clean up cowbull, some docs

This commit is contained in:
Neale Pickett 2012-01-31 16:45:53 -07:00
parent e98304dbf3
commit f168b002d5
16 changed files with 7234 additions and 33 deletions

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@ -26,6 +26,10 @@ Course questions should be directed to the appropriate instructor:
General questions about Tracer FIRE may be sent to
Neale Pickett <neale@lanl.gov>
Remember: the exercise network should be considered
hostile! Do not bring anything sensitive on your laptop,
and make sure you back everything up.
Looking forward to seeing you in Santa Fe next week,
--

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@ -0,0 +1,19 @@
COWBULL_PKGDIR = $(TARGET)/cowbull
cowbull-install: cowbull-build
mkdir -p $(COWBULL_PKGDIR)
mkdir -p $(COWBULL_PKGDIR)/bin/
$(MAKE) -C packages/cowbull/src install DESTDIR=$(CURDIR)/$(COWBULL_PKGDIR)
$(call COPYTREE, packages/cowbull/service, $(COWBULL_PKGDIR)/service)
cp packages/cowbull/tokens.txt $(COWBULL_PKGDIR)/
cowbull-clean:
rm -rf $(COWBULL_PKGDIR)
$(MAKE) -C packages/cowbull/src clean
cowbull-build:
$(MAKE) -C packages/cowbull/src build
PACKAGES += cowbull

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@ -0,0 +1,4 @@
#! /bin/sh
read IP < ip.txt
ip addr del $IP dev eth0

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@ -0,0 +1 @@
fd84:b410:3441::ec6/64

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@ -0,0 +1,3 @@
#! /bin/sh
exec svlogd -tt $PWD

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@ -0,0 +1,7 @@
#! /bin/sh -e
exec 2>&1
read IP < ip.txt
ip addr add $IP dev eth0 || true
exec setuidgid nobody /opt/cowbull/bin/cowd < /opt/cowbull/tokens.txt

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@ -1 +1,11 @@
DESTDIR ?= /tmp
all: cowd cowcli
cowcli: CC=cc
install: all
cp cowd cowcli $(DESTDIR)/bin/
clean:
rm -f cowd cowcli

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@ -9,10 +9,17 @@
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netdb.h>
#include <fcntl.h>
#define DEBUG
#define NODEBUG
#ifdef DEBUG
# define PORT 4444
#else
# define PORT 44
#endif
int
bind_port(int fd, const struct in6_addr *addr, uint16_t port)
@ -86,7 +93,7 @@ main(int argc, char *argv[])
long answer = 0;
int sock;
int i;
struct in6_addr addr;
struct addrinfo *addr;
uint32_t token = 0;
FILE *in, *out;
@ -94,20 +101,31 @@ main(int argc, char *argv[])
signal(SIGCHLD, sigchld);
if (0 >= inet_pton(AF_INET6, argv[1], &addr)) {
fprintf(stderr, "invalid address: %s\n", argv[1]);
return EX_IOERR;
if (argc < 2) {
fprintf(stderr, "Usage: %s SERVER\n", argv[0]);
return EX_USAGE;
}
{
struct addrinfo hints = { 0 };
hints.ai_family = PF_INET6;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_NUMERICHOST;
if (0 != getaddrinfo(argv[1], "3782", &hints, &addr)) {
perror("Resolving address");
return EX_IOERR;
}
}
/*
* Set up socket
*/
sock = socket(AF_INET6, SOCK_DGRAM, 0);
if (-1 == bind_port(sock, &in6addr_any, 44)) {
if (-1 == bind_port(sock, &in6addr_any, PORT)) {
perror("Binding UDP port 44");
#ifndef DEBUG
return EX_IOERR;
#endif
}
if (argv[2]) {
@ -139,7 +157,7 @@ main(int argc, char *argv[])
}
/* Send the guess */
if (-1 == sendto(sock, &g, sizeof g, 0, &addr, sizeof addr)) {
if (-1 == sendto(sock, &g, sizeof g, 0, addr->ai_addr, addr->ai_addrlen)) {
perror("Sending packet");
return EX_IOERR;
}
@ -156,15 +174,20 @@ main(int argc, char *argv[])
return EX_IOERR;
case 1:
/* It's a score */
printf("%02x\n", buf[0]);
break;
case 4:
/* New game token */
printf("NEW GAME\n");
token = *((uint32_t *) buf);
break;
default:
/* You win: this is your CTF token */
buf[len] = 0;
printf("A WINNER IS YOU: %s\n", buf);
break;
}
}
/* parse result */
/* display result */
}
return 0;

