Initial commit of djbdns-1.05.tar.gz

Source was http://cr.yp.to/djbdns/djbdns-1.05.tar.gz, SHA1 2efdb3a039d0c548f40936aa9cb30829e0ce8c3d

1 files changed, 378 insertions, 0 deletions

diff --git a/axfrdns.c b/axfrdns.c
new file mode 100644
index 0000000..7079850
--- /dev/null
+++ b/axfrdns.c
@@ -0,0 +1,378 @@
+#include <unistd.h>
+#include "droproot.h"
+#include "exit.h"
+#include "env.h"
+#include "uint32.h"
+#include "uint16.h"
+#include "ip4.h"
+#include "tai.h"
+#include "buffer.h"
+#include "timeoutread.h"
+#include "timeoutwrite.h"
+#include "open.h"
+#include "seek.h"
+#include "cdb.h"
+#include "stralloc.h"
+#include "strerr.h"
+#include "str.h"
+#include "byte.h"
+#include "case.h"
+#include "dns.h"
+#include "scan.h"
+#include "qlog.h"
+#include "response.h"
+
+extern int respond(char *,char *,char *);
+
+#define FATAL "axfrdns: fatal: "
+
+void nomem()
+{
+  strerr_die2x(111,FATAL,"out of memory");
+}
+void die_truncated()
+{
+  strerr_die2x(111,FATAL,"truncated request");
+}
+void die_netwrite()
+{
+  strerr_die2sys(111,FATAL,"unable to write to network: ");
+}
+void die_netread()
+{
+  strerr_die2sys(111,FATAL,"unable to read from network: ");
+}
+void die_outside()
+{
+  strerr_die2x(111,FATAL,"unable to locate information in data.cdb");
+}
+void die_cdbread()
+{
+  strerr_die2sys(111,FATAL,"unable to read data.cdb: ");
+}
+void die_cdbformat()
+{
+  strerr_die3x(111,FATAL,"unable to read data.cdb: ","format error");
+}
+
+int safewrite(int fd,char *buf,unsigned int len)
+{
+  int w;
+
+  w = timeoutwrite(60,fd,buf,len);
+  if (w <= 0) die_netwrite();
+  return w;
+}
+
+char netwritespace[1024];
+buffer netwrite = BUFFER_INIT(safewrite,1,netwritespace,sizeof netwritespace);
+
+void print(char *buf,unsigned int len)
+{
+  char tcpheader[2];
+  uint16_pack_big(tcpheader,len);
+  buffer_put(&netwrite,tcpheader,2);
+  buffer_put(&netwrite,buf,len);
+  buffer_flush(&netwrite);
+}
+
+char *axfr;
+static char *axfrok;
+
+void axfrcheck(char *q)
+{
+  int i;
+  int j;
+
+  if (!axfr) return;
+
+  i = j = 0;
+  for (;;) {
+    if (!axfr[i] || (axfr[i] == '/')) {
+      if (i > j) {
+        if (!dns_domain_fromdot(&axfrok,axfr + j,i - j)) nomem();
+        if (dns_domain_equal(q,axfrok)) return;
+      }
+      j = i + 1;
+    }
+    if (!axfr[i]) break;
+    ++i;
+  }
+
+  strerr_die2x(111,FATAL,"disallowed zone transfer request");
+}
+
+static char *zone;
+unsigned int zonelen;
+char typeclass[4];
+
+int fdcdb;
+buffer bcdb;
+char bcdbspace[1024];
+
+void get(char *buf,unsigned int len)
+{
+  int r;
+
+  while (len > 0) {
+    r = buffer_get(&bcdb,buf,len);
+    if (r < 0) die_cdbread();
+    if (!r) die_cdbformat();
+    buf += r;
+    len -= r;
+  }
+}
+
+char ip[4];
+unsigned long port;
+char clientloc[2];
+
+struct tai now;
+char data[32767];
+uint32 dlen;
+uint32 dpos;
+
+void copy(char *buf,unsigned int len)
+{
+  dpos = dns_packet_copy(data,dlen,dpos,buf,len);
+  if (!dpos) die_cdbread();
+}
+
+void doname(stralloc *sa)
+{
+  static char *d;
