/* meta.c -- handle the meta communication Copyright (C) 2000-2017 Guus Sliepen , 2000-2005 Ivo Timmermans 2006 Scott Lamb This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "system.h" #include #include #include "avl_tree.h" #include "connection.h" #include "logger.h" #include "meta.h" #include "net.h" #include "protocol.h" #include "proxy.h" #include "utils.h" #include "xalloc.h" bool send_meta(connection_t *c, const char *buffer, int length) { int outlen; int result; ifdebug(META) logger(LOG_DEBUG, "Sending %d bytes of metadata to %s (%s)", length, c->name, c->hostname); if(!c->outbuflen) { c->last_flushed_time = now; } /* Find room in connection's buffer */ if(length + c->outbuflen > c->outbufsize) { c->outbufsize = length + c->outbuflen; c->outbuf = xrealloc(c->outbuf, c->outbufsize); } if(length + c->outbuflen + c->outbufstart > c->outbufsize) { memmove(c->outbuf, c->outbuf + c->outbufstart, c->outbuflen); c->outbufstart = 0; } /* Add our data to buffer */ if(c->status.encryptout) { /* Check encryption limits */ if((uint64_t)length > c->outbudget) { ifdebug(META) logger(LOG_ERR, "Byte limit exceeded for encryption to %s (%s)", c->name, c->hostname); return false; } else { c->outbudget -= length; } result = EVP_EncryptUpdate(c->outctx, (unsigned char *)c->outbuf + c->outbufstart + c->outbuflen, &outlen, (unsigned char *)buffer, length); if(!result || outlen < length) { logger(LOG_ERR, "Error while encrypting metadata to %s (%s): %s", c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL)); return false; } else if(outlen > length) { logger(LOG_EMERG, "Encrypted data too long! Heap corrupted!"); abort(); } c->outbuflen += outlen; } else { memcpy(c->outbuf + c->outbufstart + c->outbuflen, buffer, length); c->outbuflen += length; } return true; } bool flush_meta(connection_t *c) { int result; ifdebug(META) logger(LOG_DEBUG, "Flushing %d bytes to %s (%s)", c->outbuflen, c->name, c->hostname); while(c->outbuflen) { result = send(c->socket, c->outbuf + c->outbufstart, c->outbuflen, 0); if(result <= 0) { if(!errno || errno == EPIPE) { ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname); } else if(errno == EINTR) { continue; } else if(sockwouldblock(sockerrno)) { ifdebug(META) logger(LOG_DEBUG, "Flushing %d bytes to %s (%s) would block", c->outbuflen, c->name, c->hostname); return true; } else { logger(LOG_ERR, "Flushing meta data to %s (%s) failed: %s", c->name, c->hostname, sockstrerror(sockerrno)); } return false; } c->outbufstart += result; c->outbuflen -= result; } c->outbufstart = 0; /* avoid unnecessary memmoves */ return true; } void broadcast_meta(connection_t *from, const char *buffer, int length) { avl_node_t *node; connection_t *c; for(node = connection_tree->head; node; node = node->next) { c = node->data; if(c != from && c->status.active) { send_meta(c, buffer, length); } } } bool receive_meta(connection_t *c) { int oldlen, i, result; int lenin, lenout, reqlen; bool decrypted = false; char inbuf[MAXBUFSIZE]; /* Strategy: - Read as much as possible from the TCP socket in one go. - Decrypt it. - Check if a full request is in the input buffer. - If yes, process request and remove it from the buffer, then check again. - If not, keep stuff in buffer and exit. */ lenin = recv(c->socket, c->buffer + c->buflen, MAXBUFSIZE - c->buflen, 0); if(lenin <= 0) { if(!lenin || !errno) { ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname); } else if(sockwouldblock(sockerrno)) { return true; } else logger(LOG_ERR, "Metadata socket read error for %s (%s): %s", c->name, c->hostname, sockstrerror(sockerrno)); return false; } oldlen = c->buflen; c->buflen += lenin; while(lenin > 0) { reqlen = 0; /* Is it proxy metadata? */ if(c->allow_request == PROXY) { reqlen = receive_proxy_meta(c); if(reqlen < 0) { return false; } goto consume; } /* Decrypt */ if(c->status.decryptin && !decrypted) { /* Check decryption limits */ if((uint64_t)lenin > c->inbudget) { ifdebug(META) logger(LOG_ERR, "Byte limit exceeded for decryption from %s (%s)", c->name, c->hostname); return false; } else { c->inbudget -= lenin; } result = EVP_DecryptUpdate(c->inctx, (unsigned char *)inbuf, &lenout, (unsigned char *)c->buffer + oldlen, lenin); if(!result || lenout != lenin) { logger(LOG_ERR, "Error while decrypting metadata from %s (%s): %s", c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL)); return false; } memcpy(c->buffer + oldlen, inbuf, lenin); decrypted = true; } /* Are we receiving a TCPpacket? */ if(c->tcplen) { if(c->tcplen <= c->buflen) { if(c->allow_request != ALL) { logger(LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname); return false; } receive_tcppacket(c, c->buffer, c->tcplen); reqlen = c->tcplen; c->tcplen = 0; } } else { /* Otherwise we are waiting for a request */ for(i = oldlen; i < c->buflen; i++) { if(c->buffer[i] == '\n') { c->buffer[i] = '\0'; /* replace end-of-line by end-of-string so we can use sscanf */ c->reqlen = reqlen = i + 1; break; } } if(reqlen && !receive_request(c)) { return false; } } consume: if(reqlen) { c->buflen -= reqlen; lenin -= reqlen - oldlen; memmove(c->buffer, c->buffer + reqlen, c->buflen); oldlen = 0; continue; } else { break; } } if(c->buflen >= MAXBUFSIZE) { logger(LOG_ERR, "Metadata read buffer overflow for %s (%s)", c->name, c->hostname); return false; } return true; }