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fix PW-001: Incorrect Hostname Parsing in pw::URLInfo::parse Leads to Denial of Service #2

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fix PW-001: Incorrect Hostname Parsing in pw::URLInfo::parse Leads to Denial of Service #2

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78 changes: 52 additions & 26 deletions polyweb.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -310,55 +310,81 @@ namespace pw {

int URLInfo::parse(pn::StringView url) {
size_t offset = 0;

size_t scheme_host_delimiter_pos;
if ((scheme_host_delimiter_pos = url.find("://", offset)) == std::string::npos || scheme_host_delimiter_pos == offset) {
detail::set_last_error(PW_EWEB);
return PN_ERROR;
}
scheme = url.substr(offset, scheme_host_delimiter_pos - offset);
offset = scheme_host_delimiter_pos + 3;

credentials.clear();
size_t credentials_host_delimiter_pos;
if ((credentials_host_delimiter_pos = url.find('@', offset)) != std::string::npos &&
url.find('/', offset) > credentials_host_delimiter_pos) {
url.find_first_of("/?#", offset) > credentials_host_delimiter_pos) {
if (credentials_host_delimiter_pos == offset) {
detail::set_last_error(PW_EWEB);
return PN_ERROR;
}
credentials = percent_decode(url.substr(offset, credentials_host_delimiter_pos - offset));
offset = credentials_host_delimiter_pos + 1;
}

size_t path_pos;
if ((path_pos = url.find('/', offset)) != std::string::npos) {
if (path_pos == offset) {
detail::set_last_error(PW_EWEB);
return PN_ERROR;
}
host = url.substr(offset, path_pos - offset);
offset = path_pos + 1;
} else {

// Find the end of the authority part (host and port)
size_t authority_terminator_pos = url.find_first_of("/?#", offset);

if (authority_terminator_pos == std::string::npos) {
// Case: scheme://host
host = url.substr(offset);
path = '/';
return PN_OK;
}

size_t path_query_string_delimiter_pos;
if ((path_query_string_delimiter_pos = url.find('?', offset)) != std::string::npos) {
if (path_query_string_delimiter_pos == offset) {
query_parameters->clear();
} else {
// Case: scheme://host/... or scheme://host?... or scheme://host#...
host = url.substr(offset, authority_terminator_pos - offset);
offset = authority_terminator_pos;

// Now parse path and query from the new offset
if (url[offset] == '/') {
// Path is present
size_t path_terminator_pos = url.find_first_of("?#", offset);
if (path_terminator_pos == std::string::npos) {
// Path is the rest of the string
path = url.substr(offset);
query_parameters->clear();
} else {
// Path is up to the '?' or '#'
path = url.substr(offset, path_terminator_pos - offset);
offset = path_terminator_pos;
}
} else {
// No path component, e.g., "https://example.com?q=1"
path = '/';
}

// Parse query if it exists
if (offset != std::string::npos && url[offset] == '?') {
offset++; // Move past '?'
size_t fragment_pos = url.find('#', offset);
if (fragment_pos == std::string::npos) {
query_parameters.parse(url.substr(offset));
} else {
query_parameters.parse(url.substr(offset, fragment_pos - offset));
}
} else {
path = '/' + url.substr(offset, path_query_string_delimiter_pos - offset);
query_parameters->clear();
}
offset = path_query_string_delimiter_pos + 1;
} else {
path = '/' + url.substr(offset, url.find('#', offset));
return PN_OK;
}

query_parameters.parse(url.substr(offset, url.find('#', offset)));

if (host.empty()) {
detail::set_last_error(PW_EWEB);
return PN_ERROR;
}
// A path must always exist, even if it's just "/"
if (path.empty()) {
path = "/";
}

return PN_OK;
}

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