lfs: ensure the transfer request is for a known URI

Since the dispatching code only checks the beginning of the string, this
enforces that there's only one more path component.

hgext/lfs/wireprotolfsserver.py

@@ -1,286 +1,291
 # wireprotolfsserver.py - lfs protocol server side implementation
 #
 # Copyright 2018 Matt Harbison <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import datetime
 import errno
 import json
 
 from mercurial.hgweb import (
     common as hgwebcommon,
 )
 
 from mercurial import (
     pycompat,
 )
 
 HTTP_OK = hgwebcommon.HTTP_OK
 HTTP_CREATED = hgwebcommon.HTTP_CREATED
 HTTP_BAD_REQUEST = hgwebcommon.HTTP_BAD_REQUEST
+HTTP_NOT_FOUND = hgwebcommon.HTTP_NOT_FOUND
 
 def handlewsgirequest(orig, rctx, req, res, checkperm):
     """Wrap wireprotoserver.handlewsgirequest() to possibly process an LFS
     request if it is left unprocessed by the wrapped method.
     """
     if orig(rctx, req, res, checkperm):
         return True
 
     if not rctx.repo.ui.configbool('experimental', 'lfs.serve'):
         return False
 
     if not req.dispatchpath:
         return False
 
     try:
         if req.dispatchpath == b'.git/info/lfs/objects/batch':
             checkperm(rctx, req, 'pull')
             return _processbatchrequest(rctx.repo, req, res)
         # TODO: reserve and use a path in the proposed http wireprotocol /api/
         #       namespace?
         elif req.dispatchpath.startswith(b'.hg/lfs/objects'):
             return _processbasictransfer(rctx.repo, req, res,
                                          lambda perm:
                                                 checkperm(rctx, req, perm))
         return False
     except hgwebcommon.ErrorResponse as e:
         # XXX: copied from the handler surrounding wireprotoserver._callhttp()
         #      in the wrapped function.  Should this be moved back to hgweb to
         #      be a common handler?
         for k, v in e.headers:
             res.headers[k] = v
         res.status = hgwebcommon.statusmessage(e.code, pycompat.bytestr(e))
         res.setbodybytes(b'0\n%s\n' % pycompat.bytestr(e))
         return True
 
 def _sethttperror(res, code, message=None):
     res.status = hgwebcommon.statusmessage(code, message=message)
     res.headers[b'Content-Type'] = b'text/plain; charset=utf-8'
     res.setbodybytes(b'')
 
 def _processbatchrequest(repo, req, res):
     """Handle a request for the Batch API, which is the gateway to granting file
     access.
 
     https://github.com/git-lfs/git-lfs/blob/master/docs/api/batch.md
     """
 
     # Mercurial client request:
     #
     #   HOST: localhost:$HGPORT
     #   ACCEPT: application/vnd.git-lfs+json
     #   ACCEPT-ENCODING: identity
     #   USER-AGENT: git-lfs/2.3.4 (Mercurial 4.5.2+1114-f48b9754f04c+20180316)
     #   Content-Length: 125
     #   Content-Type: application/vnd.git-lfs+json
     #
     #   {
     #     "objects": [
     #       {
     #         "oid": "31cf...8e5b"
     #         "size": 12
     #       }
     #     ]
     #     "operation": "upload"
     #  }
 
     if (req.method != b'POST'
         or req.headers[b'Content-Type'] != b'application/vnd.git-lfs+json'
         or req.headers[b'Accept'] != b'application/vnd.git-lfs+json'):
         # TODO: figure out what the proper handling for a bad request to the
         #       Batch API is.
         _sethttperror(res, HTTP_BAD_REQUEST, b'Invalid Batch API request')
         return True
 
     # XXX: specify an encoding?
     lfsreq = json.loads(req.bodyfh.read())
 
     # If no transfer handlers are explicitly requested, 'basic' is assumed.
     if 'basic' not in lfsreq.get('transfers', ['basic']):
         _sethttperror(res, HTTP_BAD_REQUEST,
                       b'Only the basic LFS transfer handler is supported')
         return True
 
     operation = lfsreq.get('operation')
     if operation not in ('upload', 'download'):
         _sethttperror(res, HTTP_BAD_REQUEST,
                       b'Unsupported LFS transfer operation: %s' % operation)
         return True
 
     localstore = repo.svfs.lfslocalblobstore
 
     objects = [p for p in _batchresponseobjects(req, lfsreq.get('objects', []),
                                                 operation, localstore)]
 
     rsp = {
         'transfer': 'basic',
         'objects': objects,
     }
 
     res.status = hgwebcommon.statusmessage(HTTP_OK)
     res.headers[b'Content-Type'] = b'application/vnd.git-lfs+json'
     res.setbodybytes(pycompat.bytestr(json.dumps(rsp)))
 
     return True
 
 def _batchresponseobjects(req, objects, action, store):
     """Yield one dictionary of attributes for the Batch API response for each
     object in the list.
 
