From 987eae56610dc0d513130d4ae981b7245ebea220 Mon Sep 17 00:00:00 2001 From: Přemysl Janouch Date: Mon, 23 Mar 2015 16:47:21 +0100 Subject: Steady progress Renamed some constants, added basic UTF-8 validation. --- demo-json-rpc-server.c | 167 +++++++++++++++++++++++++++++++++++++------------ 1 file changed, 126 insertions(+), 41 deletions(-) diff --git a/demo-json-rpc-server.c b/demo-json-rpc-server.c index 06f0fc4..806225c 100644 --- a/demo-json-rpc-server.c +++ b/demo-json-rpc-server.c @@ -144,6 +144,61 @@ isspace_ascii (int c) // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +/// Return a pointer to the next UTF-8 character, or NULL on error +static const char * +utf8_next (const char *s, size_t len) +{ + // End of string, we go no further + if (!len) + return NULL; + + // In the middle of a character -> error + const uint8_t *p = (const unsigned char *) s; + if ((*p & 0xC0) == 0x80) + return NULL; + + // Find out how long the sequence is + unsigned mask = 0xC0; + unsigned tail_len = 0; + while ((*p & mask) == mask) + { + // Invalid start of sequence + if (mask == 0xFE) + return NULL; + + mask |= mask >> 1; + tail_len++; + } + + // Check the rest of the sequence + if (tail_len < --len) + return NULL; + + while (tail_len--) + if ((*++p & 0xC0) != 0x80) + return NULL; + + return (const char *) p; +} + +/// Very rough UTF-8 validation, just makes sure codepoints can be iterated +static bool +utf8_validate (const char *s, size_t len) +{ + const char *next; + while (len) + { + if (!(next = utf8_next (s, len))) + return false; + + len -= next - s; + s = next; + } + return true; +} + +// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + static uint8_t g_base64_table[256] = { 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, @@ -1536,23 +1591,22 @@ ws_encode_response_key (const char *key) enum ws_status { - // These names aren't really standard, just somewhat descriptive. - // The RFC isn't really much cleaner about their meaning. + // Named according to the meaning specified in RFC 6455, section 11.2 - WS_STATUS_NORMAL = 1000, - WS_STATUS_GOING_AWAY = 1001, - WS_STATUS_PROTOCOL = 1002, - WS_STATUS_UNACCEPTABLE = 1003, - WS_STATUS_INCONSISTENT = 1007, - WS_STATUS_POLICY = 1008, - WS_STATUS_TOO_BIG = 1009, - WS_STATUS_EXTENSION = 1010, - WS_STATUS_UNEXPECTED = 1011, + WS_STATUS_NORMAL_CLOSURE = 1000, + WS_STATUS_GOING_AWAY = 1001, + WS_STATUS_PROTOCOL_ERROR = 1002, + WS_STATUS_UNSUPPORTED_DATA = 1003, + WS_STATUS_INVALID_PAYLOAD_DATA = 1007, + WS_STATUS_POLICY_VIOLATION = 1008, + WS_STATUS_MESSAGE_TOO_BIG = 1009, + WS_STATUS_MANDATORY_EXTENSION = 1010, + WS_STATUS_INTERNAL_SERVER_ERROR = 1011, // Reserved for internal usage - WS_STATUS_MISSING = 1005, - WS_STATUS_ABNORMAL = 1006, - WS_STATUS_TLS = 1015 + WS_STATUS_NO_STATUS_RECEIVED = 1005, + WS_STATUS_ABNORMAL_CLOSURE = 1006, + WS_STATUS_TLS_HANDSHAKE = 1015 }; // - - Frame parser - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - @@ -1624,7 +1678,7 @@ ws_parser_free (struct ws_parser *self) static void ws_parser_unmask (struct ws_parser *self) { - // Yes, this could be made faster. For example by reading the mask in + // This could be made faster. For example by reading the mask in // native byte ordering and applying it directly here. uint64_t end = self->payload_len & ~(uint64_t) 3; @@ -1747,9 +1801,10 @@ ws_parser_push (struct ws_parser *self, const void *data, size_t len) enum ws_handler_state { - WS_HANDLER_HANDSHAKE, ///< Parsing