[PATCH 3/4] getaddrinfo: rewrite inet servname resolution

[Pavel Simerda <psimerda at redhat dot com>]

Move servname resolution into a separate function, clean it up
and make it behave correctly and consistently. Check upper bound
of numeric port input.

Resolves:

https://sourceware.org/bugzilla/show_bug.cgi?id=14990
https://sourceware.org/bugzilla/show_bug.cgi?id=16208

	* sysdeps/posix/getaddrinfo.c (struct gaih_service): Remove definition.
	(struct gaih_typeproto): Remove dummy item.
	(getportbyname): Add function definition.
	(gaih_inet_serv): Remove function definition.
	(free_service_list): Add function definition.
	(get_service_list): Add function definition.
	(gaih_inet): Rename to getaddrinfo_inet().
	(getaddrinfo_inet): Remove old servname resolution code.
	(getaddrinfo_inet): Use get_service_list() instead.
	(getaddrinfo_inet): Ensure free_service_list() is called on error.
	(getaddrinfo): Remove old servname resolution code.
	(getaddrinfo): Call getaddrinfo_inet().

diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c
index 1300238..94b21e9 100644
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -71,12 +71,6 @@ extern int __idna_to_unicode_lzlz (const char *input, char **output,
 # include <libidn/idna.h>
 #endif
 
-struct gaih_service
-  {
-    const char *name;
-    int num;
-  };
-
 struct gaih_servtuple
   {
     struct gaih_servtuple *next;
@@ -103,7 +97,6 @@ struct gaih_typeproto
 
 static const struct gaih_typeproto gaih_inet_typeproto[] =
 {
-  { 0, 0, 0, false, "" },
   { SOCK_STREAM, IPPROTO_TCP, 0, true, "tcp" },
   { SOCK_DGRAM, IPPROTO_UDP, 0, true, "udp" },
 #if defined SOCK_DCCP && defined IPPROTO_DCCP
@@ -132,10 +125,8 @@ static const struct addrinfo default_hints =
     .ai_next = NULL
   };
 
-
 static int
-gaih_inet_serv (const char *servicename, const struct gaih_typeproto *tp,
-		const struct addrinfo *req, struct gaih_servtuple *st)
+getportbyname (const char *servname, const char *proto)
 {
   struct servent *s;
   size_t tmpbuflen = 1024;
@@ -147,7 +138,7 @@ gaih_inet_serv (const char *servicename, const struct gaih_typeproto *tp,
     {
       tmpbuf = __alloca (tmpbuflen);
 
-      r = __getservbyname_r (servicename, tp->name, &ts, tmpbuf, tmpbuflen,
+      r = __getservbyname_r (servname, proto, &ts, tmpbuf, tmpbuflen,
 			     &s);
       if (r != 0 || s == NULL)
 	{
@@ -159,12 +150,109 @@ gaih_inet_serv (const char *servicename, const struct gaih_typeproto *tp,
     }
   while (r);
 
-  st->next = NULL;
-  st->socktype = tp->socktype;
-  st->protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
-		  ? req->ai_protocol : tp->protocol);
-  st->port = s->s_port;
+  return s->s_port;
+}
+
+static void
+free_service_list (struct gaih_servtuple *st)
+{
+  while (st)
+    {
+      struct gaih_servtuple *tmp = st;
+      st = st->next;
+      free (tmp);
+    }
+}
+
+static int
+get_service_list (const char *servname, int socktype, int protocol, int flags, struct gaih_servtuple **servtuple)
+{
+  if (!servname)
+    {
+      /* POSIX1-2008: If servname is null, the call shall return network-level
+       * addresses for the specified nodename.
+       *
+       * Example:
+       *
+       * getaddrinfo ("localhost", NULL, ...) ->
+       *   family=AF_INET6 socktype=0 protocol=0 address=::1 port=0
+       *   family=AF_INET socktype=0 protocol=0 address=127.0.0.1 port=0
+       */
+      struct gaih_servtuple *st = malloc (sizeof (struct gaih_servtuple));
+      if (!st)
+        return EAI_MEMORY;
+      st->next = NULL;
+      st->socktype = 0;
+      st->protocol = 0;
+      st->port = 0;
+
+      *servtuple = st;
+      return 0;
+    }
+
+  int port;
+  char *ptr;
+  /* POSIX1-2008: If the specified address family is AF_INET, AF_INET6,
+   * AF_UNSPEC, the service can be specified as a string specifying a
+   * decimal port number.
+   *
+   * Socktype and protocol values are then used to
+   * filter out the protocol records.
+   */
+  port = strtoul (servname, &ptr, 10);
+  if (*ptr || port > 65535)
+    {
+      if (flags & AI_NUMERICSERV)
+        return EAI_SERVICE;
+      port = -1;
+    }
+
+  struct gaih_servtuple head = { .next = NULL };
+  struct gaih_servtuple *st = &head;
 
