Mercurial > hg
view mercurial/diffutil.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 | be441eb65f09 |
children | 78b270a55dc6 |
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# diffutil.py - utility functions related to diff and patch # # Copyright 2006 Brendan Cully <brendan@kublai.com> # Copyright 2007 Chris Mason <chris.mason@oracle.com> # Copyright 2018 Octobus <octobus@octobus.net> # # 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 from .i18n import _ from . import ( mdiff, pycompat, ) def diffallopts(ui, opts=None, untrusted=False, section='diff'): '''return diffopts with all features supported and parsed''' return difffeatureopts(ui, opts=opts, untrusted=untrusted, section=section, git=True, whitespace=True, formatchanging=True) def difffeatureopts(ui, opts=None, untrusted=False, section='diff', git=False, whitespace=False, formatchanging=False): '''return diffopts with only opted-in features parsed Features: - git: git-style diffs - whitespace: whitespace options like ignoreblanklines and ignorews - formatchanging: options that will likely break or cause correctness issues with most diff parsers ''' def get(key, name=None, getter=ui.configbool, forceplain=None): if opts: v = opts.get(key) # diffopts flags are either None-default (which is passed # through unchanged, so we can identify unset values), or # some other falsey default (eg --unified, which defaults # to an empty string). We only want to override the config # entries from hgrc with command line values if they # appear to have been set, which is any truthy value, # True, or False. if v or isinstance(v, bool): return v if forceplain is not None and ui.plain(): return forceplain return getter(section, name or key, untrusted=untrusted) # core options, expected to be understood by every diff parser buildopts = { 'nodates': get('nodates'), 'showfunc': get('show_function', 'showfunc'), 'context': get('unified', getter=ui.config), } buildopts['xdiff'] = ui.configbool('experimental', 'xdiff') if git: buildopts['git'] = get('git') # since this is in the experimental section, we need to call # ui.configbool directory buildopts['showsimilarity'] = ui.configbool('experimental', 'extendedheader.similarity') # need to inspect the ui object instead of using get() since we want to # test for an int hconf = ui.config('experimental', 'extendedheader.index') if hconf is not None: hlen = None try: # the hash config could be an integer (for length of hash) or a # word (e.g. short, full, none) hlen = int(hconf) if hlen < 0 or hlen > 40: msg = _("invalid length for extendedheader.index: '%d'\n") ui.warn(msg % hlen) except ValueError: # default value if hconf == 'short' or hconf == '': hlen = 12 elif hconf == 'full': hlen = 40 elif hconf != 'none': msg = _("invalid value for extendedheader.index: '%s'\n") ui.warn(msg % hconf) finally: buildopts['index'] = hlen if whitespace: buildopts['ignorews'] = get('ignore_all_space', 'ignorews') buildopts['ignorewsamount'] = get('ignore_space_change', 'ignorewsamount') buildopts['ignoreblanklines'] = get('ignore_blank_lines', 'ignoreblanklines') buildopts['ignorewseol'] = get('ignore_space_at_eol', 'ignorewseol') if formatchanging: buildopts['text'] = opts and opts.get('text') binary = None if opts is None else opts.get('binary') buildopts['nobinary'] = (not binary if binary is not None else get('nobinary', forceplain=False)) buildopts['noprefix'] = get('noprefix', forceplain=False) buildopts['worddiff'] = get('word_diff', 'word-diff', forceplain=False) return mdiff.diffopts(**pycompat.strkwargs(buildopts))