HTTP + WS_HANDLER_CONNECTING, ///< Parsing HTTP WS_HANDLER_OPEN, ///< Parsing WebSockets frames - WS_HANDLER_CLOSING ///< Closing the connection + WS_HANDLER_CLOSING, ///< Closing the connection + WS_HANDLER_CLOSED ///< Dead }; struct ws_handler @@ -1780,27 +1835,27 @@ struct ws_handler ev_timer ping_timer; ///< Ping timer bool received_pong; ///< Received PONG since the last PING + // TODO: void (*on_handshake) (protocols) that will allow the user + // to choose any sub-protocol, if the client has provided any. + + // TODO: "on_connected" after the handshake has finished? + /// Called upon reception of a single full message bool (*on_message) (void *user_data, enum ws_opcode type, const void *data, size_t len); - // TODO: void (*on_initialized) () that will allow the user to choose - // any sub-protocol, if the client has provided any. - - /// The connection has been closed. - /// @a close_code may, or may not, be one of enum ws_status. - // NOTE: the "close_code" is what we receive from the remote endpoint, - // or one of 1005/1006/1015 - // NOTE: the reason is an empty string if omitted + /// The connection has been closed. @a close_code may, or may not, be one + /// of enum ws_status. The @a reason is never NULL. // TODO; also note that ideally, the handler should (be able to) first // receive a notification about the connection being closed because of // an error (recv()) returns -1, and call on_close() in reaction. + // Actually, calling push() could work pretty fine for this. void (*on_close) (void *user_data, int close_code, const char *reason); /// Write a chunk of data to the stream void (*write_cb) (void *user_data, const void *data, size_t len); - // TODO: close_cb + // TODO: "close_cb"; to be used from a ping timer e.g. void *user_data; ///< User data for callbacks }; @@ -1831,6 +1886,9 @@ ws_handler_fail (struct ws_handler *self, enum ws_status reason) // some flag for the case that we're in the middle of ws_handler_push(), // and/or add a mechanism to stop the caller from polling the socket for // reads). + // TODO: set the state to FAILED (not CLOSED as that means the TCP + // connection is closed) and wait until all is sent? + // TODO: make sure we don't send pings after the close } // TODO: ws_handler_close() that behaves like ws_handler_fail() but doesn't @@ -1842,6 +1900,8 @@ static void ws_handler_send (struct ws_handler *self, enum ws_opcode opcode, const void *data, size_t len) { + // TODO: make sure (just assert?) we're in the OPEN state + struct str header; str_init (&header); str_pack_u8 (&header, 0x80 | (opcode & 0x0F)); @@ -1869,15 +1929,19 @@ ws_handler_on_frame_header (void *user_data, const struct ws_parser *parser) { struct ws_handler *self = user_data; + // Note that we aren't expected to send any close frame before closing the + // connection when the frame is unmasked + if (parser->reserved_1 || parser->reserved_2 || parser->reserved_3 || !parser->is_masked // client -> server payload must be masked || (ws_is_control_frame (parser->opcode) && (!parser->is_fin || parser->payload_len > WS_MAX_CONTROL_PAYLOAD_LEN)) || (!ws_is_control_frame (parser->opcode) && - (self->expecting_continuation && parser->opcode != WS_OPCODE_CONT))) - ws_handler_fail (self, WS_STATUS_PROTOCOL); + (self->expecting_continuation && parser->opcode != WS_OPCODE_CONT)) + || parser->payload_len >= 0x8000000000000000ULL) + ws_handler_fail (self, WS_STATUS_PROTOCOL_ERROR); else if (parser->payload_len > self->max_payload_len) - ws_handler_fail (self, WS_STATUS_TOO_BIG); + ws_handler_fail (self, WS_STATUS_MESSAGE_TOO_BIG); else return true; return false; @@ -1891,6 +1955,9 @@ ws_handler_on_control_frame { case WS_OPCODE_CLOSE: // TODO: confirm the close + // TODO: change the state to CLOSING + // TODO: call "on_close" + // NOTE: the reason is an empty string if omitted break; case WS_OPCODE_PING: ws_handler_send_control (self, WS_OPCODE_PONG, @@ -1901,9 +1968,9 @@ ws_handler_on_control_frame self->received_pong = true; break; default: - // TODO: shouldn't we rather fail on unknown control frames? - // But should we actually return false at any time? Yes? - break; + // Unknown control frame + ws_handler_fail (self, WS_STATUS_PROTOCOL_ERROR); + return false; } return true; } @@ -1918,8 +1985,8 @@ ws_handler_on_frame (void *user_data, const struct ws_parser *parser) // TODO: do this rather in "on_frame_header" if (self->message_data.len + parser->payload_len > self->max_payload_len) { - ws_handler_fail (self, WS_STATUS_TOO_BIG); - return true; + ws_handler_fail (self, WS_STATUS_MESSAGE_TOO_BIG); + return false; } if (!self->expecting_continuation) @@ -1932,6 +1999,13 @@ ws_handler_on_frame (void *user_data, const struct ws_parser *parser) if (!parser->is_fin) return true; + if (self->message_opcode == WS_OPCODE_TEXT + && !utf8_validate (self->parser.input.str, self->parser.input.len)) + { + ws_handler_fail (self, WS_STATUS_INVALID_PAYLOAD_DATA); + return false; + } + bool result = self->on_message (self->user_data, self->message_opcode, self->parser.input.str, self->parser.payload_len); str_reset (&self->message_data); @@ -1976,7 +2050,8 @@ ws_handler_init (struct ws_handler *self) str_init (&self->message_data); self->ping_interval = 60; - // This is still ridiculously high + // This is still ridiculously high. Note that the most significant bit + // must always be zero, i.e. the protocol maximum is 0x7FFF FFFF FFFF FFFF. self->max_payload_len = UINT32_MAX; // Just so we can safely stop it @@ -2124,6 +2199,8 @@ ws_handler_http_response (struct ws_handler *self, const char *status, ...) str_vector_free (&v); } +// TODO: also set the connection to some FAILED state or anything that's neither +// CONNECTING nor OPEN #define FAIL_HANDSHAKE(status, ...) \ BLOCK_START \ ws_handler_http_response (self, (status), __VA_ARGS__); \ @@ -2219,14 +2296,22 @@ ws_handler_finish_handshake (struct ws_handler *self) static bool ws_handler_push (struct ws_handler *self, const void *data, size_t len) { - if (self->state != WS_HANDLER_HANDSHAKE) + if (!len) { - // TODO: handle the case of len == 0: - // OPEN: "on_close" WS_STATUS_ABNORMAL - // CLOSING: just close the connection - return ws_parser_push (&self->parser, data, len); + if (self->state == WS_HANDLER_OPEN) + self->on_close (self->user_data, WS_STATUS_ABNORMAL_CLOSURE, ""); + else + { + // TODO: anything to do besides just closing the connection? + } + + self->state = WS_HANDLER_CLOSED; + return false; } + if (self->state != WS_HANDLER_CONNECTING) + return ws_parser_push (&self->parser, data, len); + // The handshake hasn't been done yet, process HTTP headers static const http_parser_settings http_settings = { @@ -3182,7 +3267,7 @@ client_ws_on_message (void *user_data, if (type != WS_OPCODE_TEXT) { - ws_handler_fail (&self->handler, WS_STATUS_UNACCEPTABLE); + ws_handler_fail (&self->handler, WS_STATUS_UNSUPPORTED_DATA); return false; } -- cgit v1.2.3-70-g09d2