1 files changed, 497 insertions, 0 deletions

diff --git a/nacl/curvecp/curvecpserver.c b/nacl/curvecp/curvecpserver.c
new file mode 100644
index 00000000..82cc6670
--- /dev/null
+++ b/nacl/curvecp/curvecpserver.c
@@ -0,0 +1,497 @@
+#include <signal.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <poll.h>
+#include "e.h"
+#include "die.h"
+#include "byte.h"
+#include "open.h"
+#include "load.h"
+#include "socket.h"
+#include "uint64_pack.h"
+#include "uint64_unpack.h"
+#include "writeall.h"
+#include "nanoseconds.h"
+#include "safenonce.h"
+#include "nameparse.h"
+#include "hexparse.h"
+#include "portparse.h"
+#include "randommod.h"
+
+#include "randombytes.h"
+#include "crypto_box.h"
+#include "crypto_secretbox.h"
+#if crypto_box_PUBLICKEYBYTES != 32
+error!
+#endif
+#if crypto_box_NONCEBYTES != 24
+error!
+#endif
+#if crypto_box_BOXZEROBYTES != 16
+error!
+#endif
+#if crypto_box_ZEROBYTES != 32
+error!
+#endif
+#if crypto_box_BEFORENMBYTES != 32
+error!
+#endif
+#if crypto_secretbox_KEYBYTES != 32
+error!
+#endif
+#if crypto_secretbox_NONCEBYTES != 24
+error!
+#endif
+#if crypto_secretbox_BOXZEROBYTES != 16
+error!
+#endif
+#if crypto_secretbox_ZEROBYTES != 32
+error!
+#endif
+
+int flagverbose;
+
+#define USAGE "\
+curvecpserver: how to use:\n\
+curvecpserver:   -q (optional): no error messages\n\
+curvecpserver:   -Q (optional): print error messages (default)\n\
+curvecpserver:   -v (optional): print extra information\n\
+curvecpserver:   -c n (optional): allow at most n clients at once (default 100)\n\
+curvecpserver:   sname: server's name\n\
+curvecpserver:   keydir: use this public-key directory\n\
+curvecpserver:   ip: server's IP address\n\
+curvecpserver:   port: server's UDP port\n\
+curvecpserver:   ext: server's extension\n\
+curvecpserver:   prog: run this server\n\
+"
+
+void die_usage(const char *s)
+{
+  if (s) die_4(100,USAGE,"curvecpserver: fatal: ",s,"\n");
+  die_1(100,USAGE);
+}
+
+void die_fatal(const char *trouble,const char *d,const char *fn)
+{
+  if (!flagverbose) die_0(111);
+  if (d) {
+    if (fn) die_9(111,"curvecpserver: fatal: ",trouble," ",d,"/",fn,": ",e_str(errno),"\n");
+    die_7(111,"curvecpserver: fatal: ",trouble," ",d,": ",e_str(errno),"\n");
+  }
+  die_5(111,"curvecpserver: fatal: ",trouble,": ",e_str(errno),"\n");
+}
+
+int ipparse(unsigned char *y,const char *x)
+{
+  long long j;
+  long long k;
+  long long d;
+
+  for (k = 0;k < 4;++k) y[k] = 0;
+  for (k = 0;k < 4;++k) {
+    d = 0;
+    for (j = 0;j < 3 && x[j] >= '0' && x[j] <= '9';++j) d = d * 10 + (x[j] - '0');
+    if (j == 0) return 0;
+    x += j;
+    if (k >= 0 && k < 4) y[k] = d;
+    if (k < 3) {
+      if (*x != '.') return 0;
+      ++x;
+    }
+  }
+  if (*x) return 0;
+  return 1;
+}
+
+int maxparse(long long *y,const char *x)
+{
+  long long d;
+  long long j;
+
+  d = 0;
+  for (j = 0;j < 9 && x[j] >= '0' && x[j] <= '9';++j) d = d * 10 + (x[j] - '0');
+  if (x[j]) return 0;
+  if (d < 1) return 0;
+  if (d > 65535) return 0;
+  *y = d;
+  return 1;
+}
+
+/* cookies: */
+long long nextminute;
+unsigned char minutekey[32];
+unsigned char lastminutekey[32];
+
+/* routing to the server: */
+unsigned char serverip[4];
+unsigned char serverport[2];
+unsigned char serverextension[16];
+int udpfd = -1;
+
+/* server security: */
+char *keydir = 0;
+unsigned char servername[256];
+unsigned char serverlongtermsk[32];
+unsigned char servershorttermpk[32];
+unsigned char servershorttermsk[32];
+
+/* routing to the client: */
+unsigned char clientextension[16];
+
+/* client security: */
+unsigned char clientlongtermpk[32];
+unsigned char clientshorttermpk[32];
