inet: Add __inet6_scopeid_pton function [BZ #20611]

__inet6_scopeid_pton implements strict validation of numeric scope IDs.
Use it in getaddrinfo and __res_vinit.

ChangeLog

@@ -1,3 +1,15 @@
+2016-09-15  Florian Weimer  <fweimer@redhat.com>
+
+	[BZ #20611]
+	* inet/Makefile (routines): Add inet6_scopeid_pton.
+	(tests): Add tst-inet6_scopeid_pton.
+	* inet/inet6_scopeid_pton.c: New file.
+	* inet/net-internal.h: Likewise.
+	* inet/tst-inet6_scopeid_pton.c: New test.
+	* inet/Versions (GLIBC_PRIVATE): Add __inet6_scopeid_pton.
+	* resolv/res_init.c (__res_vinit): Use __inet6_scopeid_pton.
+	* sysdeps/posix/getaddrinfo.c (gaih_inet): Likewise.
+
 2016-09-14  Florian Weimer  <fweimer@redhat.com>
 
 	Remove support for compiling wrappers with PTW.

inet/Makefile

@@ -44,13 +44,15 @@ routines := htonl htons		\
 	    getaliasent_r getaliasent getaliasname getaliasname_r \
 	    in6_addr getnameinfo if_index ifaddrs inet6_option \
 	    getipv4sourcefilter setipv4sourcefilter \
-	    getsourcefilter setsourcefilter inet6_opt inet6_rth
+	    getsourcefilter setsourcefilter inet6_opt inet6_rth \
+	    inet6_scopeid_pton
 
 aux := check_pf check_native ifreq
 
 tests := htontest test_ifindex tst-ntoa tst-ether_aton tst-network \
 	 tst-gethnm test-ifaddrs bug-if1 test-inet6_opt tst-ether_line \
-	 tst-getni1 tst-getni2 tst-inet6_rth tst-checks tst-sockaddr
+	 tst-getni1 tst-getni2 tst-inet6_rth tst-checks tst-sockaddr \
+	 tst-inet6_scopeid_pton
 
 include ../Rules
 

inet/Versions

@@ -85,5 +85,8 @@ libc {
     # functions used in other libraries
     __internal_endnetgrent; __internal_getnetgrent_r;
     __internal_setnetgrent;
+
+    # Used from nscd.
+    __inet6_scopeid_pton;
   }
 }

inet/inet6_scopeid_pton.c

@@ -0,0 +1,63 @@
+/* Convert an IPv6 scope ID from text to the internal representation.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <net-internal.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <locale.h>
+#include <net/if.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+/* Parse SOURCE as a scope ID for ADDRESS.  Return 0 on success and -1
+   on error.  */
+internal_function int
+__inet6_scopeid_pton (const struct in6_addr *address, const char *scope,
+                      uint32_t *result)
+{
+  if (IN6_IS_ADDR_LINKLOCAL (address)
+      || IN6_IS_ADDR_MC_LINKLOCAL (address))
+    {
+      uint32_t number = __if_nametoindex (scope);
+      if (number != 0)
+        {
+          *result = number;
+          return 0;
+        }
+    }
+
+  if (isdigit_l (scope[0], _nl_C_locobj_ptr))
+    {
+      char *end;
+      unsigned long long number
+        = ____strtoull_l_internal (scope, &end, /*base */ 10, /* group */ 0,
+                                   _nl_C_locobj_ptr);
+      if (*end == '\0' && number <= UINT32_MAX)
+        {
+          *result = number;
+          return 0;
+        }
+    }
+
+  __set_errno (EINVAL);
+  return -1;
+}
+
+libc_hidden_def (__inet6_scopeid_pton)

inet/net-internal.h

@@ -0,0 +1,30 @@
+/* Network-related functions for internal library use.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _NET_INTERNAL_H
+#define _NET_INTERNAL_H 1
+
+#include <arpa/inet.h>
+#include <stdint.h>
+
+int __inet6_scopeid_pton (const struct in6_addr *address,
+                          const char *scope, uint32_t *result)
+  internal_function attribute_hidden;
+libc_hidden_proto (__inet6_scopeid_pton)
+
+#endif /* _NET_INTERNAL_H */

