1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
// Copyright (c) 2020-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <httpserver.h>
#include <netaddress.h>
#include <test/fuzz/FuzzedDataProvider.h>
#include <test/fuzz/fuzz.h>
#include <test/fuzz/util.h>
#include <util/strencodings.h>
#include <event2/buffer.h>
#include <event2/event.h>
#include <event2/http.h>
#include <event2/http_struct.h>
#include <cassert>
#include <cstdint>
#include <string>
#include <vector>
extern "C" int evhttp_parse_firstline_(struct evhttp_request*, struct evbuffer*);
extern "C" int evhttp_parse_headers_(struct evhttp_request*, struct evbuffer*);
std::string RequestMethodString(HTTPRequest::RequestMethod m);
FUZZ_TARGET(http_request)
{
FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
evhttp_request* evreq = evhttp_request_new(nullptr, nullptr);
assert(evreq != nullptr);
evreq->kind = EVHTTP_REQUEST;
evbuffer* evbuf = evbuffer_new();
assert(evbuf != nullptr);
const std::vector<uint8_t> http_buffer = ConsumeRandomLengthByteVector(fuzzed_data_provider, 4096);
evbuffer_add(evbuf, http_buffer.data(), http_buffer.size());
// Avoid constructing requests that will be interpreted by libevent as PROXY requests to avoid triggering
// a nullptr dereference. The dereference (req->evcon->http_server) takes place in evhttp_parse_request_line
// and is a consequence of our hacky but necessary use of the internal function evhttp_parse_firstline_ in
// this fuzzing harness. The workaround is not aesthetically pleasing, but it successfully avoids the troublesome
// code path. " http:// HTTP/1.1\n" was a crashing input prior to this workaround.
const std::string http_buffer_str = ToLower(std::string{http_buffer.begin(), http_buffer.end()});
if (http_buffer_str.find(" http://") != std::string::npos || http_buffer_str.find(" https://") != std::string::npos ||
evhttp_parse_firstline_(evreq, evbuf) != 1 || evhttp_parse_headers_(evreq, evbuf) != 1) {
evbuffer_free(evbuf);
evhttp_request_free(evreq);
return;
}
HTTPRequest http_request{evreq, true};
const HTTPRequest::RequestMethod request_method = http_request.GetRequestMethod();
(void)RequestMethodString(request_method);
(void)http_request.GetURI();
(void)http_request.GetHeader("Host");
const std::string header = fuzzed_data_provider.ConsumeRandomLengthString(16);
(void)http_request.GetHeader(header);
(void)http_request.WriteHeader(header, fuzzed_data_provider.ConsumeRandomLengthString(16));
(void)http_request.GetHeader(header);
const std::string body = http_request.ReadBody();
assert(body.empty());
const CService service = http_request.GetPeer();
assert(service.ToStringAddrPort() == "[::]:0");
evbuffer_free(evbuf);
evhttp_request_free(evreq);
}
|
