From 7d5c99d09f6743b055d53fc3f642746d9801479b Mon Sep 17 00:00:00 2001 From: Fedor Indutny Date: Mon, 3 Feb 2020 21:10:35 +0100 Subject: [PATCH] Support multi-coding Transfer-Encoding `Transfer-Encoding` header might have multiple codings in it. Even though llhttp cares only about `chunked`, it must check that `chunked` is the last coding (if present). ABNF from RFC 7230: ``` Transfer-Encoding = *( "," OWS ) transfer-coding *( OWS "," [ OWS transfer-coding ] ) transfer-coding = "chunked" / "compress" / "deflate" / "gzip" / transfer-extension transfer-extension = token *( OWS ";" OWS transfer-parameter ) transfer-parameter = token BWS "=" BWS ( token / quoted-string ) ``` However, if `chunked` is not last - llhttp must assume that the encoding and size of the body is unknown (according to 3.3.3 of RFC 7230) and read the response until EOF. For request - the error must be raised for an unknown `Transfer-Encoding`. Furthermore, 3.3.3 of RFC 7230 explicitly states that presence of both `Transfer-Encoding` and `Content-Length` indicates the smuggling attack and "ought to be handled as an error". For the lenient mode: * Unknown `Transfer-Encoding` in requests is not an error and request body is simply read until EOF (end of connection) * Only `Transfer-Encoding: chunked` together with `Content-Length` would result an error (just like before the patch) PR-URL: https://github.com/nodejs-private/http-parser-private/pull/4 Reviewed-By: Matteo Collina Reviewed-By: Sam Roberts Reviewed-By: James M Snell --- http_parser.c | 85 ++++++++++++++++++++++++++++++++++++++++++------ http_parser.h | 5 ++- test.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++--- 3 files changed, 165 insertions(+), 14 deletions(-) diff --git a/http_parser.c b/http_parser.c index 4896385..0f76b6a 100644 --- a/http_parser.c +++ b/http_parser.c @@ -381,7 +381,10 @@ enum header_states , h_transfer_encoding , h_upgrade + , h_matching_transfer_encoding_token_start , h_matching_transfer_encoding_chunked + , h_matching_transfer_encoding_token + , h_matching_connection_token_start , h_matching_connection_keep_alive , h_matching_connection_close @@ -1335,6 +1338,7 @@ reexecute: parser->header_state = h_general; } else if (parser->index == sizeof(TRANSFER_ENCODING)-2) { parser->header_state = h_transfer_encoding; + parser->flags |= F_TRANSFER_ENCODING; } break; @@ -1416,10 +1420,14 @@ reexecute: if ('c' == c) { parser->header_state = h_matching_transfer_encoding_chunked; } else { - parser->header_state = h_general; + parser->header_state = h_matching_transfer_encoding_token; } break; + /* Multi-value `Transfer-Encoding` header */ + case h_matching_transfer_encoding_token_start: + break; + case h_content_length: if (UNLIKELY(!IS_NUM(ch))) { SET_ERRNO(HPE_INVALID_CONTENT_LENGTH); @@ -1563,16 +1571,41 @@ reexecute: goto error; /* Transfer-Encoding: chunked */ + case h_matching_transfer_encoding_token_start: + /* looking for 'Transfer-Encoding: chunked' */ + if ('c' == c) { + h_state = h_matching_transfer_encoding_chunked; + } else if (STRICT_TOKEN(c)) { + /* TODO(indutny): similar code below does this, but why? + * At the very least it seems to be inconsistent given that + * h_matching_transfer_encoding_token does not check for + * `STRICT_TOKEN` + */ + h_state = h_matching_transfer_encoding_token; + } else if (c == ' ' || c == '\t') { + /* Skip lws */ + } else { + h_state = h_general; + } + break; + case h_matching_transfer_encoding_chunked: parser->index++; if (parser->index > sizeof(CHUNKED)-1 || c != CHUNKED[parser->index]) { - h_state = h_general; + h_state = h_matching_transfer_encoding_token; } else if (parser->index == sizeof(CHUNKED)-2) { h_state = h_transfer_encoding_chunked; } break; + case h_matching_transfer_encoding_token: + if (ch == ',') { + h_state = h_matching_transfer_encoding_token_start; + parser->index = 0; + } + break; + case h_matching_connection_token_start: /* looking for 'Connection: keep-alive' */ if (c == 'k') { @@ -1631,7 +1664,7 @@ reexecute: break; case h_transfer_encoding_chunked: - if (ch != ' ') h_state = h_general; + if (ch != ' ') h_state = h_matching_transfer_encoding_token; break; case h_connection_keep_alive: @@ -1765,12 +1798,17 @@ reexecute: REEXECUTE(); } - /* Cannot use chunked encoding and a content-length header together - per the HTTP specification. */ - if ((parser->flags & F_CHUNKED) && + /* Cannot us transfer-encoding and a content-length header together + per the HTTP specification. (RFC 7230 Section 3.3.3) */ + if ((parser->flags & F_TRANSFER_ENCODING) && (parser->flags & F_CONTENTLENGTH)) { - SET_ERRNO(HPE_UNEXPECTED_CONTENT_LENGTH); - goto error; + /* Allow it for lenient parsing as long as `Transfer-Encoding` is + * not `chunked` + */ + if (!lenient || (parser->flags & F_CHUNKED)) { + SET_ERRNO(HPE_UNEXPECTED_CONTENT_LENGTH); + goto error; + } } UPDATE_STATE(s_headers_done); @@ -1845,8 +1883,31 @@ reexecute: UPDATE_STATE(NEW_MESSAGE()); CALLBACK_NOTIFY(message_complete); } else if (parser->flags & F_CHUNKED) { - /* chunked encoding - ignore Content-Length header */ + /* chunked encoding - ignore Content-Length header, + * prepare for a chunk */ UPDATE_STATE(s_chunk_size_start); + } else if (parser->flags & F_TRANSFER_ENCODING) { + if (parser->type == HTTP_REQUEST && !lenient) { + /* RFC 7230 3.3.3 */ + + /* If a Transfer-Encoding header field + * is present in a request and the chunked transfer coding is not + * the final encoding, the message body length cannot be determined + * reliably; the server MUST respond with the 400 (Bad Request) + * status code and then close the connection. + */ + SET_ERRNO(HPE_INVALID_TRANSFER_ENCODING); + RETURN(p - data); /* Error */ + } else { + /* RFC 7230 3.3.3 */ + + /* If a Transfer-Encoding header field is present in a response and + * the chunked transfer coding is not the final encoding, the + * message body length is determined by reading the connection until + * it is closed by the server. + */ + UPDATE_STATE(s_body_identity_eof); + } } else { if (parser->content_length == 0) { /* Content-Length header given but zero: Content-Length: 0\r\n */ @@ -2100,6 +2161,12 @@ http_message_needs_eof (const http_parser *parser) return 0; } + /* RFC 7230 3.3.3, see `s_headers_almost_done` */ + if ((parser->flags & F_TRANSFER_ENCODING) && + (parser->flags & F_CHUNKED) == 0) { + return 1; + } + if ((parser->flags & F_CHUNKED) || parser->content_length != ULLONG_MAX) { return 0; } diff --git a/http_parser.h b/http_parser.h index 16b5281..4f840c2 100644 --- a/http_parser.h +++ b/http_parser.h @@ -225,6 +225,7 @@ enum flags , F_UPGRADE = 1 << 5 , F_SKIPBODY = 1 << 6 , F_CONTENTLENGTH = 1 << 7 + , F_TRANSFER_ENCODING = 1 << 8 }; @@ -271,6 +272,8 @@ enum flags "unexpected content-length header") \ XX(INVALID_CHUNK_SIZE, \ "invalid character in chunk size header") \ + XX(INVALID_TRANSFER_ENCODING, \ + "request has invalid transfer-encoding") \ XX(INVALID_CONSTANT, "invalid constant string") \ XX(INVALID_INTERNAL_STATE, "encountered unexpected internal state")\ XX(STRICT, "strict mode assertion failed") \ @@ -293,11 +296,11 @@ enum http_errno { struct http_parser { /** PRIVATE **/ unsigned int type : 2; /* enum http_parser_type */ - unsigned int flags : 8; /* F_* values from 'flags' enum; semi-public */ unsigned int state : 7; /* enum state from http_parser.c */ unsigned int header_state : 7; /* enum header_state from http_parser.c */ unsigned int index : 7; /* index into current matcher */ unsigned int lenient_http_headers : 1; + unsigned int