+
+/* shared secrets: */
+unsigned char clientshortserverlong[32];
+unsigned char clientshortservershort[32];
+unsigned char clientlongserverlong[32];
+
+unsigned char allzero[128] = {0};
+
+unsigned char nonce[24];
+unsigned char text[2048];
+
+unsigned char packetip[4];
+unsigned char packetport[2];
+unsigned char packet[4096];
+crypto_uint64 packetnonce;
+
+#define MESSAGELEN 1104
+
+struct activeclient {
+  unsigned char clientshorttermpk[32];
+  unsigned char clientshortservershort[32];
+  crypto_uint64 receivednonce;
+  crypto_uint64 sentnonce;
+  long long messagelen;
+  pid_t child;
+  int tochild;
+  int fromchild;
+  unsigned char clientextension[16];
+  unsigned char clientip[4];
+  unsigned char clientport[2];
+  unsigned char message[MESSAGELEN];
+} ;
+
+const char *strmaxactiveclients = "100";
+long long maxactiveclients = 0;
+long long numactiveclients = 0;
+struct activeclient *activeclients = 0;
+struct pollfd *p;
+
+int fdwd = -1;
+
+int pi0[2];
+int pi1[2];
+
+unsigned char childbuf[4096];
+long long childbuflen = 0;
+unsigned char childmessage[2048];
+long long childmessagelen = 0;
+
+int main(int argc,char **argv)
+{
+  long long r;
+  long long i;
+  long long k;
+
+  signal(SIGPIPE,SIG_IGN);
+  signal(SIGCHLD,SIG_IGN);
+
+  if (!argv[0]) die_usage(0);
+  for (;;) {
+    char *x;
+    if (!argv[1]) break;
+    if (argv[1][0] != '-') break;
+    x = *++argv;
+    if (x[0] == '-' && x[1] == 0) break;
+    if (x[0] == '-' && x[1] == '-' && x[2] == 0) break;
+    while (*++x) {
+      if (*x == 'q') { flagverbose = 0; continue; }
+      if (*x == 'Q') { flagverbose = 1; continue; }
+      if (*x == 'v') { if (flagverbose == 2) flagverbose = 3; else flagverbose = 2; continue; }
+      if (*x == 'c') {
+        if (x[1]) { strmaxactiveclients = x + 1; break; }
+        if (argv[1]) { strmaxactiveclients = *++argv; break; }
+      }
+      die_usage(0);
+    }
+  }
+  if (!maxparse(&maxactiveclients,strmaxactiveclients)) die_usage("concurrency must be between 1 and 65535");
+  if (!nameparse(servername,*++argv)) die_usage("sname must be at most 255 bytes, at most 63 bytes between dots");
+  keydir = *++argv; if (!keydir) die_usage("missing keydir");
+  if (!ipparse(serverip,*++argv)) die_usage("ip must be an IPv4 address");
+  if (!portparse(serverport,*++argv)) die_usage("port must be an integer between 0 and 65535");
+  if (!hexparse(serverextension,16,*++argv)) die_usage("ext must be exactly 32 hex characters");
+  if (!*++argv) die_usage("missing prog");
+
+  for (;;) {
+    r = open_read("/dev/null");
+    if (r == -1) die_fatal("unable to open /dev/null",0,0);
+    if (r > 9) { close(r); break; }
+  }
+
+  activeclients = malloc(maxactiveclients * sizeof(struct activeclient));
+  if (!activeclients) die_fatal("unable to create activeclients array",0,0);
+  randombytes((void *) activeclients,maxactiveclients * sizeof(struct activeclient));
+  for (i = 0;i < maxactiveclients;++i) {
+    activeclients[i].child = -1;
+    activeclients[i].tochild = -1;
+    activeclients[i].fromchild = -1;
+    activeclients[i].receivednonce = 0;
+    activeclients[i].sentnonce = randommod(281474976710656LL);
+  }
+  
+  p = malloc((1 + maxactiveclients) * sizeof(struct pollfd));
+  if (!p) die_fatal("unable to create poll array",0,0);
+
+  fdwd = open_cwd();
+  if (fdwd == -1) die_fatal("unable to open current directory",0,0);
+
+  if (chdir(keydir) == -1) die_fatal("unable to chdir to",keydir,0);
+  if (load(".expertsonly/secretkey",serverlongtermsk,sizeof serverlongtermsk) == -1) die_fatal("unable to read secret key from",keydir,0);
+
+  udpfd = socket_udp();