+  const struct gaih_typeproto *tp;
+  bool socktype_found = false;
+  for (tp = gaih_inet_typeproto; tp->name[0]; tp++)
+    {
+      /* check socktype, protocol and GAI_PROTO_NOSERVICE */
+      if (socktype != 0 && socktype != tp->socktype)
+        continue;
+      socktype_found = true;
+      if (protocol != 0 && protocol != tp->protocol && !(tp->protoflag & GAI_PROTO_PROTOANY))
+        continue;
+      if (!(tp->protoflag & GAI_PROTO_NOSERVICE) && servname)
+        continue;
+
+      /* resolve servname if needed, check port */
+      int st_port = port;
+      if (st_port < 0)
+        st_port = getportbyname (servname, tp->name);
+      if (st_port < 0)
+        continue;
+
+      st = st->next = malloc (sizeof (struct gaih_servtuple));
+      if (!st)
+        {
+          free_service_list (head.next);
+          return EAI_MEMORY;
+        }
+      st->socktype = tp->socktype;
+      st->protocol = (tp->protoflag & GAI_PROTO_PROTOANY ? protocol : tp->protocol);
+      st->port = st_port;
+    }
+
+  /* POSIX1-2008:
+   *
+   * [EAI_SOCKTYPE] The intended socket type was not recognized.
+   * [EAI_SERVICE] The service passed was not recognized for the specified socket type.
+   *
+   * Actually, POSIX is a bit unclear as it doesn't define EAI_PROTOCOL and doesn't
+   * specify what error code should be used for unrecognized protocol.
+   */
+  if (!head.next)
+    return socktype_found ? -EAI_SERVICE : -EAI_SOCKTYPE;
+
+  *servtuple = head.next;
   return 0;
 }
 
@@ -253,7 +341,6 @@ gaih_inet_serv (const char *servicename, const struct gaih_typeproto *tp,
     }									      \
  }
 
-
 typedef enum nss_status (*nss_gethostbyname4_r)
   (const char *name, struct gaih_addrtuple **pat,
    char *buffer, size_t buflen, int *errnop,
@@ -267,134 +354,23 @@ typedef enum nss_status (*nss_getcanonname_r)
    int *errnop, int *h_errnop);
 extern service_user *__nss_hosts_database attribute_hidden;
 
-
 static int
-gaih_inet (const char *name, const struct gaih_service *service,
-	   const struct addrinfo *req, struct addrinfo **pai,
-	   unsigned int *naddrs)
+getaddrinfo_inet (const char *name, const char *servname,
+                  const struct addrinfo *req, struct addrinfo **pai,
+                  unsigned int *naddrs)
 {
-  const struct gaih_typeproto *tp = gaih_inet_typeproto;
-  struct gaih_servtuple *st = (struct gaih_servtuple *) &nullserv;
   struct gaih_addrtuple *at = NULL;
   int rc;
   bool got_ipv6 = false;
   const char *canon = NULL;
   const char *orig_name = name;
   size_t alloca_used = 0;
+  int error;
 