flags : 16; /* F_* values from 'flags' enum; semi-public */ uint32_t nread; /* # bytes read in various scenarios */ uint64_t content_length; /* # bytes in body (0 if no Content-Length header) */ diff --git a/test.c b/test.c index 0140a18..c979467 100644 --- a/test.c +++ b/test.c @@ -262,7 +262,6 @@ const struct message requests[] = ,.type= HTTP_REQUEST ,.raw= "POST /post_identity_body_world?q=search#hey HTTP/1.1\r\n" "Accept: */*\r\n" - "Transfer-Encoding: identity\r\n" "Content-Length: 5\r\n" "\r\n" "World" @@ -275,10 +274,9 @@ const struct message requests[] = ,.fragment= "hey" ,.request_path= "/post_identity_body_world" ,.request_url= "/post_identity_body_world?q=search#hey" - ,.num_headers= 3 + ,.num_headers= 2 ,.headers= { { "Accept", "*/*" } - , { "Transfer-Encoding", "identity" } , { "Content-Length", "5" } } ,.body= "World" @@ -1193,6 +1191,61 @@ const struct message requests[] = ,.headers= { { "Host", "example.com" } } ,.body= "" } + +#define POST_MULTI_TE_LAST_CHUNKED 43 +, {.name= "post - multi coding transfer-encoding chunked body" + ,.type= HTTP_REQUEST + ,.raw= "POST / HTTP/1.1\r\n" + "Transfer-Encoding: deflate, chunked\r\n" + "\r\n" + "1e\r\nall your base are belong to us\r\n" + "0\r\n" + "\r\n" + ,.should_keep_alive= TRUE + ,.message_complete_on_eof= FALSE + ,.http_major= 1 + ,.http_minor= 1 + ,.method= HTTP_POST + ,.query_string= "" + ,.fragment= "" + ,.request_path= "/" + ,.request_url= "/" + ,.num_headers= 1 + ,.headers= + { { "Transfer-Encoding" , "deflate, chunked" } + } + ,.body= "all your base are belong to us" + ,.num_chunks_complete= 2 + ,.chunk_lengths= { 0x1e } + } + +#define POST_MULTI_LINE_TE_LAST_CHUNKED 43 +, {.name= "post - multi coding transfer-encoding chunked body" + ,.type= HTTP_REQUEST + ,.raw= "POST / HTTP/1.1\r\n" + "Transfer-Encoding: deflate,\r\n" + " chunked\r\n" + "\r\n" + "1e\r\nall your base are belong to us\r\n" + "0\r\n" + "\r\n" + ,.should_keep_alive= TRUE + ,.message_complete_on_eof= FALSE + ,.http_major= 1 + ,.http_minor= 1 + ,.method= HTTP_POST + ,.query_string= "" + ,.fragment= "" + ,.request_path= "/" + ,.request_url= "/" + ,.num_headers= 1 + ,.headers= + { { "Transfer-Encoding" , "deflate, chunked" } + } + ,.body= "all your base are belong to us" + ,.num_chunks_complete= 2 + ,.chunk_lengths= { 0x1e } + } }; /* * R E S P O N S E S * */ @@ -1970,6 +2023,28 @@ const struct message responses[] = ,.num_chunks_complete= 3 ,.chunk_lengths= { 2, 2 } } +#define HTTP_200_MULTI_TE_NOT_LAST_CHUNKED 28 +, {.name= "HTTP 200 response with `chunked` being *not last* Transfer-Encoding" + ,.type= HTTP_RESPONSE + ,.raw= "HTTP/1.1 200 OK\r\n" + "Transfer-Encoding: chunked, identity\r\n" + "\r\n" + "2\r\n" + "OK\r\n" + "0\r\n" + "\r\n" + ,.should_keep_alive= FALSE + ,.message_complete_on_eof= TRUE + ,.http_major= 1 + ,.http_minor= 1 + ,.status_code= 200 + ,.response_status= "OK" + ,.num_headers= 1 + ,.headers= { { "Transfer-Encoding", "chunked, identity" } + } + ,.body= "2\r\nOK\r\n0\r\n\r\n" + ,.num_chunks_complete= 0 + } }; /* strnlen() is a POSIX.2008 addition. Can't rely on it being available so @@ -3663,7 +3738,7 @@ test_chunked_content_length_error (int req) parsed = http_parser_execute(&parser, &settings_null, buf, strlen(buf)); assert(parsed == strlen(buf)); - buf = "Transfer-Encoding: chunked\r\nContent-Length: 1\r\n\r\n"; + buf = "Transfer-Encoding: anything\r\nContent-Length: 1\r\n\r\n"; size_t buflen = strlen(buf); parsed = http_parser_execute(&parser, &settings_null, buf, buflen); @@ -4332,6 +4407,12 @@ main (void) "fooba", HPE_OK); + // Unknown Transfer-Encoding in request + test_simple("GET / HTTP/1.1\r\n" + "Transfer-Encoding: unknown\r\n" + "\r\n", + HPE_INVALID_TRANSFER_ENCODING); + static const char *all_methods[] = { "DELETE", "GET",