+  if (udpfd == -1) die_fatal("unable to create socket",0,0);
+  if (socket_bind(udpfd,serverip,serverport) == -1) die_fatal("unable to bind socket",0,0);
+
+  randombytes(minutekey,sizeof minutekey);
+  randombytes(lastminutekey,sizeof lastminutekey);
+  nextminute = nanoseconds() + 60000000000ULL;
+
+  for (;;) {
+    long long timeout = nextminute - nanoseconds();
+    if (timeout <= 0) {
+      timeout = 60000000000ULL;
+      byte_copy(lastminutekey,sizeof lastminutekey,minutekey);
+      randombytes(minutekey,sizeof minutekey);
+      nextminute = nanoseconds() + timeout;
+      randombytes(packet,sizeof packet);
+      randombytes(packetip,sizeof packetip);
+      randombytes(packetport,sizeof packetport);
+      randombytes(clientshorttermpk,sizeof clientshorttermpk);
+      randombytes(clientshortserverlong,sizeof clientshortserverlong);
+      randombytes(nonce,sizeof nonce);
+      randombytes(text,sizeof text);
+      randombytes(childbuf,sizeof childbuf);
+      randombytes(childmessage,sizeof childmessage);
+      randombytes(servershorttermpk,sizeof servershorttermpk);
+      randombytes(servershorttermsk,sizeof servershorttermsk);
+    }
+
+    for (i = 0;i < numactiveclients;++i) {
+      p[i].fd = activeclients[i].fromchild;
+      p[i].events = POLLIN;
+    }
+    p[numactiveclients].fd = udpfd;
+    p[numactiveclients].events = POLLIN;
+    if (poll(p,1 + numactiveclients,timeout / 1000000 + 1) < 0) continue;
+
+    do { /* try receiving a packet: */
+      if (!p[numactiveclients].revents) break;
+      r = socket_recv(udpfd,packet,sizeof packet,packetip,packetport);
+      if (r < 80) break;
+      if (r > 1184) break;
+      if (r & 15) break;
+      if (!(byte_isequal(packet,7,"QvnQ5Xl") & byte_isequal(packet + 8,16,serverextension))) break;
+      byte_copy(clientextension,16,packet + 24);
+      if (packet[7] == 'H') { /* Hello packet: */
+        if (r != 224) break;
+        byte_copy(clientshorttermpk,32,packet + 40);
+        crypto_box_beforenm(clientshortserverlong,clientshorttermpk,serverlongtermsk);
+        byte_copy(nonce,16,"CurveCP-client-H");
+        byte_copy(nonce + 16,8,packet + 136);
+        byte_zero(text,16);
+        byte_copy(text + 16,80,packet + 144);
+        if (crypto_box_open_afternm(text,text,96,nonce,clientshortserverlong)) break;
+
+        /* send Cookie packet: */
+
+        crypto_box_keypair(servershorttermpk,servershorttermsk);
+        byte_zero(text + 64,32);
+        byte_copy(text + 96,32,clientshorttermpk);
+        byte_copy(text + 128,32,servershorttermsk);
+        byte_copy(nonce,8,"minute-k");
+        if (safenonce(nonce + 8,1) == -1) die_fatal("nonce-generation disaster",0,0);
+        crypto_secretbox(text + 64,text + 64,96,nonce,minutekey);
+        byte_copy(text + 64,16,nonce + 8);
+
+        byte_zero(text,32);
+        byte_copy(text + 32,32,servershorttermpk);
+        byte_copy(nonce,8,"CurveCPK"); /* reusing the other 16 bytes */
+        crypto_box_afternm(text,text,160,nonce,clientshortserverlong);
+
+        byte_copy(packet,8,"RL3aNMXK");
+        byte_copy(packet + 8,16,clientextension);
+        byte_copy(packet + 24,16,serverextension);
+        byte_copy(packet + 40,16,nonce + 8);
+        byte_copy(packet + 56,144,text + 16);
+
+        socket_send(udpfd,packet,200,packetip,packetport);
+      }
+      if (packet[7] == 'I') { /* Initiate packet: */
+        if (r < 560) break;
+        for (i = 0;i < numactiveclients;++i) /* XXX use better data structure */
+          if (byte_isequal(activeclients[i].clientshorttermpk,32,packet + 40))
+            break;
+        if (i < numactiveclients) {
