nixos/nix
1
1
Fork 0
mirror of https://github.com/NixOS/nix.git synced 2025-11-09 12:06:01 +01:00
Code Activity

Limit to lenient parsing of non-standard URLs only where needed

Browse source 
This allows us to put `parseURL` in more spots without furthering
technical debt.
This commit is contained in:
John Ericson 2025-08-22 12:26:11 -04:00
parent 4083eff0c0
commit 72a548ed6a
8 changed files with 76 additions and 51 deletions
Download patch file Download diff file Expand all files Collapse all files

68
src/libutil/url.cc
View file

@ -108,41 +108,48 @@ static std::string percentEncodeCharSet(std::string_view s, auto charSet)
return res;
}
ParsedURL parseURL(std::string_view url)
ParsedURL parseURL(std::string_view url, bool lenient)
try {
/* Account for several non-standard properties of nix urls (for back-compat):
* - Allow unescaped spaces ' ' and '"' characters in queries.
* - Allow '"', ' ' and '^' characters in the fragment component.
* We could write our own grammar for this, but fixing it up here seems
* more concise, since the deviation is rather minor.
*
* If `!lenient` don't bother initializing, because we can just
* parse `url` directly`.
*/
std::string fixedEncodedUrl = [&]() {
std::string fixed;
std::string_view view = url;
std::string fixedEncodedUrl;
if (auto beforeQuery = splitPrefixTo(view, '?')) {
fixed += *beforeQuery;
fixed += '?';
auto fragmentStart = view.find('#');
auto queryView = view.substr(0, fragmentStart);
auto fixedQuery = percentEncodeCharSet(queryView, extraAllowedCharsInQuery);
fixed += fixedQuery;
view.remove_prefix(std::min(fragmentStart, view.size()));
}
if (lenient) {
fixedEncodedUrl = [&] {
std::string fixed;
std::string_view view = url;
if (auto beforeFragment = splitPrefixTo(view, '#')) {
fixed += *beforeFragment;
fixed += '#';
auto fixedFragment = percentEncodeCharSet(view, extraAllowedCharsInFragment);
fixed += fixedFragment;
if (auto beforeQuery = splitPrefixTo(view, '?')) {
fixed += *beforeQuery;
fixed += '?';
auto fragmentStart = view.find('#');
auto queryView = view.substr(0, fragmentStart);
auto fixedQuery = percentEncodeCharSet(queryView, extraAllowedCharsInQuery);
fixed += fixedQuery;
view.remove_prefix(std::min(fragmentStart, view.size()));
}
if (auto beforeFragment = splitPrefixTo(view, '#')) {
fixed += *beforeFragment;
fixed += '#';
auto fixedFragment = percentEncodeCharSet(view, extraAllowedCharsInFragment);
fixed += fixedFragment;
return fixed;
}
fixed += view;
return fixed;
}
}();
}
fixed += view;
return fixed;
}();
auto urlView = boost::urls::url_view(fixedEncodedUrl);
auto urlView = boost::urls::url_view(lenient ? fixedEncodedUrl : url);
if (!urlView.has_scheme())
throw BadURL("'%s' doesn't have a scheme", url);
@ -179,7 +186,7 @@ try {
.scheme = scheme,
.authority = authority,
.path = path,
.query = decodeQuery(query),
.query = decodeQuery(query, lenient),
.fragment = fragment,
};
} catch (boost::system::system_error & e) {
@ -201,14 +208,17 @@ std::string percentEncode(std::string_view s, std::string_view keep)
s, [keep](char c) { return boost::urls::unreserved_chars(c) || keep.find(c) != keep.npos; });
}
StringMap decodeQuery(std::string_view query)
StringMap decodeQuery(std::string_view query, bool lenient)
try {
/* For back-compat unescaped characters are allowed. */
auto fixedEncodedQuery = percentEncodeCharSet(query, extraAllowedCharsInQuery);
/* When `lenient = true`, for back-compat unescaped characters are allowed. */
std::string fixedEncodedQuery;
if (lenient) {
fixedEncodedQuery = percentEncodeCharSet(query, extraAllowedCharsInQuery);
}
StringMap result;
auto encodedQuery = boost::urls::params_encoded_view(fixedEncodedQuery);
auto encodedQuery = boost::urls::params_encoded_view(lenient ? fixedEncodedQuery : query);
for (auto && [key, value, value_specified] : encodedQuery) {
if (!value_specified) {
warn("dubious URI query '%s' is missing equal sign '%s', ignoring", std::string_view(key), "=");