Fix labels punycode.

src/packet.c

@@ -56,10 +56,11 @@ rdns_make_dns_header (struct rdns_request *req, unsigned int qcount)
 }
 
 static bool
-rdns_maybe_punycode_label (uint8_t *begin, uint8_t **res, uint8_t **dot, unsigned int *label_len)
+rdns_maybe_punycode_label (const uint8_t *begin,
+ uint8_t const **dot, size_t *label_len)
 {
  bool ret = false;
- uint8_t *p = begin;
+ const uint8_t *p = begin;
 
  *dot = NULL;
 
@@ -75,48 +76,96 @@ rdns_maybe_punycode_label (uint8_t *begin, uint8_t **res, uint8_t **dot, unsigne
  }
 
  if (*p) {
- *res = p - 1;
  *label_len = p - begin;
  }
  else {
- *res = p;
  *label_len = p - begin;
  }
 
  return ret;
 }
 
-void
-rdns_format_dns_name (struct rdns_request *req, const char *name, unsigned int namelen)
+bool
+rdns_format_dns_name (struct rdns_resolver *resolver, const char *in,
+ size_t inlen,
+ char **out, size_t *outlen)
 {
- uint8_t *pos = req->packet + req->pos, *dot, *name_pos, *begin;
- unsigned int remain = req->packet_len - req->pos - 5, label_len;
+ const uint8_t *dot;
+ const uint8_t *p = in, *end = in + inlen;
+ char *o;
+ int labels = 0;
+ size_t label_len, olen, remain;
  uint32_t *uclabel;
  size_t punylabel_len, uclabel_len;
- uint8_t tmp_label[DNS_D_MAXLABEL];
- struct rdns_resolver *resolver = req->resolver;
+ char tmp_label[DNS_D_MAXLABEL];
+ bool need_encode = false;
+
+ if (inlen == 0) {
+ inlen = strlen (in);
+ }
+
+ /* Check for non-ascii characters */
+ while (p != end) {
+ if (*p >= 0x80) {
+ need_encode = true;
+ }
+ else if (*p == '.') {
+ labels ++;
+ }
+ p ++;
+ }
+
+ if (!need_encode) {
+ *out = malloc (inlen + 1);
+ if (*out == NULL) {
+ return false;
+ }
+ o = *out;
+ memcpy (o, in, inlen);
+ o[inlen] = '\0';
+ *outlen = inlen;
 
- if (namelen == 0) {
- namelen = strlen (name);
+ return true;
  }
 
- begin = (uint8_t *)name;
- for (;;) {
+ /* We need to encode */
+
+ p = in;
+ olen = inlen + 1 + sizeof ("xn--") * labels;
+ *out = malloc (olen);
+
+ if (*out == NULL) {
+ return false;
+ }
+
+ o = *out;
+ remain = olen;
+
+ while (p != end) {
  /* Check label for unicode characters */
- if (rdns_maybe_punycode_label (begin, &name_pos, &dot, &label_len)) {
+ if (rdns_maybe_punycode_label (p, &dot, &label_len)) {
  /* Convert to ucs4 */
- if (rdns_utf8_to_ucs4 ((char *)begin, label_len, &uclabel, &uclabel_len) == 0) {
+ if (rdns_utf8_to_ucs4 (p, label_len, &uclabel, &uclabel_len) == 0) {
  punylabel_len = DNS_D_MAXLABEL;
 