+          packetnonce = uint64_unpack(packet + 168);
+          if (packetnonce <= activeclients[i].receivednonce) break;
+          byte_copy(nonce,16,"CurveCP-client-I");
+          byte_copy(nonce + 16,8,packet + 168);
+          byte_zero(text,16);
+          byte_copy(text + 16,r - 176,packet + 176);
+          if (crypto_box_open_afternm(text,text,r - 160,nonce,activeclients[i].clientshortservershort)) break;
+
+          /* XXX: update clientip, clientextension; but not if client has spoken recently */
+          activeclients[i].receivednonce = packetnonce;
+          text[383] = (r - 544) >> 4;
+          if (writeall(activeclients[i].tochild,text + 383,r - 543) == -1)
+            ; /* child is gone; will see eof later */
+          break;
+        }
+        if (i == maxactiveclients) break;
+
+        byte_copy(nonce,8,"minute-k");
+        byte_copy(nonce + 8,16,packet + 72);
+        byte_zero(text,16);
+        byte_copy(text + 16,80,packet + 88);
+        if (crypto_secretbox_open(text,text,96,nonce,minutekey)) {
+          byte_zero(text,16);
+          byte_copy(text + 16,80,packet + 88);
+          if (crypto_secretbox_open(text,text,96,nonce,lastminutekey)) break;
+        }
+        if (!byte_isequal(packet + 40,32,text + 32)) break;
+        byte_copy(servershorttermsk,32,text + 64);
+        byte_copy(clientshorttermpk,32,packet + 40);
+        crypto_box_beforenm(clientshortservershort,clientshorttermpk,servershorttermsk);
+
+        byte_copy(nonce,16,"CurveCP-client-I");
+        byte_copy(nonce + 16,8,packet + 168);
+        byte_zero(text,16);
+        byte_copy(text + 16,r - 176,packet + 176);
+        if (crypto_box_open_afternm(text,text,r - 160,nonce,clientshortservershort)) break;
+
+        if (!byte_isequal(text + 128,256,servername)) break;
+
+        /* XXX skip if client authentication is not desired: */
+        byte_copy(clientlongtermpk,32,text + 32);
+        /* XXX impose policy limitations on clients: known, maxconn */
+        /* XXX for known clients, retrieve shared secret from cache: */
+        crypto_box_beforenm(clientlongserverlong,clientlongtermpk,serverlongtermsk);
+        byte_copy(nonce,8,"CurveCPV");
+        byte_copy(nonce + 8,16,text + 64);
+        byte_zero(text + 64,16);
+        if (crypto_box_open_afternm(text + 64,text + 64,64,nonce,clientlongserverlong)) break;
+        if (!byte_isequal(text + 96,32,clientshorttermpk)) break;
+
+        if (open_pipe(pi0) == -1) break; /* XXX: error message */
+        if (open_pipe(pi1) == -1) { close(pi0[0]); close(pi0[1]); break; } /* XXX: error message */
+
+        activeclients[i].child = fork();
+        if (activeclients[i].child == -1) {
+          close(pi0[0]); close(pi0[1]);
+          close(pi1[0]); close(pi1[1]);
+          break; /* XXX: error message */
+        }
+        if (activeclients[i].child == 0) {
+          if (fchdir(fdwd) == -1) die_fatal("unable to chdir to original directory",0,0);
+          close(8);
+          if (dup(pi0[0]) != 8) die_fatal("unable to dup",0,0);
+          close(9);
+          if (dup(pi1[1]) != 9) die_fatal("unable to dup",0,0);
+          /* XXX: set up environment variables */
+          signal(SIGPIPE,SIG_DFL);
+          signal(SIGCHLD,SIG_DFL);
+          execvp(*argv,argv);
+          die_fatal("unable to run",*argv,0);
+        }
+
+        activeclients[i].tochild = pi0[1]; close(pi0[0]);
+        activeclients[i].fromchild = pi1[0]; close(pi1[1]);
+        activeclients[i].messagelen = 0;
+        byte_copy(activeclients[i].clientshorttermpk,32,clientshorttermpk);
