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Diffstat (limited to 'source/sockspy.c')
| -rw-r--r-- | source/sockspy.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/source/sockspy.c b/source/sockspy.c new file mode 100644 index 00000000000..806b7379157 --- /dev/null +++ b/source/sockspy.c @@ -0,0 +1,302 @@ +/* + USAGE + sockspy desthost destservice + +You install this program in /etc/inetd.conf and /etc/services + +For example I have used these entries: + +/etc/services: +spy 8001/tcp spy port + +/etc/inetd.conf: +spy stream tcp nowait tridge /usr/local/smb/sockspy sockspy fjall netbios-ssn + +This means any connection to port 8001 will be redirected to +netbios-ssn on fjall. By playing with these parameters you can easily +spy on most of the tcp protocols. All packets traversing the link will +be captured. + +NOTE: This program is totally unsupported. I haven't used it for 2 +years, and don't intend to fix the obvious bugs/limitations. I will, +however, accept contributed patches - or even a total rewrite :-) +*/ + +#include <stdio.h> +#include <strings.h> +#include <sys/types.h> +#include <sys/dir.h> +#include <sys/socket.h> +#include <sys/ioctl.h> +#include <netinet/in.h> +#include <netdb.h> + +#include <signal.h> + +#include <errno.h> +#include <sysexits.h> + +int trans_num = 0; + +#ifndef LOGIN +#define LOGIN "/tmp/spy.in" +#endif + +#ifndef LOGOUT +#define LOGOUT "/tmp/spy.out" +#endif + +#ifndef LOGCMD +#define LOGCMD "/tmp/spy.cmd" +#endif + +FILE *cmd = NULL; +FILE *login = NULL; +FILE *logout = NULL; + +#define STREQL(a, b) (strcmp(a, b) == 0) +#define NIL (0) + +char DestHost[256]; /* Remote system to connect to */ +char DestObj[256]; /* Remote object/service to connect to */ + +/* Signal handler for SIGPIPE (write on a disconnected socket) */ +abort() +{ + if (cmd) + { + fprintf(cmd,"writing to disconnected socket!\n"); + fflush(cmd); + } + exit(1); +} + + +main(argc, argv) +int argc; /* # of command line arguments */ +char *argv[]; /* the command line arguments */ +{ + int client, /* Socket connected to client */ + server; /* Socket to use for server */ + + trans_num = 0; +#ifndef NOLOG + login = fopen(LOGIN,"w"); + logout = fopen(LOGOUT,"w"); + cmd = fopen(LOGCMD,"w"); +#endif + + if (cmd) + { + fprintf(cmd,"Started server\n"); + fflush(cmd); + } + + /* Check usage */ + if(argc != 3) + return; + + strcpy(DestHost,argv[1]); + strcpy(DestObj,argv[2]); + + /* Time to attempt the connection */ + server = inet_conn(DestHost, DestObj); + + if( server < 0 ) { + exit(EX_CANTCREAT); + } + + /* Just to make the code more readable */ + client = 0; + + /* We will abort gracefully when the client or remote system + goes away */ + signal(SIGPIPE, abort); + + /* Now just go and move raw data between client and + remote system */ + dowork(client, server); + /* ... NEVER RETURNS ... */ +} + +dowork(client, server) + int client, server; +{ + + /* select(2) masks for client and remote */ + int ClientMask, ServerMask; + + /* Combined ClientMask and ServerMask */ + int ReadMask; + + /* Initialize select(2) masks */ + ClientMask = 1<<client; + ServerMask = 1<<server; + + ReadMask = ClientMask | ServerMask; + + /* Now move raw data for the rest of our life between + client and remote */ + for( ; ; ) { + /* Local Variables */ + int SelectReadMask;/* select(2) mask modifiable by select(2) */ + int nready; /* status return from select(2) */ + + do { + /* Intialize select(2) mask everytime + as select(2) always modifies it */ + SelectReadMask = ReadMask; + + /* Wait for data to be present to be moved */ + errno = 0; + nready = select(32,&SelectReadMask,(int *)0,(int *)0,NIL); + } while( nready < 0 && errno == EINTR ); + + /* select(2) failed, shouldn't happen. Exit abnormally */ + if( nready < 0 ) + exit(EX_SOFTWARE); + + /* Favor the client (for no particular reason) + if s/he is has data */ + if( SelectReadMask & ClientMask ) + { + if (cmd) + fprintf(cmd,"client %d\n",nready); + xfer(client, server,login); + } + + /* Then check on the other guy */ + if( SelectReadMask & ServerMask ) + { + if (cmd) + fprintf(cmd,"server %d\n",nready); + xfer(server, client,logout); + } + } + + /* NEVER REACHED */ +} + +#define BUFSIZE 20000 /* Max bytes to move at a time */ + +xfer(from, to,file) + int from, to; /* Move data from "from" to "to" */ + FILE *file; +{ + static char buf[BUFSIZE]; /* Buffer data to be moved */ + int nready; /* # bytes readable */ + int got; /* # bytes actually being moved */ + int ret; + + /* Query the system how many bytes are ready to be read */ + ioctl(from, FIONREAD, &nready); + + if (cmd) + fprintf(cmd,"nready = %d\n",nready); + + /* Only try to get the smaller of nready and BUFSIZE */ + got = read(from, buf, nready < BUFSIZE ? nready : BUFSIZE); + + /* Zero bytes returned indicates end of stream, exit gracefully */ + if( got == 0 ) + { + if (cmd) + { + fprintf(cmd,"read 0 bytes exiting\n"); + fflush(cmd); + } + if (login) + fclose(login); + if (logout) + fclose(logout); + if (cmd) + fclose(cmd); + exit(EX_OK); + } + + + if (file) + { + fprintf(file,"\nTransaction %d\n",trans_num); + fwrite(buf,got,1,file); + fflush(file); + } + trans_num++; + + /* Now send it accross to the other side */ + ret = write(to, buf, got); + + if (cmd) + { + fprintf(cmd,"wrote %d\n",ret); + if (ret < 0) + fprintf(cmd,"error = %s\n",strerror(errno)); + } +} + +int +inet_conn(host, port) + char *host; + char *port; +{ + /* Local Vars */ + int sock; /* Socket to use for the connection */ + struct hostent *hostent; /* Destination host entry */ + struct servent *servent; /* Destination service entry */ + struct sockaddr_in addr; /* Formated destination for connect */ + + /* Fetch the requested host and service entries */ + hostent = gethostbyname(host); + if (isdigit(*port)) + servent = getservbyport(80, "tcp"); + else + servent = getservbyname(port, "tcp"); + + + if (cmd) + { + fprintf(cmd,"inet_conn %s %s\n",host,port); + + if (servent == NULL) + fprintf(cmd,"servent is NIL\n"); + if (hostent == NULL) + fprintf(cmd,"hostent is NIL\n"); + if (hostent->h_addrtype != AF_INET) + fprintf(cmd,"not inet type\n"); + fflush(cmd); + } + + + /* No host entry, no service entry, or host is not + Internet, error! */ + if( servent == NIL || + hostent == NIL || + hostent->h_addrtype != AF_INET ) + return -1; + + /* Get a socket from the system to use for the connection */ + if( (sock = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) + return -1; + + /* Make sure we start with a clean address structure ... */ + bzero(&addr, sizeof(addr)); + + /* ... then fill in the required fields */ + addr.sin_family = AF_INET; + addr.sin_port = servent->s_port; + bcopy(hostent->h_addr, &addr.sin_addr, hostent->h_length); + + /* Now try to connection to the destination */ + if( connect(sock, &addr, sizeof(addr)) < 0 ) { + /* No go, release the socket, and then return error! */ + close(sock); + return -1; + } + + /* Success. Return the connected socket descriptor */ + if (cmd) + fprintf(cmd,"returning %d\n",sock); + return sock; +} + + |