overleaf/services/web/app/coffee/Features/Project/SafePath.coffee

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# This file is shared between the frontend and server code of web, so that
# filename validation is the same in both implementations.
# Both copies must be kept in sync:
# app/coffee/Features/Project/SafePath.coffee
# public/coffee/ide/directives/SafePath.coffee
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load = () ->
BADCHAR_RX = ///
[
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\/ # no forward slashes
\\ # no back slashes
\* # no asterisk
\u0000-\u001F # no control characters (0-31)
\u007F # no delete
\u0080-\u009F # no unicode control characters (C1)
\uD800-\uDFFF # no unicode surrogate characters
]
///g
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BADFILE_RX = ///
(^\.$) # reject . as a filename
| (^\.\.$) # reject .. as a filename
| (^\s+) # reject leading space
| (\s+$) # reject trailing space
///g
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# Put a block on filenames which match javascript property names, as they
# can cause exceptions where the code puts filenames into a hash. This is a
# temporary workaround until the code in other places is made safe against
# property names.
#
# The list of property names is taken from
# ['prototype'].concat(Object.getOwnPropertyNames(Object.prototype))
BLOCKEDFILE_RX = ///
^(
prototype
|constructor
|toString
|toLocaleString
|valueOf
|hasOwnProperty
|isPrototypeOf
|propertyIsEnumerable
|__defineGetter__
|__lookupGetter__
|__defineSetter__
|__lookupSetter__
|__proto__
)$
///
MAX_PATH = 1024 # Maximum path length, in characters. This is fairly arbitrary.
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SafePath =
clean: (filename) ->
filename = filename.replace BADCHAR_RX, '_'
# for BADFILE_RX replace any matches with an equal number of underscores
filename = filename.replace BADFILE_RX, (match) ->
return new Array(match.length + 1).join("_")
# replace blocked filenames 'prototype' with '@prototype'
filename = filename.replace BLOCKEDFILE_RX, "@$1"
return filename
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isCleanFilename: (filename) ->
return SafePath.isAllowedLength(filename) &&
not filename.match(BADCHAR_RX) &&
not filename.match(BADFILE_RX) &&
not filename.match(BLOCKEDFILE_RX)
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isAllowedLength: (pathname) ->
return pathname.length > 0 && pathname.length <= MAX_PATH
if define?
define [], load
else
module.exports = load()