     req: The parsedrequest for the Batch API request
     objects: The list of objects in the Batch API object request list
     action: 'upload' or 'download'
     store: The local blob store for servicing requests"""
 
     # Successful lfs-test-server response to solict an upload:
     # {
     #    u'objects': [{
     #       u'size': 12,
     #       u'oid': u'31cf...8e5b',
     #       u'actions': {
     #           u'upload': {
     #               u'href': u'http://localhost:$HGPORT/objects/31cf...8e5b',
     #               u'expires_at': u'0001-01-01T00:00:00Z',
     #               u'header': {
     #                   u'Accept': u'application/vnd.git-lfs'
     #               }
     #           }
     #       }
     #    }]
     # }
 
     # TODO: Sort out the expires_at/expires_in/authenticated keys.
 
     for obj in objects:
         # Convert unicode to ASCII to create a filesystem path
         oid = obj.get('oid').encode('ascii')
         rsp = {
             'oid': oid,
             'size': obj.get('size'),  # XXX: should this check the local size?
             #'authenticated': True,
         }
 
         exists = True
         verifies = False
 
         # Verify an existing file on the upload request, so that the client is
         # solicited to re-upload if it corrupt locally.  Download requests are
         # also verified, so the error can be flagged in the Batch API response.
         # (Maybe we can use this to short circuit the download for `hg verify`,
         # IFF the client can assert that the remote end is an hg server.)
         # Otherwise, it's potentially overkill on download, since it is also
         # verified as the file is streamed to the caller.
         try:
             verifies = store.verify(oid)
         except IOError as inst:
             if inst.errno != errno.ENOENT:
                 rsp['error'] = {
                     'code': 500,
                     'message': inst.strerror or 'Internal Server Server'
                 }
                 yield rsp
                 continue
 
             exists = False
 
         # Items are always listed for downloads.  They are dropped for uploads
         # IFF they already exist locally.
         if action == 'download':
             if not exists:
                 rsp['error'] = {
                     'code': 404,
                     'message': "The object does not exist"
                 }
                 yield rsp
                 continue
 
             elif not verifies:
                 rsp['error'] = {
                     'code': 422,   # XXX: is this the right code?
                     'message': "The object is corrupt"
                 }
                 yield rsp
                 continue
 
         elif verifies:
             yield rsp  # Skip 'actions': already uploaded
             continue
 
         expiresat = datetime.datetime.now() + datetime.timedelta(minutes=10)
 
         rsp['actions'] = {
             '%s' % action: {
                 # TODO: Account for the --prefix, if any.
                 'href': '%s/.hg/lfs/objects/%s' % (req.baseurl, oid),
                 # datetime.isoformat() doesn't include the 'Z' suffix
                 "expires_at": expiresat.strftime('%Y-%m-%dT%H:%M:%SZ'),
                 'header': {
                     # The spec doesn't mention the Accept header here, but avoid
                     # a gratuitous deviation from lfs-test-server in the test
                     # output.
                     'Accept': 'application/vnd.git-lfs'
                 }
             }
         }
 
         yield rsp
 
 def _processbasictransfer(repo, req, res, checkperm):
     """Handle a single file upload (PUT) or download (GET) action for the Basic
     Transfer Adapter.
 
     After determining if the request is for an upload or download, the access
     must be checked by calling ``checkperm()`` with either 'pull' or 'upload'
     before accessing the files.
 
     https://github.com/git-lfs/git-lfs/blob/master/docs/api/basic-transfers.md
     """
 
     method = req.method
     oid = req.dispatchparts[-1]
     localstore = repo.svfs.lfslocalblobstore
 
+    if len(req.dispatchparts) != 4:
+        _sethttperror(res, HTTP_NOT_FOUND)
+        return True
+
     if method == b'PUT':
         checkperm('upload')
 
         # TODO: verify Content-Type?
 
         existed = localstore.has(oid)
 
         # TODO: how to handle timeouts?  The body proxy handles limiting to
         #       Content-Length, but what happens if a client sends less than it
         #       says it will?
 
         # TODO: download() will abort if the checksum fails.  It should raise
         #       something checksum specific that can be caught here, and turned
         #       into an http code.
         localstore.download(oid, req.bodyfh)
 
         statusmessage = hgwebcommon.statusmessage
         res.status = statusmessage(HTTP_OK if existed else HTTP_CREATED)
 
         # There's no payload here, but this is the header that lfs-test-server
         # sends back.  This eliminates some gratuitous test output conditionals.
         res.headers[b'Content-Type'] = b'text/plain; charset=utf-8'
         res.setbodybytes(b'')
 
         return True
     elif method == b'GET':
         checkperm('pull')
 
         res.status = hgwebcommon.statusmessage(HTTP_OK)
         res.headers[b'Content-Type'] = b'application/octet-stream'
 
         # TODO: figure out how to send back the file in chunks, instead of
         #       reading the whole thing.
         res.setbodybytes(localstore.read(oid))
 
         return True
     else:
         _sethttperror(res, HTTP_BAD_REQUEST,
                       message=b'Unsupported LFS transfer method: %s' % method)
         return True