--- sshd.c.orig Wed May 3 19:21:49 2000 +++ sshd.c Fri May 12 07:11:43 2000 @@ -49,6 +49,13 @@ int deny_severity = LOG_WARNING; #endif /* LIBWRAP */ +#ifdef __FreeBSD__ +#include +#include +#include +#include +#endif /* __FreeBSD__ */ + #ifndef O_NOCTTY #define O_NOCTTY 0 #endif @@ -134,6 +141,32 @@ unsigned char *session_id2 = NULL; int session_id2_len = 0; +/* These are used to implement connections_per_period. */ +struct magic_connection { + struct timeval connections_begin; + unsigned int connections_this_period; +} *magic_connections; +/* Magic number, too! TODO: this doesn't have to be static. */ +const size_t MAGIC_CONNECTIONS_SIZE = 1; + +static __inline int +magic_hash(struct sockaddr_storage *sa) { + + return 0; +} + +static __inline struct timeval +timevaldiff(struct timeval *tv1, struct timeval *tv2) { + struct timeval diff; + int carry; + + carry = tv1->tv_usec > tv2->tv_usec; + diff.tv_sec = tv2->tv_sec - tv1->tv_sec - (carry ? 0 : 1); + diff.tv_usec = tv2->tv_usec - tv1->tv_usec + (carry ? 1000000 : 0); + + return diff; +} + /* Prototypes for various functions defined later in this file. */ void do_ssh1_kex(); void do_ssh2_kex(); @@ -418,6 +451,7 @@ int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, on = 1; pid_t pid; socklen_t fromlen; + int connections_per_period_exceeded = 0; int silent = 0; fd_set *fdset; struct sockaddr_storage from; @@ -763,6 +797,12 @@ fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask); fdset = (fd_set *)xmalloc(fdsetsz); + /* Initialize the magic_connections table. It's magical! */ + magic_connections = calloc(MAGIC_CONNECTIONS_SIZE, + sizeof(struct magic_connection)); + if (magic_connections == NULL) + fatal("calloc: %s", strerror(errno)); + /* * Stay listening for connections until the system crashes or * the daemon is killed with a signal. @@ -794,9 +834,31 @@ error("newsock del O_NONBLOCK: %s", strerror(errno)); continue; } + if (options.connections_per_period != 0) { + struct timeval diff, connections_end; + struct magic_connection *mc; + + (void)gettimeofday(&connections_end, NULL); + mc = &magic_connections[magic_hash(&from)]; + diff = timevaldiff(&mc->connections_begin, &connections_end); + if (diff.tv_sec >= options.connections_period) { + /* + * Slide the window forward only after completely + * leaving it. + */ + mc->connections_begin = connections_end; + mc->connections_this_period = 1; + } else { + if (++mc->connections_this_period > + options.connections_per_period) + connections_per_period_exceeded = 1; + } + } + /* - * Got connection. Fork a child to handle it, unless - * we are in debugging mode. + * Got connection. Fork a child to handle it unless + * we are in debugging mode or the maximum number of + * connections per period has been exceeded. */ if (debug_flag) { /* @@ -810,6 +872,12 @@ sock_out = newsock; pid = getpid(); break; + } else if (connections_per_period_exceeded) { + log("Connection rate limit of %u/%us has been exceeded; " + "dropping connection from %s.", + options.connections_per_period, options.connections_period, + ntop); + connections_per_period_exceeded = 0; } else { /* * Normal production daemon. Fork, and have