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Fix/migl/162 #178

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Fix/migl/162 #178

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b31732c
Connection.cpp: Fix directory traversal bug #162
linkjumper Sep 19, 2022
5e7d92c
Connection.cpp: Forbid empty static root path
linkjumper Sep 21, 2022
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6 changes: 6 additions & 0 deletions src/main/c/Connection.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -867,6 +867,9 @@ bool Connection::processHeaders(uint8_t* first, uint8_t* last) {
if (requestUri == nullptr) {
return sendBadRequest("Malformed request line");
}
if (std::string(requestUri).find("..") != std::string::npos) {
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Is it safe to assume an URL shouldn't contain any ..? Eg. a/b/c/../d seems ok to me.

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Do you mean something like that?

std::string merge_uri(std::string & uri) {
    std::istringstream is_uri {uri};
    std::vector<std::string> v;
    std::string parsed_uri;

    for (std::string line; std::getline(is_uri, line, '/'); ) {
        if(line == ".") {
            continue;    
        } if(line == "..") {
            if(!v.empty()) {
                v.pop_back();
            }
        } else if(line != "") {
            line = "/" + line;
            v.push_back(line);
        }
    }

    for (auto const & dir : v){
        parsed_uri += dir;
    }

    return parsed_uri.empty() ? "/" : parsed_uri;
}

For comparison, nginx has your described behavior. e.g. a/b/c/../d becomes a/b/d . But one must also say, nginx has a complex state machine that not only protects against directory triversal, but can also handle all other special characters. If that's what we want, I'd at least like to take commit 5e7d92c and drop the other one.

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Indeed, the empty root path fix is fine to merge 👍

I'd say the path traversal needs some more work. Maybe std filesystem / path could get handy here?

return sendBadRequest("Malformed uri");
}

const char* httpVersion = shift(requestLine);
if (httpVersion == nullptr) {
Expand Down Expand Up @@ -1197,6 +1200,9 @@ std::list<Connection::Range> Connection::processRangesForStaticData(const std::l
#endif
bool Connection::sendStaticData() {
// TODO: fold this into the handler way of doing things.
if (_server.getStaticPath().empty()) {
return send404();
}
std::string path = _server.getStaticPath() + getRequestUri();
auto rangeHeader = getHeader("Range");
// Trim any trailing queries.
Expand Down