From 92b5cebffa50577bfa9b192926cfd2210f6881c4 Mon Sep 17 00:00:00 2001 From: Andreas Weigel Date: Wed, 15 Feb 2017 12:31:05 +0100 Subject: [PATCH 3/3] fix overflow and refactor websockets decode (Hybi) fix critical heap-based buffer overflow which allowed easy modification of a return address via an overwritten function pointer fix bug causing connections to fail due a "one websocket frame = one ws_read" assumption, which failed with LibVNCServer-0.9.11 refactor websocket Hybi decode to use a simple state machine for decoding of websocket frames --- libvncserver/websockets.c | 609 +++++++++++++++++++++++++++++--------- 1 file changed, 476 insertions(+), 133 deletions(-) diff --git a/libvncserver/websockets.c b/libvncserver/websockets.c index 3c8e99aa..d81b23a8 100644 --- a/libvncserver/websockets.c +++ b/libvncserver/websockets.c @@ -53,6 +53,9 @@ #define B64LEN(__x) (((__x + 2) / 3) * 12 / 3) #define WSHLENMAX 14 /* 2 + sizeof(uint64_t) + sizeof(uint32_t) */ +#define WS_HYBI_MASK_LEN 4 + +#define ARRAYSIZE(a) ((sizeof(a) / sizeof((a[0]))) / (size_t)(!(sizeof(a) % sizeof((a[0]))))) enum { WEBSOCKETS_VERSION_HIXIE, @@ -69,19 +72,19 @@ static int gettid() { typedef int (*wsEncodeFunc)(rfbClientPtr cl, const char *src, int len, char **dst); typedef int (*wsDecodeFunc)(rfbClientPtr cl, char *dst, int len); -typedef struct ws_ctx_s { - char codeBuf[B64LEN(UPDATE_BUF_SIZE) + WSHLENMAX]; /* base64 + maximum frame header length */ - char readbuf[8192]; - int readbufstart; - int readbuflen; - int dblen; - char carryBuf[3]; /* For base64 carry-over */ - int carrylen; - int version; - int base64; - wsEncodeFunc encode; - wsDecodeFunc decode; -} ws_ctx_t; +enum { + /* header not yet received completely */ + WS_HYBI_STATE_HEADER_PENDING, + /* data available */ + WS_HYBI_STATE_DATA_AVAILABLE, + WS_HYBI_STATE_DATA_NEEDED, + /* received a complete frame */ + WS_HYBI_STATE_FRAME_COMPLETE, + /* received part of a 'close' frame */ + WS_HYBI_STATE_CLOSE_REASON_PENDING, + /* */ + WS_HYBI_STATE_ERR +}; typedef union ws_mask_s { char c[4]; @@ -109,6 +112,38 @@ typedef struct __attribute__ ((__packed__)) ws_header_s { } u; } ws_header_t; +typedef struct ws_header_data_s { + ws_header_t *data; + /** bytes read */ + int nRead; + /** mask value */ + ws_mask_t mask; + /** length of frame header including payload len, but without mask */ + int headerLen; + /** length of the payload data */ + int payloadLen; + /** opcode */ + unsigned char opcode; +} ws_header_data_t; + +typedef struct ws_ctx_s { + char codeBufDecode[B64LEN(UPDATE_BUF_SIZE) + WSHLENMAX]; /* base64 + maximum frame header length */ + char codeBufEncode[B64LEN(UPDATE_BUF_SIZE) + WSHLENMAX]; /* base64 + maximum frame header length */ + char *writePos; + unsigned char *readPos; + int readlen; + int hybiDecodeState; + char carryBuf[3]; /* For base64 carry-over */ + int carrylen; + int version; + int base64; + ws_header_data_t header; + int nReadRaw; + int nToRead; + wsEncodeFunc encode; + wsDecodeFunc decode; +} ws_ctx_t; + enum { WS_OPCODE_CONTINUATION = 0x0, @@ -164,6 +199,8 @@ static int webSocketsEncodeHixie(rfbClientPtr cl, const char *src, int len, char static int webSocketsDecodeHybi(rfbClientPtr