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@ -14,6 +14,8 @@
char tokens[NTOKENS][TOKENLEN];
int ntokens;
char *admonishment = "Try for fewer guesses next time!\n";
struct state {
time_t death;
uint16_t answer;
@ -58,10 +60,14 @@ new_game(int sock, time_t now, struct sockaddr_in6 *from,
for (i = 0; i < 4; i += 1) {
s->answer = (s->answer << 4) | ((random() % 6) + 1);
}
g.token = s->answer;
break;
}
}
printf("=%02x\n", g.token);
if (g.offset < NSTATES) {
sendto(sock, &g, sizeof(g), 0, (struct sockaddr *) from, fromlen);
}
@ -103,7 +109,7 @@ loop(int sock)
}
cur = &states[g.offset];
if ((g.token != cur->answer) || /* Wrong token? */
if ((g.token != cur->answer) || /* Wrong token? */
(cur->death < now) || /* Old game? */
(cur->guesses++ > 100)) { /* Too dumb? */
/*
@ -112,8 +118,8 @@ loop(int sock)
new_game(sock, now, &from, fromlen);
return;
} else {
uint8_t reply;
int i;
uint8_t reply = 0;
int i;
for (i = 0; i < 4; i += 1) {
int s = (g.guess >> (i * 4)) & 0xf;
@ -127,16 +133,22 @@ loop(int sock)
reply += 0x01;
}
}
printf("%02x ? %02x\n", g.guess, reply);
if (reply == 0x40) {
if (cur->guesses > ntokens) {
sendto(sock, tokens[cur->guesses],
strlen(tokens[cur->guesses]), 0,
(struct sockaddr *) &from, fromlen);
char *r;
if (cur->guesses <= ntokens) {
r = tokens[cur->guesses - 1];
} else {
r = admonishment;
}
sendto(sock, r, strlen(r) - 1, 0,
(struct sockaddr *) &from, fromlen);
cur->death = 0;
} else {
sendto(sock, &reply, sizeof reply, 0, (struct sockaddr *) &from,
fromlen);
sendto(sock, &reply, sizeof reply, 0,
(struct sockaddr *) &from, fromlen);
}
}
}
@ -144,7 +156,6 @@ loop(int sock)
int
main(int argc, char *argv[])
{
long answer = 0;
int sock;
int i;
struct in6_addr addr;
@ -180,10 +191,6 @@ main(int argc, char *argv[])
return EX_IOERR;
}
for (i = 0; i < 4; i += 1) {
answer = (answer << 4) | ((random() % 6) + 1);
}
while (1) {
loop(sock);
}

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@ -0,0 +1,10 @@
moo:1000000:xikov-fybir-zurox
moo:9:xukiv-hudyb-fesix
moo:8:xecoh-nyfyh-degix
moo:7:xihap-synik-gesix
moo:6:xegek-rulyz-polux
moo:5:xitiz-fokel-radix
moo:4:xuzif-gakit-fogyx
moo:3:xisav-nodob-besex
moo:2:xumol-peker-pibox
moo:1:xilom-zosyk-cavux

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@ -0,0 +1,91 @@
<!DOCTYPE html>
<html>
<head>
<title>Welcome</title>
<link rel="stylesheet" href="../ctf.css" type="text/css">
</head>
<body>
<h1>Moo.</h1>
<p>
You are trying to guess a 4-nybble sequence. Each nybble will have
either 1 or 2 bits set, and the highest bit will never be set. The
game server will tell you how many nybbles in each guess were correct,
and how many had one correct bit. It does not tell you which
positions.
</p>
<h2>The Cow Client</h2>
<p>
<a href="cowcli">Download the client</a>
</p>
<p>
The client connects to the Cow server running on the IPv6
address provided in argument 1. The client reads a guess
in the form of 4 ASCII numerals, and prints the number of
correct nybbles followed by the number of nybbles with one
correct bit.
</p>
<p>
Here is an example of a session:
</p>
<pre>
1111
12
2222
10
4444
02
4244
12
1244
22
1255
moo:xylep-radar-nanox
</pre>
<p>
You can use a program like <samp>socat</samp> to connect
the client to a logic program you write:
</p>
<pre>
socat EXEC:"./cowcli fd84:b410:3441::ec6" EXEC:./mysolution
</pre>
<p>
This will allow your program to read and write from stdio
of the client program.
</p>
<h2>The Cow Protocol</h2>
<p>
cowd runs on port 3782 on fd84:b410:3441::ec6.
</p>
<p>
The client always sends 6 octets. To request a new session, it sends
all zeroes. Otherwise it sends the 4-octet game identifier provided
by the server, concatenated with a 2-octet guess.
</p>
<p>
The server will respond with a new game identifier (4 octets) to a new
game request or if the game requested is too old. If a guess is
incorrect, the server will respond with either a 1-octet score in
which the high nybble is the number of correct nybbles in the guess,
and the low nybble is the number of nybbles in the guess with one
correct bit. If a guess is correct, the server will respond with a
token of length 5 octets or more.
</p>
<p>
There are multiple tokens, one per number of guesses used, up to
some maximum number of guesses defined per server instance.
</p>
</body>
</html>

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@ -61,11 +61,6 @@ main(int argc, char *argv[])
char needle[400];
my_snprintf(needle, sizeof(needle), "%ld %s", points, answer);
{
FILE *f = fopen("/tmp/form", "w");
fprintf(f, "%s\n%s\n", answer, needle);
fclose(f);
}
if (! fgrepx(needle,
package_path("%s/answers.txt", category))) {

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@ -1 +1 @@
10.0.0.28/24
fd84:b410:3441::b33b/64

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@ -2,7 +2,7 @@
exec 2>&1
read IP < ip.txt
ip addr add $IP label eth0:rlyeh dev eth0
ip addr add $IP label eth0:rlyeh dev eth0 || true
dir=/var/lib/ctf/rlyeh
install -o nobody -d $dir