rawx: accept chunk IDs shorter than 64 hexdigits

Now it will accept between 24 and 64 hexdigits. Accepting less than 24
digits (96 bits) would lead to a high risk of collisions (it's just a
feeling, I didn't do the math).

rawx/chunk_info.go

@@ -312,7 +312,7 @@ func (chunk *chunkInfo) retrieveContentFullpathHeader(headers *http.Header) erro
 	chunk.ContentVersion = version
 
 	contentID, err := url.PathUnescape(fullpath[4])
-	if err != nil || !isHexaString(contentID, 0) {
+	if err != nil || !isHexaString(contentID, 0, 64) {
 		return errInvalidHeader
 	}
 	headerContentID := headers.Get(HeaderNameContentID)
@@ -345,7 +345,8 @@ func retrieveDestinationHeader(headers *http.Header, rawx *rawxService, srcChunk
 		return chunk, os.ErrPermission
 	}
 	chunk.ChunkID = filepath.Base(filepath.Clean(dstURL.Path))
-	if !isHexaString(chunk.ChunkID, 64) {
+	if !isHexaString(chunk.ChunkID, 24, 64) {
+		LogWarning("%s did not parse as hexadecimal string", chunk.ChunkID)
 		return chunk, errInvalidHeader
 	}
 	chunk.ChunkID = strings.ToUpper(chunk.ChunkID)
@@ -380,7 +381,7 @@ func retrieveHeaders(headers *http.Header, chunkID string) (chunkInfo, error) {
 
 	chunk.MetachunkHash = headers.Get(HeaderNameMetachunkChecksum)
 	if chunk.MetachunkHash != "" {
-		if !isHexaString(chunk.MetachunkHash, 0) {
+		if !isHexaString(chunk.MetachunkHash, 0, 64) {
 			return chunk, errInvalidHeader
 		}
 		chunk.MetachunkHash = strings.ToUpper(chunk.MetachunkHash)
@@ -394,7 +395,7 @@ func retrieveHeaders(headers *http.Header, chunkID string) (chunkInfo, error) {
 
 	chunk.ChunkHash = headers.Get(HeaderNameChunkChecksum)
 	if chunk.ChunkHash != "" {
-		if !isHexaString(chunk.ChunkHash, 0) {
+		if !isHexaString(chunk.ChunkHash, 0, 64) {
 			return chunk, errInvalidHeader
 		}
 		chunk.ChunkHash = strings.ToUpper(chunk.ChunkHash)
@@ -417,7 +418,7 @@ func (chunk *chunkInfo) patchWithTrailers(trailers *http.Header, ul uploadInfo)
 	if trailerMetachunkHash != "" {
 		chunk.MetachunkHash = trailerMetachunkHash
 		if chunk.MetachunkHash != "" {
-			if !isHexaString(chunk.MetachunkHash, 0) {
+			if !isHexaString(chunk.MetachunkHash, 0, 64) {
 				return errInvalidHeader
 			}
 			chunk.MetachunkHash = strings.ToUpper(chunk.MetachunkHash)

rawx/filerepo.go

@@ -211,7 +211,8 @@ func (fr *fileRepository) linkRelPath(fromPath, toPath string) (linkOperation, e
 			if e0 := syscall.Faccessat(fr.rootFd, fromPath, syscall.F_OK, 0); e0 != nil {
 				return nil, err
 			}
-			if e0 := os.MkdirAll(filepath.Dir(toPath), fr.putMkdirMode); e0 != nil {
+			if e0 := os.MkdirAll(filepath.Dir(filepath.Join(fr.root, toPath)),
+					fr.putMkdirMode); e0 != nil {
 				return nil, err
 			}
 		default:

rawx/handler_chunk.go

@@ -245,11 +245,11 @@ func (rr *rawxRequest) uploadChunk() {
 func (rr *rawxRequest) copyChunk() {
 	var err error
 	if rr.chunk, err = retrieveDestinationHeader(&rr.req.Header, rr.rawx, rr.chunkID); err != nil {
-		rr.replyError("copyChunk()", err)
+		rr.replyError("copyChunk() dest", err)
 		return
 	}
 	if err := rr.chunk.retrieveContentFullpathHeader(&rr.req.Header); err != nil {
-		rr.replyError("copyChunk()", err)
+		rr.replyError("copyChunk() fullpath", err)
 		return
 	}
 
@@ -489,7 +489,9 @@ func (rr *rawxRequest) removeChunk() {
 }
 
 func (rr *rawxRequest) serveChunk() {
-	if !isHexaString(rr.req.URL.Path[1:], 64) {
+	// 24 digits (96 bits) seems reasonable to avoid collisions.
+	// TODO(FVE): make the minimum and maximum configurable
+	if !isHexaString(rr.req.URL.Path[1:], 24, 64) {
 		rr.replyError("", errInvalidChunkID)
 		return
 	}

rawx/utils.go

@@ -46,15 +46,15 @@ func init() {
 	}
 }
 
-func isHexaString(name string, length int) bool {
+func isHexaString(name string, minLen int, maxLen int) bool {
 	var i int
 	var n rune
 	for i, n = range name {
 		if notHexa[byte(n)] {
 			return false
 		}
 	}
-	return length <= 0 || i+1 == length
+	return i+1 >= minLen && i < maxLen
 }
 
 func hasPrefix(s, prefix string) (string, bool) {