cl, char *dst, int len); static int webSocketsDecodeHixie(rfbClientPtr cl, char *dst, int len); +static void hybiDecodeCleanup(ws_ctx_t *wsctx); + static int min (int a, int b) { return a < b ? a : b; @@ -421,10 +458,11 @@ webSocketsHandshake(rfbClientPtr cl, char *scheme) wsctx->decode = webSocketsDecodeHixie; } wsctx->base64 = base64; + hybiDecodeCleanup(wsctx); cl->wsctx = (wsCtx *)wsctx; return TRUE; } - + void webSocketsGenMd5(char * target, char *key1, char *key2, char *key3) { @@ -616,146 +654,438 @@ webSocketsDecodeHixie(rfbClientPtr cl, char *dst, int len) } static int -webSocketsDecodeHybi(rfbClientPtr cl, char *dst, int len) +hybiRemaining(ws_ctx_t *wsctx) { - char *buf, *payload; - uint32_t *payload32; - int ret = -1, result = -1; - int total = 0; - ws_mask_t mask; - ws_header_t *header; - int i; - unsigned char opcode; - ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx; - int flength, fhlen; - /* int fin; */ /* not used atm */ - - // rfbLog(" <== %s[%d]: %d cl: %p, wsctx: %p-%p (%d)\n", __func__, gettid(), len, cl, wsctx, (char *)wsctx + sizeof(ws_ctx_t), sizeof(ws_ctx_t)); - - if (wsctx->readbuflen) { - /* simply return what we have */ - if (wsctx->readbuflen > len) { - memcpy(dst, wsctx->readbuf + wsctx->readbufstart, len); - result = len; - wsctx->readbuflen -= len; - wsctx->readbufstart += len; - } else { - memcpy(dst, wsctx->readbuf + wsctx->readbufstart, wsctx->readbuflen); - result = wsctx->readbuflen; - wsctx->readbuflen = 0; - wsctx->readbufstart = 0; - } - goto spor; - } - - buf = wsctx->codeBuf; - header = (ws_header_t *)wsctx->codeBuf; + return wsctx->nToRead - wsctx->nReadRaw; +} - ret = ws_peek(cl, buf, B64LEN(len) + WSHLENMAX); +static void +hybiDecodeCleanup(ws_ctx_t *wsctx) +{ + wsctx->header.payloadLen = 0; + wsctx->header.mask.u = 0; + wsctx->nReadRaw = 0; + wsctx->nToRead= 0; + wsctx->carrylen = 0; + wsctx->readPos = (unsigned char *)wsctx->codeBufDecode; + wsctx->readlen = 0; + wsctx->hybiDecodeState = WS_HYBI_STATE_HEADER_PENDING; + wsctx->writePos = NULL; + rfbLog("cleaned up wsctx\n"); +} - if (ret < 2) { - /* save errno because rfbErr() will tamper it */ - if (-1 == ret) { - int olderrno = errno; - rfbErr("%s: peek; %m\n", __func__); - errno = olderrno; - } else if (0 == ret) { - result = 0; - } else { - errno = EAGAIN; - } - goto spor; +/** + * Return payload data that has been decoded/unmasked from + * a websocket frame. + * + * @param[out] dst destination buffer + * @param[in] len bytes to copy to destination buffer + * @param[in,out] wsctx internal state of decoding procedure + * @param[out] number of bytes actually written to dst buffer + * @return next hybi decoding state + */ +static int +hybiReturnData(char *dst, int len, ws_ctx_t *wsctx, int *nWritten) +{ + int nextState = WS_HYBI_STATE_ERR; + + /* if we have something already decoded copy and return */ + if (wsctx->readlen > 0) { + /* simply return what we have */ + if (wsctx->readlen > len) { + rfbLog("copy to %d bytes to dst buffer; readPos=%p, readLen=%d\n", len, wsctx->readPos, wsctx->readlen); + memcpy(dst, wsctx->readPos, len); + *nWritten = len; + wsctx->readlen -= len; + wsctx->readPos += len; + nextState = WS_HYBI_STATE_DATA_AVAILABLE; + } else { + rfbLog("copy to %d bytes to dst buffer; readPos=%p, readLen=%d\n", wsctx->readlen, wsctx->readPos, wsctx->readlen); + memcpy(dst, wsctx->readPos, wsctx->readlen); + *nWritten = wsctx->readlen; + wsctx->readlen = 0; + wsctx->readPos = NULL; + if (hybiRemaining(wsctx) == 0) { + nextState = WS_HYBI_STATE_FRAME_COMPLETE; + } else { + nextState = WS_HYBI_STATE_DATA_NEEDED; + } } + rfbLog("after copy: readPos=%p, readLen=%d\n", wsctx->readPos, wsctx->readlen); + } else if (wsctx->hybiDecodeState == WS_HYBI_STATE_CLOSE_REASON_PENDING) { + nextState = WS_HYBI_STATE_CLOSE_REASON_PENDING; + } + return nextState; +} - opcode = header->b0 & 0x0f; - /* fin = (header->b0 & 0x80) >> 7; */ /* not used atm */ - flength = header->b1 & 0x7f; - - /* - * 4.3. Client-to-Server Masking - * - * The client MUST mask all frames sent to the server. A server MUST - * close the connection upon receiving a frame with the MASK bit set to 0. - **/ - if (!(header->b1 & 0x80)) { - rfbErr("%s: got frame without mask\n", __func__, ret); - errno = EIO; - goto spor; - } - - if (flength < 126) { - fhlen = 2; - mask = header->m; - } else if (flength == 126 && 4 <= ret) { - flength = WS_NTOH16(header->l16); - fhlen = 4; - mask = header->m16; - } else if (flength == 127 && 10 <= ret) { - flength = WS_NTOH64(header->l64); - fhlen = 10; - mask = header->m64; +/** + * Read an RFC 6455 websocket frame (IETF hybi working group). + * + * Internal state is updated according to bytes received and the + * decoding of header information. + * + * @param[in] cl client ptr with ptr to raw socket and ws_ctx_t ptr + * @param[out] sockRet emulated recv return value + * @return next hybi decoding state; WS_HYBI_STATE_HEADER_PENDING indicates + * that the header was not received completely. + */ +static int +hybiReadHeader(rfbClientPtr cl, int *sockRet) +{ + int ret; + ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx; + char *headerDst = wsctx->codeBufDecode + wsctx->nReadRaw; + int n = WSHLENMAX - wsctx->nReadRaw; + + rfbLog("header_read to %p with len=%d\n", headerDst, n); + ret = ws_read(cl, headerDst, n); + rfbLog("read %d bytes from socket\n", ret); + if (ret <= 0) { + if (-1 == ret) { + /* save errno because rfbErr() will tamper it */ + int olderrno = errno; + rfbErr("%s: peek; %m\n", __func__); + errno = olderrno; + *sockRet = -1; } else { - /* Incomplete frame header */ - rfbErr("%s: incomplete frame header\n", __func__, ret); - errno = EIO; - goto spor; + *sockRet = 0; } + return WS_HYBI_STATE_ERR; + } + + wsctx->nReadRaw += ret; + if (wsctx->nReadRaw < 2) { + /* cannot decode header with less than two bytes */ + errno = EAGAIN; + *sockRet = -1; + return WS_HYBI_STATE_HEADER_PENDING; + } + + /* first two header bytes received; interpret header data and get rest */ + wsctx->header.data = (ws_header_t *)wsctx->codeBufDecode; + + wsctx->header.opcode = wsctx->header.data->b0 & 0x0f; + + /* fin = (header->b0 & 0x80) >> 7; */ /* not used atm */ + wsctx->header.payloadLen = wsctx->header.data->b1 & 0x7f; + rfbLog("first header bytes received; opcode=%d lenbyte=%d\n", wsctx->header.opcode, wsctx->header.payloadLen); + + /* + * 4.3. Client-to-Server Masking + * + * The client MUST mask all frames sent to the server. A server MUST + * close the connection upon receiving a frame with the MASK bit set to 0. + **/ + if (!