[PATCH] Don't require DNS labels to be host names

[Andreas Schwab]

2010-10-26  Andreas Schwab  <schwab@redhat.com>

	[BZ #12154]
	* resolv/nss_dns/dns-host.c (getanswer_r): Don't require DNS
	labels to be host names.
	(gaih_getanswer_slice): Likewise.
---
 resolv/nss_dns/dns-host.c |   42 ++++++++++++++++++++++++++++--------------
 1 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
index 8592183..19f6dab 100644
--- a/resolv/nss_dns/dns-host.c
+++ b/resolv/nss_dns/dns-host.c
@@ -716,7 +716,7 @@ getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype,
 	  n = -1;
 	}
 
-      if (__builtin_expect (n < 0 || (*name_ok) (bp) == 0, 0))
+      if (__builtin_expect (n < 0 || res_dnok (bp) == 0, 0))
 	{
 	  ++had_error;
 	  continue;
@@ -746,25 +746,29 @@ getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype,
 
       if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME)
 	{
-	  if (ap >= &host_data->aliases[MAX_NR_ALIASES - 1])
-	    continue;
 	  n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf);
-	  if (__builtin_expect (n < 0 || (*name_ok) (tbuf) == 0, 0))
+	  if (__builtin_expect (n < 0 || res_dnok (tbuf) == 0, 0))
 	    {
 	      ++had_error;
 	      continue;
 	    }
 	  cp += n;
-	  /* Store alias.  */
-	  *ap++ = bp;
-	  n = strlen (bp) + 1;		/* For the \0.  */
-	  if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN)
+	  /* Ignore aliases that are not valid host names.  */
+	  if (res_hnok (bp))
 	    {
-	      ++had_error;
-	      continue;
+	      if (ap >= &host_data->aliases[MAX_NR_ALIASES - 1])
+		continue;
+	      /* Store alias.  */
+	      *ap++ = bp;
+	      n = strlen (bp) + 1;		/* For the \0.  */
+	      if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN)
+		{
+		  ++had_error;
+		  continue;
+		}
+	      bp += n;
+	      linebuflen -= n;
 	    }
-	  bp += n;
-	  linebuflen -= n;
 	  /* Get canonical name.  */
 	  n = strlen (tbuf) + 1;	/* For the \0.  */
 	  if (__builtin_expect (n > linebuflen, 0))
@@ -892,6 +896,11 @@ getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype,
 #endif
 	case T_A:
 	case T_AAAA:
+	  if (res_hnok (bp) == 0)
+	    {
+	      had_error++;
+	      break;
+	    }
 	  if (__builtin_expect (strcasecmp (result->h_name, bp), 0) != 0)
 	    {
 	      syslog (LOG_NOTICE | LOG_AUTH, AskedForGot, result->h_name, bp);
@@ -1045,7 +1054,7 @@ gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname,
 
 	  n = -1;
 	}
-      if (__builtin_expect (n < 0 || res_hnok (buffer) == 0, 0))
+      if (__builtin_expect (n < 0 || res_dnok (buffer) == 0, 0))
 	{
 	  ++had_error;
 	  continue;
@@ -1084,7 +1093,7 @@ gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname,
 	{
 	  char tbuf[MAXDNAME];
 	  n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf);
-	  if (__builtin_expect (n < 0 || res_hnok (tbuf) == 0, 0))
+	  if (__builtin_expect (n < 0 || res_dnok (tbuf) == 0, 0))
 	    {
 	      ++had_error;
 	      continue;
@@ -1163,6 +1172,11 @@ gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname,
 
       if (*firstp)
 	{
+	  if (res_hnok (canon ?: h_name) == 0)
+	    {
+	      ++had_error;
+	      continue;
+	    }
 	  if (ttl != 0 && ttlp != NULL)
 	    *ttlp = ttl;
 
-- 
1.7.2.3


-- 
Andreas Schwab, schwab@redhat.com
GPG Key fingerprint = D4E8 DBE3 3813 BB5D FA84  5EC7 45C6 250E 6F00 984E
"And now for something completely different."