-  if (req->ai_protocol || req->ai_socktype)
-    {
-      ++tp;
-
-      while (tp->name[0]
-	     && ((req->ai_socktype != 0 && req->ai_socktype != tp->socktype)
-		 || (req->ai_protocol != 0
-		     && !(tp->protoflag & GAI_PROTO_PROTOANY)
-		     && req->ai_protocol != tp->protocol)))
-	++tp;
-
-      if (! tp->name[0])
-	{
-	  if (req->ai_socktype)
-	    return EAI_SOCKTYPE;
-	  else
-	    return EAI_SERVICE;
-	}
-    }
-
-  int port = 0;
-  if (service != NULL)
-    {
-      if ((tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
-	return EAI_SERVICE;
-
-      if (service->num < 0)
-	{
-	  if (tp->name[0])
-	    {
-	      st = (struct gaih_servtuple *)
-		alloca_account (sizeof (struct gaih_servtuple), alloca_used);
-
-	      if ((rc = gaih_inet_serv (service->name, tp, req, st)))
-		return rc;
-	    }
-	  else
-	    {
-	      struct gaih_servtuple **pst = &st;
-	      for (tp++; tp->name[0]; tp++)
-		{
-		  struct gaih_servtuple *newp;
-
-		  if ((tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
-		    continue;
-
-		  if (req->ai_socktype != 0
-		      && req->ai_socktype != tp->socktype)
-		    continue;
-		  if (req->ai_protocol != 0
-		      && !(tp->protoflag & GAI_PROTO_PROTOANY)
-		      && req->ai_protocol != tp->protocol)
-		    continue;
-
-		  newp = (struct gaih_servtuple *)
-		    alloca_account (sizeof (struct gaih_servtuple),
-				    alloca_used);
-
-		  if ((rc = gaih_inet_serv (service->name, tp, req, newp)))
-		    {
-		      if (rc)
-			continue;
-		      return rc;
-		    }
-
-		  *pst = newp;
-		  pst = &(newp->next);
-		}
-	      if (st == (struct gaih_servtuple *) &nullserv)
-		return EAI_SERVICE;
-	    }
-	}
-      else
-	{
-	  port = htons (service->num);
-	  goto got_port;
-	}
-    }
-  else
-    {
-    got_port:
-
-      if (req->ai_socktype || req->ai_protocol)
-	{
-	  st = alloca_account (sizeof (struct gaih_servtuple), alloca_used);
-	  st->next = NULL;
-	  st->socktype = tp->socktype;
-	  st->protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
-			  ? req->ai_protocol : tp->protocol);
-	  st->port = port;
-	}
-      else
-	{
-	  /* Neither socket type nor protocol is set.  Return all socket types
-	     we know about.  */
-	  struct gaih_servtuple **lastp = &st;
-	  for (++tp; tp->name[0]; ++tp)
-	    if (tp->defaultflag)
-	      {
-		struct gaih_servtuple *newp;
-
-		newp = alloca_account (sizeof (struct gaih_servtuple),
-				       alloca_used);
-		newp->next = NULL;
-		newp->socktype = tp->socktype;
-		newp->protocol = tp->protocol;
-		newp->port = port;
-
-		*lastp = newp;
-		lastp = &newp->next;
-	      }
-	}
-    }
+  struct gaih_servtuple *st;
+  if ((error = get_service_list (servname, req->ai_socktype, req->ai_protocol,
+                                 req->ai_flags & AI_NUMERICSERV, &st)))
+    return error;
 
   bool malloc_name = false;
   bool malloc_addrmem = false;
@@ -424,12 +400,13 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	  rc = __idna_to_ascii_lz (name, &p, idn_flags);
 	  if (rc != IDNA_SUCCESS)
 	    {
-	      /* No need to jump to free_and_return here.  */
 	      if (rc == IDNA_MALLOC_ERROR)
-		return EAI_MEMORY;
-	      if (rc == IDNA_DLOPEN_ERROR)
-		return EAI_SYSTEM;
-	      return EAI_IDN_ENCODE;
+                result = EAI_MEMORY;
+              else if (rc == IDNA_DLOPEN_ERROR)
+                result = EAI_SYSTEM;
+              else
+                result = EAI_IDN_ENCODE;
+              goto free_and_return;
 	    }
 	  /* In case the output string is the same as the input string
 	     no new string has been allocated.  */
@@ -491,7 +468,8 @@ gaih_inet (const char *name, const struct gaih_service *service,
 			if (namebuf == NULL)
 			  {
 			    assert (!malloc_name);
-			    return EAI_MEMORY;
+                            result = EAI_MEMORY;
+                            goto free_and_return;
 			  }
 			malloc_namebuf = true;
 		      }
@@ -1260,7 +1238,8 @@ gaih_inet (const char *name, const struct gaih_service *service,
       }
   }
 
- free_and_return:
+free_and_return:
+  free_service_list (st);
   if (malloc_name)
     free ((char *) name);
   if (malloc_addrmem)
@@ -2313,7 +2292,6 @@ getaddrinfo (const char *name, const char *service,
   int i = 0;
   int nresults = 0;
   struct addrinfo *p = NULL;
-  struct gaih_service gaih_service, *pservice;
   struct addrinfo local_hints;
 
   if (name != NULL && name[0] == '*' && name[1] == 0)
@@ -2376,32 +2354,11 @@ getaddrinfo (const char *name, const char *service,
 	}
     }
 
-  if (service && service[0])
-    {
-      char *c;
-      gaih_service.name = service;
-      gaih_service.num = strtoul (gaih_service.name, &c, 10);
-      if (*c != '\0')
-	{
-	  if (hints->ai_flags & AI_NUMERICSERV)
-	    {
-	      __free_in6ai (in6ai);
-	      return EAI_NONAME;
-	    }
-
-	  gaih_service.num = -1;
-	}
-
-      pservice = &gaih_service;
-    }
-  else
-    pservice = NULL;
-
   if (hints->ai_family == AF_UNSPEC || hints->ai_family == AF_INET
       || hints->ai_family == AF_INET6)
     {
       int error;
-      if ((error = gaih_inet (name, pservice, hints, &p, &nresults)))
+      if ((error = getaddrinfo_inet (name, service, hints, &p, &nresults)))
 	{
 	  freeaddrinfo (p);
 	  __free_in6ai (in6ai);