+  dpos = dns_packet_getname(data,dlen,dpos,&d);
+  if (!dpos) die_cdbread();
+  if (!stralloc_catb(sa,d,dns_domain_length(d))) nomem();
+}
+
+int build(stralloc *sa,char *q,int flagsoa,char id[2])
+{
+  unsigned int rdatapos;
+  char misc[20];
+  char type[2];
+  char recordloc[2];
+  char ttl[4];
+  char ttd[8];
+  struct tai cutoff;
+
+  dpos = 0;
+  copy(type,2);
+  if (flagsoa) if (byte_diff(type,2,DNS_T_SOA)) return 0;
+  if (!flagsoa) if (byte_equal(type,2,DNS_T_SOA)) return 0;
+
+  if (!stralloc_copyb(sa,id,2)) nomem();
+  if (!stralloc_catb(sa,"\204\000\0\0\0\1\0\0\0\0",10)) nomem();
+  copy(misc,1);
+  if ((misc[0] == '=' + 1) || (misc[0] == '*' + 1)) {
+    --misc[0];
+    copy(recordloc,2);
+    if (byte_diff(recordloc,2,clientloc)) return 0;
+  }
+  if (misc[0] == '*') {
+    if (flagsoa) return 0;
+    if (!stralloc_catb(sa,"\1*",2)) nomem();
+  }
+  if (!stralloc_catb(sa,q,dns_domain_length(q))) nomem();
+  if (!stralloc_catb(sa,type,2)) nomem();
+
+  copy(ttl,4);
+  copy(ttd,8);
+  if (byte_diff(ttd,8,"\0\0\0\0\0\0\0\0")) {
+    tai_unpack(ttd,&cutoff);
+    if (byte_equal(ttl,4,"\0\0\0\0")) {
+      if (tai_less(&cutoff,&now)) return 0;
+      uint32_pack_big(ttl,2);
+    }
+    else
+      if (!tai_less(&cutoff,&now)) return 0;
+  }
+
+  if (!stralloc_catb(sa,DNS_C_IN,2)) nomem();
+  if (!stralloc_catb(sa,ttl,4)) nomem();
+  if (!stralloc_catb(sa,"\0\0",2)) nomem();
+  rdatapos = sa->len;
+
+  if (byte_equal(type,2,DNS_T_SOA)) {
+    doname(sa);
+    doname(sa);
+    copy(misc,20);
+    if (!stralloc_catb(sa,misc,20)) nomem();
+  }
+  else if (byte_equal(type,2,DNS_T_NS) || byte_equal(type,2,DNS_T_PTR) || byte_equal(type,2,DNS_T_CNAME)) {
+    doname(sa);
+  }
+  else if (byte_equal(type,2,DNS_T_MX)) {
+    copy(misc,2);
+    if (!stralloc_catb(sa,misc,2)) nomem();
+    doname(sa);
+  }
+  else
+    if (!stralloc_catb(sa,data + dpos,dlen - dpos)) nomem();
+
+  if (sa->len > 65535) die_cdbformat();
+  uint16_pack_big(sa->s + rdatapos - 2,sa->len - rdatapos);
+  return 1;
+}
+
+static struct cdb c;
+static char *q;
+static stralloc soa;
+static stralloc message;
+
+void doaxfr(char id[2])
+{
+  char key[512];
+  uint32 klen;
+  char num[4];
+  uint32 eod;
+  uint32 pos;
+  int r;
+
+  axfrcheck(zone);
+
+  tai_now(&now);
+  cdb_init(&c,fdcdb);
+
+  byte_zero(clientloc,2);
+  key[0] = 0;
+  key[1] = '%';
+  byte_copy(key + 2,4,ip);
+  r = cdb_find(&c,key,6);
+  if (!r) r = cdb_find(&c,key,5);
+  if (!r) r = cdb_find(&c,key,4);
+  if (!r) r = cdb_find(&c,key,3);
+  if (!r) r = cdb_find(&c,key,2);
+  if (r == -1) die_cdbread();
+  if (r && (cdb_datalen(&c) == 2))
+    if (cdb_read(&c,clientloc,2,cdb_datapos(&c)) == -1) die_cdbread();
+
+  cdb_findstart(&c);
+  for (;;) {
+    r = cdb_findnext(&c,zone,zonelen);
+    if (r == -1) die_cdbread();
+    if (!r) die_outside();
+    dlen = cdb_datalen(&c);
+    if (dlen > sizeof data) die_cdbformat();
+    if (cdb_read(&c,data,dlen,cdb_datapos(&c)) == -1) die_cdbformat();
+    if (build(&soa,zone,1,id)) break;
+  }
+
+  cdb_free(&c);
+  print(soa.s,soa.len);
