the mode to use for virtual files (gocryptfs.diriv and
// *.name). They are always readable, as stated in func Access
virtualFileMode = syscall.S_IFREG | 0444
- // virtualInoBase is the start of the inode number range that is used
- // for virtual files.
+ // inoBaseDirIV is the start of the inode number range that is used
+ // for virtual gocryptfs.diriv files. inoBaseNameFile is the thing for
+ // *.name files.
// The value 10^19 is just below 2^60. A power of 10 has been chosen so the
// "ls -li" output (which is base-10) is easy to read.
- // 10^19 is the largest power of 10 that is smaller than UINT64_MAX/2.
- virtualInoBase = uint64(1000000000000000000)
+ // 10^19 is the largest power of 10 that is smaller than
+ // INT64_MAX (=UINT64_MAX/2). This avoids signedness issues.
+ inoBaseDirIV = uint64(1000000000000000000)
+ inoBaseNameFile = uint64(2000000000000000000)
+ // inoBaseMin marks the start of the inode number space that is
+ // reserved for virtual files. It is the lowest of the inoBaseXXX values
+ // above.
+ inoBaseMin = inoBaseDirIV
)
func (rfs *ReverseFS) newDirIVFile(cRelPath string) (nodefs.File, fuse.Status) {
@@ -28,7 +36,7 @@ func (rfs *ReverseFS) newDirIVFile(cRelPath string) (nodefs.File, fuse.Status) {
if err != nil {
return nil, fuse.ToStatus(err)
}
- return rfs.newVirtualFile(pathiv.Derive(cDir, pathiv.PurposeDirIV), absDir)
+ return rfs.newVirtualFile(pathiv.Derive(cDir, pathiv.PurposeDirIV), absDir, inoBaseDirIV)
}
type virtualFile struct {
@@ -38,17 +46,23 @@ type virtualFile struct {
content []byte
// absolute path to a parent file
parentFile string
+ // inode number of a virtual file is inode of parent file plus inoBase
+ inoBase uint64
}
// newVirtualFile creates a new in-memory file that does not have a representation
// on disk. "content" is the file content. Timestamps and file owner are copied
// from "parentFile" (absolute plaintext path). For a "gocryptfs.diriv" file, you
// would use the parent directory as "parentFile".
-func (rfs *ReverseFS) newVirtualFile(content []byte, parentFile string) (nodefs.File, fuse.Status) {
+func (rfs *ReverseFS) newVirtualFile(content []byte, parentFile string, inoBase uint64) (nodefs.File, fuse.Status) {
+ if inoBase < inoBaseMin {
+ log.Panicf("BUG: virtual inode number base %d is below reserved space", inoBase)
+ }
return &virtualFile{
File: nodefs.NewDefaultFile(),
content: content,
parentFile: parentFile,
+ inoBase: inoBase,
}, fuse.OK
}
@@ -72,12 +86,12 @@ func (f *virtualFile) GetAttr(a *fuse.Attr) fuse.Status {
tlog.Debug.Printf("GetAttr: Lstat %q: %v\n", f.parentFile, err)
return fuse.ToStatus(err)
}
- if st.Ino > virtualInoBase {
+ if st.Ino > inoBaseMin {
tlog.Warn.Printf("virtualFile.GetAttr: parent file inode number %d crosses reserved space, max=%d. Returning EOVERFLOW.",
- st.Ino, virtualInoBase)
+ st.Ino, inoBaseMin)
return fuse.ToStatus(syscall.EOVERFLOW)
}
- st.Ino = st.Ino + virtualInoBase
+ st.Ino = st.Ino + f.inoBase
st.Size = int64(len(f.content))
st.Mode = virtualFileMode
st.Nlink = 1