Mercurial > hg
view mercurial/hgweb/wsgicgi.py @ 40626:87a872555e90
revlog: detect incomplete revlog reads
_readsegment() is supposed to return N bytes of revlog revision
data starting at a file offset. Surprisingly, its behavior before
this patch never verified that it actually read and returned N
bytes! Instead, it would perform the read(), then return whatever
data was available. And even more surprisingly, nothing in the
call chain appears to have been validating that it received all
the data it was expecting.
This behavior could lead to partial or incomplete revision chunks
being operated on. This could result in e.g. cached deltas being
applied against incomplete base revisions. The delta application
process would happily perform this operation. Only hash
verification would detect the corruption and save us.
This commit changes the behavior of raw revlog reading to validate
that we actually read() the number of bytes that were requested.
We will raise a more specific error faster, rather than possibly
have it go undetected or manifest later in the call stack, at
delta application or hash verification.
Differential Revision: https://phab.mercurial-scm.org/D5266
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 13 Nov 2018 12:30:59 -0800 |
parents | 2d5b5bcc3b9f |
children | 2372284d9457 |
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# hgweb/wsgicgi.py - CGI->WSGI translator # # Copyright 2006 Eric Hopper <hopper@omnifarious.org> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. # # This was originally copied from the public domain code at # http://www.python.org/dev/peps/pep-0333/#the-server-gateway-side from __future__ import absolute_import import os from .. import ( pycompat, ) from ..utils import ( procutil, ) from . import ( common, ) def launch(application): procutil.setbinary(procutil.stdin) procutil.setbinary(procutil.stdout) environ = dict(os.environ.iteritems()) # re-exports environ.setdefault(r'PATH_INFO', '') if environ.get(r'SERVER_SOFTWARE', r'').startswith(r'Microsoft-IIS'): # IIS includes script_name in PATH_INFO scriptname = environ[r'SCRIPT_NAME'] if environ[r'PATH_INFO'].startswith(scriptname): environ[r'PATH_INFO'] = environ[r'PATH_INFO'][len(scriptname):] stdin = procutil.stdin if environ.get(r'HTTP_EXPECT', r'').lower() == r'100-continue': stdin = common.continuereader(stdin, procutil.stdout.write) environ[r'wsgi.input'] = stdin environ[r'wsgi.errors'] = procutil.stderr environ[r'wsgi.version'] = (1, 0) environ[r'wsgi.multithread'] = False environ[r'wsgi.multiprocess'] = True environ[r'wsgi.run_once'] = True if environ.get(r'HTTPS', r'off').lower() in (r'on', r'1', r'yes'): environ[r'wsgi.url_scheme'] = r'https' else: environ[r'wsgi.url_scheme'] = r'http' headers_set = [] headers_sent = [] out = procutil.stdout def write(data): if not headers_set: raise AssertionError("write() before start_response()") elif not headers_sent: # Before the first output, send the stored headers status, response_headers = headers_sent[:] = headers_set out.write('Status: %s\r\n' % pycompat.bytesurl(status)) for hk, hv in response_headers: out.write('%s: %s\r\n' % (pycompat.bytesurl(hk), pycompat.bytesurl(hv))) out.write('\r\n') out.write(data) out.flush() def start_response(status, response_headers, exc_info=None): if exc_info: try: if headers_sent: # Re-raise original exception if headers sent raise exc_info[0](exc_info[1], exc_info[2]) finally: exc_info = None # avoid dangling circular ref elif headers_set: raise AssertionError("Headers already set!") headers_set[:] = [status, response_headers] return write content = application(environ, start_response) try: for chunk in content: write(chunk) if not headers_sent: write('') # send headers now if body was empty finally: getattr(content, 'close', lambda: None)()