+
+  seek_begin(fdcdb);
+  buffer_init(&bcdb,buffer_unixread,fdcdb,bcdbspace,sizeof bcdbspace);
+
+  pos = 0;
+  get(num,4); pos += 4;
+  uint32_unpack(num,&eod);
+  while (pos < 2048) { get(num,4); pos += 4; }
+
+  while (pos < eod) {
+    if (eod - pos < 8) die_cdbformat();
+    get(num,4); pos += 4;
+    uint32_unpack(num,&klen);
+    get(num,4); pos += 4;
+    uint32_unpack(num,&dlen);
+    if (eod - pos < klen) die_cdbformat();
+    pos += klen;
+    if (eod - pos < dlen) die_cdbformat();
+    pos += dlen;
+
+    if (klen > sizeof key) die_cdbformat();
+    get(key,klen);
+    if (dlen > sizeof data) die_cdbformat();
+    get(data,dlen);
+
+    if ((klen > 1) && (key[0] == 0)) continue; /* location */
+    if (klen < 1) die_cdbformat();
+    if (dns_packet_getname(key,klen,0,&q) != klen) die_cdbformat();
+    if (!dns_domain_suffix(q,zone)) continue;
+    if (!build(&message,q,0,id)) continue;
+    print(message.s,message.len);
+  }
+
+  print(soa.s,soa.len);
+}
+
+void netread(char *buf,unsigned int len)
+{
+  int r;
+
+  while (len > 0) {
+    r = timeoutread(60,0,buf,len);
+    if (r == 0) _exit(0);
+    if (r < 0) die_netread();
+    buf += r; len -= r;
+  }
+}
+
+char tcpheader[2];
+char buf[512];
+uint16 len;
+
+static char seed[128];
+
+int main()
+{
+  unsigned int pos;
+  char header[12];
+  char qtype[2];
+  char qclass[2];
+  const char *x;
+
+  droproot(FATAL);
+  dns_random_init(seed);
+
+  axfr = env_get("AXFR");
+  
+  x = env_get("TCPREMOTEIP");
+  if (x && ip4_scan(x,ip))
+    ;
+  else
+    byte_zero(ip,4);
+
+  x = env_get("TCPREMOTEPORT");
+  if (!x) x = "0";
+  scan_ulong(x,&port);
+
+  for (;;) {
+    netread(tcpheader,2);
+    uint16_unpack_big(tcpheader,&len);
+    if (len > 512) strerr_die2x(111,FATAL,"excessively large request");
+    netread(buf,len);
+
+    pos = dns_packet_copy(buf,len,0,header,12); if (!pos) die_truncated();
+    if (header[2] & 254) strerr_die2x(111,FATAL,"bogus query");
+    if (header[4] || (header[5] != 1)) strerr_die2x(111,FATAL,"bogus query");
+
+    pos = dns_packet_getname(buf,len,pos,&zone); if (!pos) die_truncated();
+    zonelen = dns_domain_length(zone);
+    pos = dns_packet_copy(buf,len,pos,qtype,2); if (!pos) die_truncated();
+    pos = dns_packet_copy(buf,len,pos,qclass,2); if (!pos) die_truncated();
+
+    if (byte_diff(qclass,2,DNS_C_IN) && byte_diff(qclass,2,DNS_C_ANY))
+      strerr_die2x(111,FATAL,"bogus query: bad class");
+
+    qlog(ip,port,header,zone,qtype," ");
+
+    if (byte_equal(qtype,2,DNS_T_AXFR)) {
+      case_lowerb(zone,zonelen);
+      fdcdb = open_read("data.cdb");
+      if (fdcdb == -1) die_cdbread();
+      doaxfr(header);
+      close(fdcdb);
+    }
+    else {
+      if (!response_query(zone,qtype,qclass)) nomem();
+      response[2] |= 4;
+      case_lowerb(zone,zonelen);
+      response_id(header);
+      response[3] &= ~128;
+      if (!(header[2] & 1)) response[2] &= ~1;
+      if (!respond(zone,qtype,ip)) die_outside();
+      print(response,response_len);
+    }
+  }
+}