diff options
| author | Taras Madan <tarasmadan@google.com> | 2025-01-22 16:07:17 +0100 |
|---|---|---|
| committer | Taras Madan <tarasmadan@google.com> | 2025-01-23 10:42:36 +0000 |
| commit | 7b4377ad9d8a7205416df8d6217ef2b010f89481 (patch) | |
| tree | e6fec4fd12ff807a16d847923f501075bf71d16c /vendor/github.com/google/safehtml/url.go | |
| parent | 475a4c203afb8b7d3af51c4fd32bb170ff32a45e (diff) | |
vendor: delete
Diffstat (limited to 'vendor/github.com/google/safehtml/url.go')
| -rw-r--r-- | vendor/github.com/google/safehtml/url.go | 127 |
1 files changed, 0 insertions, 127 deletions
diff --git a/vendor/github.com/google/safehtml/url.go b/vendor/github.com/google/safehtml/url.go deleted file mode 100644 index 6e772219c..000000000 --- a/vendor/github.com/google/safehtml/url.go +++ /dev/null @@ -1,127 +0,0 @@ -// Copyright (c) 2017 The Go Authors. All rights reserved. -// -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file or at -// https://developers.google.com/open-source/licenses/bsd - -package safehtml - -import ( - "regexp" - "strings" -) - -// A URL is an immutable string-like type that is safe to use in URL contexts in -// DOM APIs and HTML documents. -// -// URL guarantees that its value as a string will not cause untrusted script execution -// when evaluated as a hyperlink URL in a browser. -// -// Values of this type are guaranteed to be safe to use in URL/hyperlink contexts, -// such as assignment to URL-valued DOM properties, in the sense that the use -// will not result in a Cross-site Scripting (XSS) vulnerability. Similarly, URLs can -// be interpolated into the URL context of an HTML template (e.g. inside a href attribute). -// However, appropriate HTML-escaping must still be applied. -// -// Note that this type's contract does not imply any guarantees regarding the resource -// the URL refers to. In particular, URLs are not safe to use in a context -// where the referred-to resource is interpreted as trusted code, e.g., as the src of -// a script tag. For safely loading trusted resources, use the TrustedResourceURL type. -type URL struct { - // We declare a URL not as a string but as a struct wrapping a string - // to prevent construction of URL values through string conversion. - str string -} - -// InnocuousURL is an innocuous URL generated by URLSanitized when passed an unsafe URL. -// -// about:invalid is registered in http://www.w3.org/TR/css3-values/#about-invalid, -// and "references a non-existent document with a generic error condition. It can be -// used when a URI is necessary, but the default value shouldn't be resolveable as any -// type of document." -// -// http://tools.ietf.org/html/rfc6694#section-2.1 permits about URLs to contain -// a fragment, which is not to be considered when determining if an about URL is -// well-known. -const InnocuousURL = "about:invalid#zGoSafez" - -// URLSanitized returns a URL whose value is url, validating that the input string matches -// a pattern of commonly used safe URLs. If url fails validation, this method returns a -// URL containing InnocuousURL. -// -// url may be a URL with the http, https, ftp or mailto scheme, or a relative URL, -// i.e. a URL without a scheme. Specifically, a relative URL may be scheme-relative, -// absolute-path-relative, or path-relative. See -// http://url.spec.whatwg.org/#concept-relative-url. -// -// url may also be a base64 data URL with an allowed audio, image or video MIME type. -// -// No attempt is made at validating that the URL percent-decodes to structurally valid or -// interchange-valid UTF-8 since the percent-decoded representation is unsafe to use in an -// HTML context regardless of UTF-8 validity. -func URLSanitized(url string) URL { - if !isSafeURL(url) { - return URL{InnocuousURL} - } - return URL{url} -} - -// safeURLPattern matches URLs that -// (a) Start with a scheme in an allowlist (http, https, mailto, ftp); or -// (b) Contain no scheme. To ensure that the URL cannot be interpreted as a -// disallowed scheme URL, ':' may only appear after one of the runes [/?#]. -// -// The origin (RFC 6454) in which a URL is loaded depends on -// its scheme. We assume that the scheme used by the current document is HTTPS, HTTP, or -// something equivalent. We allow relative URLs unless in a particularly sensitive context -// called a "TrustedResourceUrl" context. In a non-TrustedResourceURL context we allow absolute -// URLs whose scheme is on a white-list. -// -// The position of the first colon (':') character determines whether a URL is absolute or relative. -// Looking at the prefix leading up to the first colon allows us to identify relative and absolute URLs, -// extract the scheme, and minimize the risk of a user-agent concluding a URL specifies a scheme not in -// our allowlist. -// -// According to RFC 3986 Section 3, the normative interpretation of the canonicial WHATWG specification -// (https://url.spec.whatwg.org/#url-scheme-string), colons can appear in a URL in these locations: -// * A colon after a non-empty run of (ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )) ends a scheme. -// If the colon after the scheme is not followed by "//" then any subsequent colons are part -// of an opaque URI body. -// * Otherwise, a colon after a hash (#) must be in the fragment. -// * Otherwise, a colon after a (?) must be in the query. -// * Otherwise, a colon after a single solidus ("/") must be in the path. -// * Otherwise, a colon after a double solidus ("//") must be in the authority (before port). -// * Otherwise, a colon after a valid protocol must be in the opaque part of the URL. -var safeURLPattern = regexp.MustCompile(`^(?:(?:https?|mailto|ftp):|[^:/?#]*(?:[/?#]|$))`) - -// dataURLPattern matches base-64 data URLs (RFC 2397), with the first capture group being the media type -// specification given as a MIME type. -// -// Note: this pattern does not match data URLs containig media type specifications with optional parameters, -// such as `data:text/javascript;charset=UTF-8;base64,...`. This is ok since this pattern only needs to -// match audio, image and video MIME types in its capture group. -var dataURLPattern = regexp.MustCompile(`^data:([^;,]*);base64,[a-z0-9+/]+=*$`) - -// safeMIMETypePattern matches MIME types that are safe to include in a data URL. -var safeMIMETypePattern = regexp.MustCompile(`^(?:audio/(?:3gpp2|3gpp|aac|midi|mp3|mp4|mpeg|oga|ogg|opus|x-m4a|x-matroska|x-wav|wav|webm)|image/(?:bmp|gif|jpeg|jpg|png|tiff|webp|x-icon)|video/(?:mpeg|mp4|ogg|webm|x-matroska))$`) - -// isSafeURL matches url to a subset of URLs that will not cause script execution if used in -// a URL context within a HTML document. Specifically, this method returns true if url: -// (a) Starts with a scheme in the default allowlist (http, https, mailto, ftp); or -// (b) Contains no scheme. To ensure that the URL cannot be interpreted as a -// disallowed scheme URL, the runes ':', and '&' may only appear -// after one of the runes [/?#]. -func isSafeURL(url string) bool { - // Ignore case. - url = strings.ToLower(url) - if safeURLPattern.MatchString(url) { - return true - } - submatches := dataURLPattern.FindStringSubmatch(url) - return len(submatches) == 2 && safeMIMETypePattern.MatchString(submatches[1]) -} - -// String returns the string form of the URL. -func (u URL) String() string { - return u.str -} |