(wsctx->header.data->b1 & 0x80)) { + rfbErr("%s: got frame without mask ret=%d\n", __func__, ret); + errno = EIO; + *sockRet = -1; + return WS_HYBI_STATE_ERR; + } + + if (wsctx->header.payloadLen < 126 && wsctx->nReadRaw >= 6) { + wsctx->header.headerLen = 2 + WS_HYBI_MASK_LEN; + wsctx->header.mask = wsctx->header.data->u.m; + } else if (wsctx->header.payloadLen == 126 && 8 <= wsctx->nReadRaw) { + wsctx->header.headerLen = 4 + WS_HYBI_MASK_LEN; + wsctx->header.payloadLen = WS_NTOH16(wsctx->header.data->u.s16.l16); + wsctx->header.mask = wsctx->header.data->u.s16.m16; + } else if (wsctx->header.payloadLen == 127 && 14 <= wsctx->nReadRaw) { + wsctx->header.headerLen = 10 + WS_HYBI_MASK_LEN; + wsctx->header.payloadLen = WS_NTOH64(wsctx->header.data->u.s64.l64); + wsctx->header.mask = wsctx->header.data->u.s64.m64; + } else { + /* Incomplete frame header, try again */ + rfbErr("%s: incomplete frame header; ret=%d\n", __func__, ret); + errno = EAGAIN; + *sockRet = -1; + return WS_HYBI_STATE_HEADER_PENDING; + } + + /* absolute length of frame */ + wsctx->nToRead = wsctx->header.headerLen + wsctx->header.payloadLen; + + /* set payload pointer just after header */ + wsctx->writePos = wsctx->codeBufDecode + wsctx->nReadRaw; + + wsctx->readPos = (unsigned char *)(wsctx->codeBufDecode + wsctx->header.headerLen); + + rfbLog("header complete: state=%d flen=%d writeTo=%p\n", wsctx->hybiDecodeState, wsctx->nToRead, wsctx->writePos); + + return WS_HYBI_STATE_DATA_NEEDED; +} + +static int +hybiWsFrameComplete(ws_ctx_t *wsctx) +{ + return wsctx != NULL && hybiRemaining(wsctx) == 0; +} - /* absolute length of frame */ - total = fhlen + flength + 4; - payload = buf + fhlen + 4; /* header length + mask */ +static char * +hybiPayloadStart(ws_ctx_t *wsctx) +{ + return wsctx->codeBufDecode + wsctx->header.headerLen; +} - if (-1 == (ret = ws_read(cl, buf, total))) { +/** + * Read the remaining payload bytes from associated raw socket. + * + * - try to read remaining bytes from socket + * - unmask all multiples of 4 + * - if frame incomplete but some bytes are left, these are copied to + * the carry buffer + * - if opcode is TEXT: Base64-decode all unmasked received bytes + * - set state for reading decoded data + * - reset write position to begin of buffer (+ header) + * --> before we retrieve more data we let the caller clear all bytes + * from the reception buffer + * - execute return data routine + * + * Sets errno corresponding to what it gets from the underlying + * socket or EIO if some internal sanity check fails. + * + * @param[in] cl client ptr with raw socket reference + * @param[out] dst destination buffer + * @param[in] len size of destination buffer + * @param[out] sockRet emulated recv return value + * @return next hybi decode state + */ +static int +hybiReadAndDecode(rfbClientPtr cl, char *dst, int len, int *sockRet) +{ + int n; + int i; + int toReturn; + int toDecode; + int bufsize; + int nextRead; + unsigned char *data; + uint32_t *data32; + ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx; + + /* if data was carried over, copy to start of buffer */ + memcpy(wsctx->writePos, wsctx->carryBuf, wsctx->carrylen); + wsctx->writePos += wsctx->carrylen; + + /* -1 accounts for potential '\0' terminator for base64 decoding */ + bufsize = wsctx->codeBufDecode + ARRAYSIZE(wsctx->codeBufDecode) - wsctx->writePos - 1; + if (hybiRemaining(wsctx) > bufsize) { + nextRead = bufsize; + } else { + nextRead = hybiRemaining(wsctx); + } + + rfbLog("calling read with buf=%p and len=%d (decodebuf=%p headerLen=%d\n)", wsctx->writePos, nextRead, wsctx->codeBufDecode, wsctx->header.headerLen); + + if (wsctx->nReadRaw < wsctx->nToRead) { + /* decode more data */ + if (-1 == (n = ws_read(cl, wsctx->writePos, nextRead))) { int olderrno = errno; rfbErr("%s: read; %m", __func__); errno = olderrno; - return ret; - } else if (ret < total) { - /* GT TODO: hmm? */ - rfbLog("%s: read; got partial data\n", __func__); - } else { - buf[ret] = '\0'; + *sockRet = -1; + return WS_HYBI_STATE_ERR; + } else if (n == 0) { + *sockRet = 0; + return WS_HYBI_STATE_ERR; } - - /* process 1 frame (32 bit op) */ - payload32 = (uint32_t *)payload; - for (i = 0; i < flength / 4; i++) { - payload32[i] ^= mask.u; + wsctx->nReadRaw += n; + rfbLog("read %d bytes from socket; nRead=%d\n", n, wsctx->nReadRaw); + } else { + n = 0; + } + + wsctx->writePos += n; + + if (wsctx->nReadRaw >= wsctx->nToRead) { + if (wsctx->nReadRaw > wsctx->nToRead) { + rfbErr("%s: internal error, read past websocket frame", __func__); + errno=EIO; + *sockRet = -1; + return WS_HYBI_STATE_ERR; } + } + + toDecode = wsctx->writePos - hybiPayloadStart(wsctx); + rfbLog("toDecode=%d from n=%d carrylen=%d headerLen=%d\n", toDecode, n, wsctx->carrylen, wsctx->header.headerLen); + if (toDecode < 0) { + rfbErr("%s: internal error; negative number of bytes to decode: %d", __func__, toDecode); + errno=EIO; + *sockRet = -1; + return WS_HYBI_STATE_ERR; + } + + /* for a possible base64 decoding, we decode multiples of 4 bytes until + * the whole frame is received and carry over any remaining bytes in the carry buf*/ + data = (unsigned char *)hybiPayloadStart(wsctx); + data32= (uint32_t *)data; + + for (i = 0; i < (toDecode >> 2); i++) { + data32[i] ^= wsctx->header.mask.u; + } + rfbLog("mask decoding; i=%d toDecode=%d\n", i, toDecode); + + if (wsctx->hybiDecodeState == WS_HYBI_STATE_FRAME_COMPLETE) { /* process the remaining bytes (if any) */ - for (i*=4; i < flength; i++) { - payload[i] ^= mask.c[i % 4]; - } - - switch (opcode) { - case WS_OPCODE_CLOSE: - rfbLog("got closure, reason %d\n", WS_NTOH16(((uint16_t *)payload)[0])); - errno = ECONNRESET; - break; - case WS_OPCODE_TEXT_FRAME: - if (-1 == (flength = __b64_pton(payload, (unsigned char *)wsctx->codeBuf, sizeof(wsctx->codeBuf)))) { - rfbErr("%s: Base64 decode error; %m\n", __func__); - break; - } - payload = wsctx->codeBuf; - /* fall through */ - case WS_OPCODE_BINARY_FRAME: - if (flength > len) { - memcpy(wsctx->readbuf, payload + len, flength - len); - wsctx->readbufstart = 0; - wsctx->readbuflen = flength - len; - flength = len; - } - memcpy(dst, payload, flength); - result = flength; - break; + for (i*=4; i < toDecode; i++) { + data[i] ^= wsctx->header.mask.c[i % 4]; + } + + /* all data is here, no carrying */ + wsctx->carrylen = 0; + } else { + /* carry over remaining, non-multiple-of-four bytes */ + wsctx->carrylen = toDecode - (i * 4); + if (wsctx->carrylen < 0 || wsctx->carrylen > ARRAYSIZE(wsctx->carryBuf)) { + rfbErr("%s: internal error, invalid carry over size: carrylen=%d, toDecode=%d, i=%d", __func__, wsctx->carrylen, toDecode, i); + *sockRet = -1; + errno = EIO; + return WS_HYBI_STATE_ERR; + } + rfbLog("carrying over %d bytes from %p to %p\n", wsctx->carrylen, wsctx->writePos + (i * 4), wsctx->carryBuf); + memcpy(wsctx->carryBuf, data + (i * 4), wsctx->carrylen); + } + + toReturn = toDecode - wsctx->carrylen; + + switch (wsctx->header.opcode) { + case WS_OPCODE_CLOSE: + + /* this data is not returned as payload data */ + if (hybiWsFrameComplete(wsctx)) { + rfbLog("got closure, reason %d\n", WS_NTOH16(((uint16_t *)data)[0])); + errno = ECONNRESET; + *sockRet = -1; + return WS_HYBI_STATE_FRAME_COMPLETE; + } else { + rfbErr("%s: close reason with long frame not supported", __func__); + errno = EIO; + *sockRet = -1; + return WS_HYBI_STATE_ERR; + } + break; + case WS_OPCODE_TEXT_FRAME: + data[toReturn] = '\0'; + rfbLog("Initiate Base64 decoding in %p with max size %d and '\\0' at %p\n", data, bufsize, data + toReturn); + if (-1 == (wsctx->readlen = b64_pton((char *)data, data, bufsize))) { + rfbErr("Base64 decode error in %s; data=%p bufsize=%d", __func__, data, bufsize); + rfbErr("%s: Base64 decode error; %m\n", __func__); + } + wsctx->writePos = hybiPayloadStart(wsctx); + break; + case WS_OPCODE_BINARY_FRAME: + wsctx->readlen = toReturn; + wsctx->writePos = hybiPayloadStart(wsctx); + break; + default: + rfbErr("%s: unhandled opcode %d, b0: %02x, b1: %02x\n", __func__, (int)wsctx->header.opcode, wsctx->header.data->b0, wsctx->header.data->b1); + } + wsctx->readPos = data; + + return hybiReturnData(dst, len, wsctx, sockRet); +} + +/** + * Read function for websocket-socket emulation. + * + * 0 1 2 3 + * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + * +-+-+-+-+-------+-+-------------+-------------------------------+ + * |F|R|R|R| opcode|M| Payload len | Extended payload length | + * |I|S|S|S| (4) |A| (7) | (16/64) | + * |N|V|V|V| |S| | (if payload len==126/127) | + * | |1|2|3| |K| | | + * +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - + + * | Extended payload length continued, if payload len == 127 | + * + - - - - - - - - - - - - - - - +-------------------------------+ + * | |Masking-key, if MASK set to 1 | + * +-------------------------------+-------------------------------+ + * | Masking-key (continued) | Payload Data | + * +-------------------------------- - - - - - - - - - - - - - - - + + * : Payload Data continued ... : + * + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + + * | Payload Data continued ... | + * +---------------------------------------------------------------+ + * + * Using the decode buffer, this function: + * - reads the complete header from the underlying socket + * - reads any remaining data bytes + * - unmasks the payload data using the provided mask + * - decodes Base64 encoded