- rdns_punycode_label_toascii (uclabel, uclabel_len, (char *)tmp_label, &punylabel_len);
- /* Try to compress name */
- *pos++ = (uint8_t)punylabel_len;
- memcpy (pos, tmp_label, punylabel_len);
+ rdns_punycode_label_toascii (uclabel, uclabel_len,
+ tmp_label, &punylabel_len);
+ if (remain >= punylabel_len + 1) {
+ memcpy (o, tmp_label, punylabel_len);
+ o += punylabel_len;
+ *o++ = '.';
+ remain -= punylabel_len + 1;
+ }
+ else {
+ rdns_info ("no buffer remain for punycoding query");
+ free (*out);
+ return false;
+ }
+
  free (uclabel);
- pos += punylabel_len;
+
  if (dot) {
- remain -= label_len + 1;
- begin = dot + 1;
+ p = dot + 1;
  }
  else {
  break;
@@ -133,20 +182,20 @@ rdns_format_dns_name (struct rdns_request *req, const char *name, unsigned int n
  label_len = DNS_D_MAXLABEL;
  }
  if (remain < label_len + 1) {
- label_len = remain - 1;
- rdns_info ("no buffer remain for constructing query, strip to %d", (int)label_len);
+ rdns_info ("no buffer remain for punycoding query");
+ return false;
  }
  if (label_len == 0) {
  /* Two dots in order, skip this */
  rdns_info ("name contains two or more dots in a row, replace it with one dot");
- begin = dot + 1;
+ p = dot + 1;
  continue;
  }
- *pos++ = (uint8_t)label_len;
- memcpy (pos, begin, label_len);
- pos += label_len;
+ memcpy (o, p, label_len);
+ o += label_len;
+ *o++ = '.';
  remain -= label_len + 1;
- begin = dot + 1;
+ p = dot + 1;
  }
  else {
  if (label_len == 0) {
@@ -158,23 +207,27 @@ rdns_format_dns_name (struct rdns_request *req, const char *name, unsigned int n
  label_len = DNS_D_MAXLABEL;
  }
  if (remain < label_len + 1) {
- label_len = remain - 1;
- rdns_info ("no buffer remain for constructing query, strip to %d", (int)label_len);
+ rdns_info ("no buffer remain for punycoding query");
+ return false;
  }
- *pos++ = (uint8_t)label_len;
- memcpy (pos, begin, label_len);
- pos += label_len;
+ memcpy (o, p, label_len);
+ o += label_len;
+ *o++ = '.';
+ remain -= label_len + 1;
+ p = dot + 1;
  break;
  }
  }
  if (remain == 0) {
- rdns_warn ("no buffer space available, aborting");
- break;
+ rdns_info ("no buffer remain for punycoding query");
+ return false;
  }
  }
- /* Termination label */
- *pos = '\0';
- req->pos += pos - (req->packet + req->pos) + 1;
+ *o = '\0';
+
+ *outlen = o - *out;
+
+ return true;
 }
 
 bool

src/packet.h

@@ -49,7 +49,9 @@ void rdns_make_dns_header (struct rdns_request *req, unsigned int qcount);
  * @param name name string
  * @param namelen length of name
  */
-void rdns_format_dns_name (struct rdns_request *req, const char *name, unsigned int namelen);
+bool rdns_format_dns_name (struct rdns_resolver *resolver,
+ const char *name, size_t namelen,
+ char **out, size_t *outlen);
 
 /**
  * Add a resource record to the DNS packet

src/punycode.c

@@ -38,7 +38,8 @@
 static unsigned int
 digit (unsigned n)
 {
- return "abcdefghijklmnopqrstuvwxyz0123456789"[n];
+ static const char ascii[] = "abcdefghijklmnopqrstuvwxyz0123456789";
+ return ascii[n];
 }
 
 static unsigned int

src/resolver.c

@@ -208,7 +208,8 @@ rdns_parse_reply (uint8_t *in, int r, struct rdns_request *req,
  DL_APPEND (rep->entries, elt);
  }
  else {
- rdns_debug ("unknown reply");
+ rdns_debug ("no matching reply for %s",
+ req->requested_names[0].name);
  free (elt);
  }
  }
@@ -425,6 +426,40 @@ rdns_process_retransmit (int fd, void *arg)
  }
 }
 
+static bool
+rdns_maybe_punycode_name (const char *in, size_t inlen,
+ char **out)
+{
+ const char *p = in, *end = in + inlen;
+ bool need_encode = false;
+ uint32_t *ucs_out;
+ size_t out_len;
+
+ while (p != end) {
+ if (*p >= 0x80) {
+ need_encode = true;
+ break;
+ }
+ p ++;
+ }
+
+ if (!need_encode) {
+ *out = malloc (inlen + 1);
+ if (*out == NULL) {
+ return false;
+ }
+ memcpy (*out, in, inlen);
+ (*out)[inlen] = '\0';
+ }
+ else {
+ if (rdns_utf8_to_ucs4 (in, inlen, &ucs_out, &out_len) != 0) {
+ return false;
+ }
+
+ }
+
+}
+
 struct rdns_request*
 rdns_make_request_full (
  struct rdns_resolver *resolver,
@@ -441,6 +476,7 @@ rdns_make_request_full (
  struct rdns_server *serv;
  int r, type;
  unsigned int i, tlen = 0, clen = 0, cur;
+ size_t olen;
  const char *cur_name, *last_name = NULL;
  struct rdns_compression_entry *comp = NULL;
 
@@ -491,16 +527,15 @@ rdns_make_request_full (
  return NULL;
  }
 
- req->requested_names[cur].name = malloc (clen + 1);
- if (req->requested_names[cur].name == NULL) {
+ if (!rdns_format_dns_name (resolver, last_name, clen,
+  &req->requested_names[cur].name, &olen)) {
  rdns_request_free (req);
  return NULL;
  }
- memcpy (req->requested_names[cur].name, last_name, clen);
- req->requested_names[cur].name[clen] = '\0';
+
  type = va_arg (args, int);
  req->requested_names[cur].type = type;
- req->requested_names[cur].len = clen;
+ req->requested_names[cur].len = olen;
  }
  va_end (args);