BZ#14498: fix infinite loop in nss_db_getservbyname

nss_db uses nss_files code for services, but a continue on protocol
mismatch that doesn't affect nss_files skipped the code that advanced
to the next db entry.  Any one of these changes would suffice to fix
it, but fixing both makes them both safer to reuse elsewhere.

for  ChangeLog

	[BZ #14498]
	* NEWS: Fixed.
	* nss/nss_db/db-XXX.c (_nss_db_get##name##_r): Update hidx
	after parsing line but before break_if_match.
	* nss/nss_files/files-service (DB_LOOKUP): Don't "continue;"
	if there is a protocol mismatch.

ChangeLog

@@ -1,3 +1,12 @@
+2014-11-21  Alexandre Oliva <aoliva@redhat.com>
+
+	[BZ #14498]
+	* NEWS: Fixed.
+	* nss/nss_db/db-XXX.c (_nss_db_get##name##_r): Update hidx
+	after parsing line but before break_if_match.
+	* nss/nss_files/files-service (DB_LOOKUP): Don't "continue;"
+	if there is a protocol mismatch.
+
 2014-11-21  Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>
 
 	* manual/sysinfo.texi (addmntent): It is actually MT-Safe,

NEWS

@@ -9,10 +9,10 @@ Version 2.21
 
 * The following bugs are resolved with this release:
 
-  6652, 12926, 14132, 14138, 14171, 15215, 15884, 17266, 17344, 17363,
-  17370, 17371, 17411, 17460, 17475, 17485, 17501, 17506, 17508, 17522,
-  17555, 17570, 17571, 17572, 17573, 17574, 17582, 17583, 17584, 17585,
-  17589, 17594, 17616, 17625.
+  6652, 12926, 14132, 14138, 14171, 14498, 15215, 15884, 17266, 17344,
+  17363, 17370, 17371, 17411, 17460, 17475, 17485, 17501, 17506, 17508,
+  17522, 17555, 17570, 17571, 17572, 17573, 17574, 17582, 17583, 17584,
+  17585, 17589, 17594, 17616, 17625.
 
 * CVE-2104-7817 The wordexp function could ignore the WRDE_NOCMD flag
   under certain input conditions resulting in the execution of a shell for

nss/nss_db/db-XXX.c

@@ -191,6 +191,12 @@ enum nss_status								      \
       char *p = memcpy (buffer, valstr, len);				      \
 									      \
       int err = parse_line (p, result, data, buflen, errnop EXTRA_ARGS);      \
+									      \
+      /* Advance before break_if_match, lest it uses continue to skip
+	 to the next entry.  */						      \
+      if ((hidx += hval2) >= header->dbs[i].hashsize)			      \
+	hidx -= header->dbs[i].hashsize;				      \
+									      \
       if (err > 0)							      \
 	{								      \
 	  status = NSS_STATUS_SUCCESS;					      \
@@ -203,9 +209,6 @@ enum nss_status								      \
 	  status = NSS_STATUS_TRYAGAIN;					      \
 	  break;							      \
 	}								      \
-									      \
-      if ((hidx += hval2) >= header->dbs[i].hashsize)			      \
-	hidx -= header->dbs[i].hashsize;				      \
     }									      \
 									      \
   if (status == NSS_STATUS_NOTFOUND)					      \

nss/nss_files/files-service.c

@@ -44,8 +44,11 @@ DB_LOOKUP (servbyname, ':',
 	   {
 	     /* Must match both protocol (if specified) and name.  */
 	     if (proto != NULL && strcmp (result->s_proto, proto))
-	       continue;
-	     LOOKUP_NAME (s_name, s_aliases)
+	       /* A continue statement here breaks nss_db, because it
+		bypasses advancing to the next db entry, and it
+		doesn't make nss_files any more efficient.  */;
+	     else
+	       LOOKUP_NAME (s_name, s_aliases)
 	   },
 	   const char *name, const char *proto)