text data + * - copies len bytes of decoded payload data into dst + * + * Emulates a read call on a socket. + */ +static int +webSocketsDecodeHybi(rfbClientPtr cl, char *dst, int len) +{ + int result = -1; + ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx; + /* int fin; */ /* not used atm */ + + /* rfbLog(" <== %s[%d]: %d cl: %p, wsctx: %p-%p (%d)\n", __func__, gettid(), len, cl, wsctx, (char *)wsctx + sizeof(ws_ctx_t), sizeof(ws_ctx_t)); */ + rfbLog("%s_enter: len=%d; " + "CTX: readlen=%d readPos=%p " + "writeTo=%p " + "state=%d toRead=%d remaining=%d " + " nReadRaw=%d carrylen=%d carryBuf=%p\n", + __func__, len, + wsctx->readlen, wsctx->readPos, + wsctx->writePos, + wsctx->hybiDecodeState, wsctx->nToRead, hybiRemaining(wsctx), + wsctx->nReadRaw, wsctx->carrylen, wsctx->carryBuf); + + switch (wsctx->hybiDecodeState){ + case WS_HYBI_STATE_HEADER_PENDING: + wsctx->hybiDecodeState = hybiReadHeader(cl, &result); + if (wsctx->hybiDecodeState == WS_HYBI_STATE_ERR) { + goto spor; + } + if (wsctx->hybiDecodeState != WS_HYBI_STATE_HEADER_PENDING) { + + /* when header is complete, try to read some more data */ + wsctx->hybiDecodeState = hybiReadAndDecode(cl, dst, len, &result); + } + break; + case WS_HYBI_STATE_DATA_AVAILABLE: + wsctx->hybiDecodeState = hybiReturnData(dst, len, wsctx, &result); + break; + case WS_HYBI_STATE_DATA_NEEDED: + wsctx->hybiDecodeState = hybiReadAndDecode(cl, dst, len, &result); + break; + case WS_HYBI_STATE_CLOSE_REASON_PENDING: + wsctx->hybiDecodeState = hybiReadAndDecode(cl, dst, len, &result); + break; default: - rfbErr("%s: unhandled opcode %d, b0: %02x, b1: %02x\n", __func__, (int)opcode, header->b0, header->b1); + /* invalid state */ + rfbErr("%s: called with invalid state %d\n", wsctx->hybiDecodeState); + result = -1; + errno = EIO; + wsctx->hybiDecodeState = WS_HYBI_STATE_ERR; } /* single point of return, if someone has questions :-) */ spor: /* rfbLog("%s: ret: %d/%d\n", __func__, result, len); */ + if (wsctx->hybiDecodeState == WS_HYBI_STATE_FRAME_COMPLETE) { + rfbLog("frame received successfully, cleaning up: read=%d hlen=%d plen=%d\n", wsctx->header.nRead, wsctx->header.headerLen, wsctx->header.payloadLen); + /* frame finished, cleanup state */ + hybiDecodeCleanup(wsctx); + } else if (wsctx->hybiDecodeState == WS_HYBI_STATE_ERR) { + hybiDecodeCleanup(wsctx); + } + rfbLog("%s_exit: len=%d; " + "CTX: readlen=%d readPos=%p " + "writePos=%p " + "state=%d toRead=%d remaining=%d " + "nRead=%d carrylen=%d carryBuf=%p " + "result=%d\n", + __func__, len, + wsctx->readlen, wsctx->readPos, + wsctx->writePos, + wsctx->hybiDecodeState, wsctx->nToRead, hybiRemaining(wsctx), + wsctx->nReadRaw, wsctx->carrylen, wsctx->carryBuf, + result); return result; } @@ -896,3 +1226,16 @@ webSocketCheckDisconnect(rfbClientPtr cl) return FALSE; } +/* returns TRUE if there is data waiting to be read in our internal buffer + * or if is there any pending data in the buffer of the SSL implementation + */ +rfbBool +webSocketsHasDataInBuffer(rfbClientPtr cl) +{ + ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx; + + if (wsctx && wsctx->readlen) + return TRUE; + + return (cl->sslctx && rfbssl_pending(cl) > 0); +} -- 2.26.2