+        byte_copy(activeclients[i].clientshortservershort,32,clientshortservershort);
+        activeclients[i].receivednonce = uint64_unpack(packet + 168);
+        byte_copy(activeclients[i].clientextension,16,clientextension);
+        byte_copy(activeclients[i].clientip,4,packetip);
+        byte_copy(activeclients[i].clientport,2,packetport);
+        ++numactiveclients;
+
+        text[383] = (r - 544) >> 4;
+        if (writeall(activeclients[i].tochild,text + 383,r - 543) == -1)
+          ; /* child is gone; will see eof later */
+      }
+      if (packet[7] == 'M') { /* Message packet: */
+        if (r < 112) break;
+        for (i = 0;i < numactiveclients;++i) /* XXX use better data structure */
+          if (byte_isequal(activeclients[i].clientshorttermpk,32,packet + 40))
+            break;
+        if (i < numactiveclients) {
+          packetnonce = uint64_unpack(packet + 72);
+          if (packetnonce <= activeclients[i].receivednonce) break;
+          byte_copy(nonce,16,"CurveCP-client-M");
+          byte_copy(nonce + 16,8,packet + 72);
+          byte_zero(text,16);
+          byte_copy(text + 16,r - 80,packet + 80);
+          if (crypto_box_open_afternm(text,text,r - 64,nonce,activeclients[i].clientshortservershort)) break;
+
+          /* XXX: update clientip, clientextension */
+          activeclients[i].receivednonce = packetnonce;
+          text[31] = (r - 96) >> 4;
+          if (writeall(activeclients[i].tochild,text + 31,r - 95) == -1)
+            ; /* child is gone; will see eof later */
+          break;
+        }
+      }
+    } while (0);
+
+    for (i = numactiveclients - 1;i >= 0;--i) {
+      do {
+        if (!p[i].revents) break;
+        r = read(activeclients[i].fromchild,childbuf,sizeof childbuf);
+        if (r == -1) if (errno == EINTR || errno == EWOULDBLOCK || errno == EAGAIN) break;
+        if (r <= 0) goto endconnection;
+        childbuflen = r;
+        for (k = 0;k < childbuflen;++k) {
+          r = activeclients[i].messagelen;
+          if (r < 0) goto endconnection;
+          if (r >= MESSAGELEN) goto endconnection;
+          activeclients[i].message[r] = childbuf[k];
+          if (r == 0) if (childbuf[k] & 128) goto endconnection;
+          activeclients[i].messagelen = r + 1;
+          if (r == 16 * (unsigned long long) activeclients[i].message[0]) {
+            if (r < 16) goto endconnection;
+            if (r > 1088) goto endconnection;
+            byte_copy(nonce,16,"CurveCP-server-M");
+            uint64_pack(nonce + 16,++activeclients[i].sentnonce);
+            byte_zero(text,32);
+            byte_copy(text + 32,r,activeclients[i].message + 1);
+            crypto_box_afternm(text,text,r + 32,nonce,activeclients[i].clientshortservershort);
+            byte_copy(packet,8,"RL3aNMXM");
+            byte_copy(packet + 8,16,clientextension);
+            byte_copy(packet + 24,16,serverextension);
+            byte_copy(packet + 40,8,nonce + 16);
+            byte_copy(packet + 48,r + 16,text + 16);
+            socket_send(udpfd,packet,r + 64,activeclients[i].clientip,activeclients[i].clientport);
+            activeclients[i].messagelen = 0;
+          }
+        }
+        break;
+
+        endconnection:
+
+        /* XXX: cache cookie if it's recent */
+        close(activeclients[i].fromchild); activeclients[i].fromchild = -1;
+        close(activeclients[i].tochild); activeclients[i].tochild = -1;
+        --numactiveclients;
+        activeclients[i] = activeclients[numactiveclients];
+        randombytes((void *) &activeclients[numactiveclients],sizeof(struct activeclient));
+      } while (0);
+    }
+  }
+}