inet/tst-inet6_scopeid_pton.c

@@ -0,0 +1,131 @@
+/* Tests for __inet6_scopeid_pton.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <arpa/inet.h>
+#include <inttypes.h>
+#include <net-internal.h>
+#include <net/if.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/* An interface which is known to the system.  */
+static const char *interface_name;
+static uint32_t interface_index;
+
+/* Initiale the variables above.  */
+static void
+setup_interface (void)
+{
+  struct if_nameindex *list = if_nameindex ();
+  if (list != NULL && list[0].if_index != 0 && list[0].if_name[0] != '\0')
+    {
+      interface_name = list[0].if_name;
+      interface_index = list[0].if_index;
+    }
+}
+
+/* Convert ADDRESS to struct in6_addr.  */
+static struct in6_addr
+from_string (const char *address)
+{
+  struct in6_addr addr;
+  if (inet_pton (AF_INET6, address, &addr) != 1)
+    {
+      printf ("error: inet_pton (\"%s\") failed\n", address);
+      exit (1);
+    }
+  return addr;
+}
+
+/* Check a single address were we expected a failure.  */
+static void
+expect_failure (const char *address, const char *scope)
+{
+  struct in6_addr addr = from_string (address);
+  uint32_t result = 1234;
+  if (__inet6_scopeid_pton (&addr, scope, &result) == 0)
+    {
+      printf ("error: unexpected success for %s%%%s\n",
+              address, scope);
+      exit (1);
+    }
+  if (result != 1234)
+    {
+      printf ("error: unexpected result update for %s%%%s\n",
+              address, scope);
+      exit (1);
+    }
+}
+
+/* Check a single address were we expected a success.  */
+static void
+expect_success (const char *address, const char *scope, uint32_t expected)
+{
+  struct in6_addr addr = from_string (address);
+  uint32_t actual = expected + 1;
+  if (__inet6_scopeid_pton (&addr, scope, &actual) != 0)
+    {
+      printf ("error: unexpected failure for %s%%%s\n",
+              address, scope);
+      exit (1);
+    }
+  if (actual != expected)
+    {
+      printf ("error: unexpected result for for %s%%%s\n",
+              address, scope);
+      printf ("  expected: %" PRIu32 "\n", expected);
+      printf ("  actual:   %" PRIu32 "\n", actual);
+      exit (1);
+    }
+}
+
+static int
+do_test (void)
+{
+  setup_interface ();
+
+  static const char *test_addresses[]
+    = { "::", "::1", "2001:db8::1", NULL };
+  for (int i = 0; test_addresses[i] != NULL; ++i)
+    {
+      expect_success (test_addresses[i], "0", 0);
+      expect_success (test_addresses[i], "5555", 5555);
+
+      expect_failure (test_addresses[i], "");
+      expect_failure (test_addresses[i], "-1");
+      expect_failure (test_addresses[i], "-99");
+      expect_failure (test_addresses[i], "037777777777");
+      expect_failure (test_addresses[i], "0x");
+      expect_failure (test_addresses[i], "0x1");
+    }
+
+  if (interface_name != NULL)
+    {
+      expect_success ("fe80::1", interface_name, interface_index);
+      expect_success ("ff02::1", interface_name, interface_index);
+      expect_failure ("::", interface_name);
+      expect_failure ("::1", interface_name);
+      expect_failure ("ff01::1", interface_name);
+      expect_failure ("2001:db8::1", interface_name);
+    }
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"

resolv/res_init.c

@@ -81,6 +81,7 @@
 #include <sys/socket.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <inet/net-internal.h>
 
 #include <not-cancel.h>
 
@@ -283,26 +284,12 @@ __res_vinit(res_state statp, int preinit) {
 				sa6->sin6_flowinfo = 0;
 				sa6->sin6_addr = a6;
 
-				if (__glibc_likely (el == NULL))
-				    sa6->sin6_scope_id = 0;
-				else {
-				    int try_numericscope = 1;
-				    if (IN6_IS_ADDR_LINKLOCAL (&a6)
-					|| IN6_IS_ADDR_MC_LINKLOCAL (&a6)) {
-					sa6->sin6_scope_id
-					  = __if_nametoindex (el + 1);
-					if (sa6->sin6_scope_id != 0)
-					    try_numericscope = 0;
-				    }
-
-				    if (try_numericscope) {
-					char *end;
-					sa6->sin6_scope_id
-					  = (uint32_t) strtoul (el + 1, &end,
-								10);
-					if (*end != '\0')
-					    sa6->sin6_scope_id = 0;
-				    }
+				sa6->sin6_scope_id = 0;
+				if (__glibc_likely (el != NULL)) {
+				  /* Ignore errors, for backwards
+				     compatibility.  */
+				  (void) __inet6_scopeid_pton
+				    (&a6, el + 1, &sa6->sin6_scope_id);
 				}
 
 				statp->nsaddr_list[nserv].sin_family = 0;

sysdeps/posix/getaddrinfo.c

@@ -82,6 +82,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <nscd/nscd_proto.h>
 #include <resolv/res_hconf.h>
 #include <scratch_buffer.h>
+#include <inet/net-internal.h>
 
 #ifdef HAVE_LIBIDN
 extern int __idna_to_ascii_lz (const char *input, char **output, int flags);
@@ -570,31 +571,13 @@ gaih_inet (const char *name, const struct gaih_service *service,
 		  goto free_and_return;
 		}
 
-	      if (scope_delim != NULL)
+	      if (scope_delim != NULL
+		  && __inet6_scopeid_pton ((struct in6_addr *) at->addr,
+					   scope_delim + 1,
+					   &at->scopeid) != 0)
 		{
-		  int try_numericscope = 0;
-		  if (IN6_IS_ADDR_LINKLOCAL (at->addr)
-		      || IN6_IS_ADDR_MC_LINKLOCAL (at->addr))
-		    {
-		      at->scopeid = if_nametoindex (scope_delim + 1);
-		      if (at->scopeid == 0)
-			try_numericscope = 1;
-		    }
-		  else
-		    try_numericscope = 1;
-
-		  if (try_numericscope != 0)
-		    {
-		      char *end;
-		      assert (sizeof (uint32_t) <= sizeof (unsigned long));
-		      at->scopeid = (uint32_t) strtoul (scope_delim + 1, &end,
-							10);
-		      if (*end != '\0')
-			{
-			  result = -EAI_NONAME;
-			  goto free_and_return;
-			}
-		    }
+		  result = -EAI_NONAME;
+		  goto free_and_return;
 		}
 
 	      if (req->ai_flags & AI_CANONNAME)