diff options
Diffstat (limited to 'erts/epmd/src/epmd_srv.c')
| -rw-r--r-- | erts/epmd/src/epmd_srv.c | 212 |
1 files changed, 71 insertions, 141 deletions
diff --git a/erts/epmd/src/epmd_srv.c b/erts/epmd/src/epmd_srv.c index c836bf0bb7..df4d1a5715 100644 --- a/erts/epmd/src/epmd_srv.c +++ b/erts/epmd/src/epmd_srv.c @@ -47,38 +47,6 @@ * | Length | Request | * +--------+---------+ * - * In all but one case there is only one request for each connection made - * to this server so we can safely close the socket after sending the - * reply. The exception is ALIVE_REQ where we keep the connection - * open without sending any data. When we receive a "close" this is - * an indication that the Erlang node was terminated. The termination - * may have been "normal" or caused by a crash. The operating system - * ensure that the connection is closed either way. - * - * Reading is done non-blocking, i.e. we call a "read" only if we are - * told by the "select" function that there are data to read. - * - * Two databases are used: One node database where the registered names - * of the nodes are stored, and one connection database where the state - * of sockets and the data buffers is stored. - * - * Incomplete packets are thrown away after a timout. The Erlang node - * doing the request is responsible for completing in it in a reasonable time. - * - * Note that if the server gets busy it may not have time to - * process all requests for connection. The "accept()" function - * will on most operating systems silently refuse to accept more - * than 5 outstanding requests. It is the client's responsibility - * to retry the request a number of times with random time interval. - * The "-debug" flag will insert a delay so you can test this - * behaviour. - * - * FIXME: In this code we assume that the packets we send on each - * socket is so small that a "write()" never block - * - * FIXME: We never restarts a read or write that was terminated - * by an interrupt. Do we need to? - * */ /* We use separate data structures for node names and connections @@ -98,7 +66,6 @@ static int conn_open(EpmdVars*,int); static int conn_close_fd(EpmdVars*,int); static void node_init(EpmdVars*); -static Node *node_reg(EpmdVars*,char*,int,int); static Node *node_reg2(EpmdVars*,char*, int, int, unsigned char, unsigned char, int, int, int, char*); static int node_unreg(EpmdVars*,char*); static int node_unreg_sock(EpmdVars*,int); @@ -303,11 +270,9 @@ static void do_read(EpmdVars *g,Connection *s) s->fd,val); dbg_print_buf(g,s->buf,val); - /* FIXME: Shouldn't be needed to close down.... */ node_unreg_sock(g,s->fd); epmd_conn_close(g,s); } - /* FIXME: We always close, probably the right thing to do */ return; } @@ -405,6 +370,8 @@ static int do_accept(EpmdVars *g,int listensock) return conn_open(g,msgsock); } +/* buf is actually one byte larger than bsize, + giving place for null termination */ static void do_request(g, fd, s, buf, bsize) EpmdVars *g; int fd; @@ -415,117 +382,23 @@ static void do_request(g, fd, s, buf, bsize) char wbuf[OUTBUF_SIZE]; /* Buffer for writing */ int i; - /* - * Terminate packet as a C string. Needed for requests received from Erlang - * nodes with lower version than R3A. - */ - - buf[bsize] = '\0'; + buf[bsize] = '\0'; /* Needed for strcmp in PORT2 and STOP requests + buf is always large enough */ switch (*buf) { - case EPMD_ALIVE_REQ: - dbg_printf(g,1,"** got ALIVE_REQ"); - - /* The packet has the format "axxyyyyyy" where xx is port, given - in network byte order, and yyyyyy is symname, possibly null - terminated. */ - - if (buf[bsize - 1] == '\000') /* Skip null termination */ - bsize--; - - if (bsize <= 3) - { - dbg_printf(g,0,"packet to small for request ALIVE_REQ (%d)", bsize); - return; - } - - for (i = 3; i < bsize; i++) - if (buf[i] == '\000') - { - dbg_printf(g,0,"node name contains ascii 0 in ALIVE_REQ"); - return; - } - - { - Node *node; - int eport; - char *name = &buf[3]; /* points to node name */ - - eport = get_int16(&buf[1]); - - if ((node = node_reg(g, name, fd, eport)) == NULL) - return; - - wbuf[0] = EPMD_ALIVE_OK_RESP; - put_int16(node->creation, wbuf+1); - - if (g->delay_write) /* Test of busy server */ - sleep(g->delay_write); - - if (reply(g, fd, wbuf, 3) != 3) - { - dbg_tty_printf(g,1,"failed to send ALIVE_OK_RESP for \"%s\"",name); - return; - } - - dbg_tty_printf(g,1,"** sent ALIVE_OK_RESP for \"%s\"",name); - s->keep = EPMD_TRUE; /* Don't close on inactivity */ - } - break; - - case EPMD_PORT_REQ: - dbg_printf(g,1,"** got PORT_REQ"); - - if (buf[bsize - 1] == '\000') /* Skip null termination */ - bsize--; - - if (bsize <= 1) - { - dbg_printf(g,0,"packet to small for request PORT_REQ (%d)", bsize); - return; - } - - for (i = 1; i < bsize; i++) - if (buf[i] == '\000') - { - dbg_printf(g,0,"node name contains ascii 0 in PORT_REQ"); - return; - } - - { - char *name = &buf[1]; /* Points to node name */ - Node *node; - - for (node = g->nodes.reg; node; node = node->next) - { - if (strcmp(node->symname, name) == 0) - { - put_int16(node->port,wbuf); - if (reply(g, fd, wbuf, 2) != 2) - { - dbg_tty_printf(g,1,"failed to send PORT_RESP for %s: %d", - name,node->port); - return; - } - dbg_tty_printf(g,1,"** sent PORT_RESP for %s: %d", - name,node->port); - return; - } - } - dbg_tty_printf(g,1,"Closed on PORT_REQ for %s",name); - } - /* FIXME: How about an answer if no port? Is a close enough? */ - break; - case EPMD_ALIVE2_REQ: dbg_printf(g,1,"** got ALIVE2_REQ"); + if (!s->local_peer) { + dbg_printf(g,0,"ALIVE2_REQ from non local address"); + return; + } /* The packet has the format "axxyyyyyy" where xx is port, given in network byte order, and yyyyyy is symname, possibly null terminated. */ - if (bsize <= 13) + if (bsize <= 13) /* at least one character for the node name */ { dbg_printf(g,0,"packet to small for request ALIVE2_REQ (%d)",bsize); return; @@ -548,7 +421,17 @@ static void do_request(g, fd, s, buf, bsize) highvsn = get_int16(&buf[5]); lowvsn = get_int16(&buf[7]); namelen = get_int16(&buf[9]); + if (namelen + 13 > bsize) { + dbg_printf(g,0,"Node name size error in ALIVE2_REQ"); + return; + } extralen = get_int16(&buf[11+namelen]); + + if (extralen + namelen + 13 > bsize) { + dbg_printf(g,0,"Extra info size error in ALIVE2_REQ"); + return; + } + for (i = 11 ; i < 11 + namelen; i ++) if (buf[i] == '\000') { dbg_printf(g,0,"node name contains ascii 0 in ALIVE2_REQ"); @@ -679,6 +562,10 @@ static void do_request(g, fd, s, buf, bsize) case EPMD_DUMP_REQ: dbg_printf(g,1,"** got DUMP_REQ"); + if (!s->local_peer) { + dbg_printf(g,0,"DUMP_REQ from non local address"); + return; + } { Node *node; @@ -728,7 +615,19 @@ static void do_request(g, fd, s, buf, bsize) break; case EPMD_KILL_REQ: + if (!s->local_peer) { + dbg_printf(g,0,"KILL_REQ from non local address"); + return; + } dbg_printf(g,1,"** got KILL_REQ"); + + if (!g->brutal_kill && (g->nodes.reg != NULL)) { + dbg_printf(g,0,"Disallowed KILL_REQ, live nodes"); + if (reply(g, fd,"NO",2) != 2) + dbg_printf(g,0,"failed to send reply to KILL_REQ"); + return; + } + if (reply(g, fd,"OK",2) != 2) dbg_printf(g,0,"failed to send reply to KILL_REQ"); dbg_tty_printf(g,1,"epmd killed"); @@ -738,6 +637,15 @@ static void do_request(g, fd, s, buf, bsize) case EPMD_STOP_REQ: dbg_printf(g,1,"** got STOP_REQ"); + if (!s->local_peer) { + dbg_printf(g,0,"STOP_REQ from non local address"); + return; + } + if (!g->brutal_kill) { + dbg_printf(g,0,"Disallowed STOP_REQ, no relaxed_command_check"); + return; + } + if (bsize <= 1 ) { dbg_printf(g,0,"packet too small for request STOP_REQ (%d)",bsize); @@ -825,6 +733,14 @@ static int conn_open(EpmdVars *g,int fd) for (i = 0; i < g->max_conn; i++) { if (g->conn[i].open == EPMD_FALSE) { + struct sockaddr_in si; +#ifdef HAVE_SOCKLEN_T + socklen_t st; +#else + int st; +#endif + st = sizeof(si); + g->active_conn++; s = &g->conn[i]; @@ -834,6 +750,20 @@ static int conn_open(EpmdVars *g,int fd) s->fd = fd; s->open = EPMD_TRUE; s->keep = EPMD_FALSE; + + /* Determine if connection is from localhost */ + if (getpeername(s->fd,(struct sockaddr*) &si,&st) || + st < sizeof(si)) { + /* Failure to get peername is regarder as non local host */ + s->local_peer = EPMD_FALSE; + } else { + s->local_peer = + ((((unsigned) ntohl(si.sin_addr.s_addr)) & 0xFF000000U) == + 0x7F000000U); /* Only 127.x.x.x allowed, no false positives */ + } + dbg_tty_printf(g,2,(s->local_peer) ? "Local peer connected" : + "Non-local peer connected"); + s->want = 0; /* Currently unknown */ s->got = 0; s->mod_time = current_time(g); /* Note activity */ @@ -990,11 +920,6 @@ static int node_unreg_sock(EpmdVars *g,int fd) * Perhaps use the oldest or something. */ -static Node *node_reg(EpmdVars *g,char *name,int fd, int port) -{ - return node_reg2(g, name, fd, port, 0, 0, 0, 0, 0, NULL); -} - static Node *node_reg2(EpmdVars *g, char* name, int fd, @@ -1020,6 +945,11 @@ static Node *node_reg2(EpmdVars *g, dbg_printf(g,0,"node name is too long (%d) %s", strlen(name), name); return NULL; } + if (extralen > MAXSYMLEN) + { + dbg_printf(g,0,"extra data is too long (%d) %s", strlen(name), name); + return NULL; + } /* Fail if it is already registered */ |