Fix ucs4le_internal_loop in error case. [BZ #19726]

When converting from UCS4LE to INTERNAL, the input-value is checked for a too
large value and the iconv() call sets errno to EILSEQ. In this case the inbuf
argument of the iconv() call should point to the invalid character, but it
points to the beginning of the inbuf.
Thus this patch updates the pointers inptrp and outptrp before returning in
this error case.

This patch also adds a new testcase for this issue.
The new test was tested on a s390, power, intel machine.

ChangeLog:

	[BZ #19726]
	* iconv/gconv_simple.c (ucs4le_internal_loop): Update inptrp and
	outptrp in case of an illegal input.
	* iconv/tst-iconv6.c: New file.
	* iconv/Makefile (tests): Add tst-iconv6.

ChangeLog

@@ -1,3 +1,11 @@
+2016-05-25  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+	[BZ #19726]
+	* iconv/gconv_simple.c (ucs4le_internal_loop): Update inptrp and
+	outptrp in case of an illegal input.
+	* iconv/tst-iconv6.c: New file.
+	* iconv/Makefile (tests): Add tst-iconv6.
+
 2016-05-25  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
 	* sysdeps/s390/utf16-utf32-z9.c: Disable cu42 instruction and report

iconv/Makefile

@@ -42,7 +42,7 @@ CFLAGS-charmap.c = -DCHARMAP_PATH='"$(i18ndir)/charmaps"' \
 CFLAGS-linereader.c = -DNO_TRANSLITERATION
 CFLAGS-simple-hash.c = -I../locale
 
-tests	= tst-iconv1 tst-iconv2 tst-iconv3 tst-iconv4 tst-iconv5
+tests	= tst-iconv1 tst-iconv2 tst-iconv3 tst-iconv4 tst-iconv5 tst-iconv6
 
 others		= iconv_prog iconvconfig
 install-others-programs	= $(inst_bindir)/iconv

iconv/gconv_simple.c

@@ -638,6 +638,8 @@ ucs4le_internal_loop (struct __gconv_step *step,
 	      continue;
 	    }
 
+	  *inptrp = inptr;
+	  *outptrp = outptr;
 	  return __GCONV_ILLEGAL_INPUT;
 	}
 

iconv/tst-iconv6.c

@@ -0,0 +1,117 @@
+/* Testing ucs4le_internal_loop() in gconv_simple.c.
+   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 <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <inttypes.h>
+#include <iconv.h>
+#include <byteswap.h>
+
+static int
+do_test (void)
+{
+  iconv_t cd;
+  char *inptr;
+  size_t inlen;
+  char *outptr;
+  size_t outlen;
+  size_t n;
+  int e;
+  int result = 0;
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+  /* On big-endian machines, ucs4le_internal_loop() swaps the bytes before
+     error checking. Thus the input values has to be swapped.  */
+# define VALUE(val) bswap_32 (val)
+#else
+# define VALUE(val) val
+#endif
+  uint32_t inbuf[3] = { VALUE (0x41), VALUE (0x80000000), VALUE (0x42) };
+  uint32_t outbuf[3] = { 0, 0, 0 };
+
+  cd = iconv_open ("WCHAR_T", "UCS-4LE");
+  if (cd == (iconv_t) -1)
+    {
+      printf ("cannot convert from UCS4LE to wchar_t: %m\n");
+      return 1;
+    }
+
+  inptr = (char *) inbuf;
+  inlen = sizeof (inbuf);
+  outptr = (char *) outbuf;
+  outlen = sizeof (outbuf);
+
+  n = iconv (cd, &inptr, &inlen, &outptr, &outlen);
+  e = errno;
+
+  if (n != (size_t) -1)
+    {
+      printf ("incorrect iconv() return value: %zd, expected -1\n", n);
+      result = 1;
+    }
+
+  if (e != EILSEQ)
+    {
+      printf ("incorrect error value: %s, expected %s\n",
+	      strerror (e), strerror (EILSEQ));
+      result = 1;
+    }
+
+  if (inptr != (char *) &inbuf[1])
+    {
+      printf ("inptr=0x%p does not point to invalid character! Expected=0x%p\n"
+	      , inptr, &inbuf[1]);
+      result = 1;
+    }
+
+  if (inlen != sizeof (inbuf) - sizeof (uint32_t))
+    {
+      printf ("inlen=%zd != %zd\n"
+	      , inlen, sizeof (inbuf) - sizeof (uint32_t));
+      result = 1;
+    }
+
+  if (outptr != (char *) &outbuf[1])
+    {
+      printf ("outptr=0x%p does not point to invalid character in inbuf! "
+	      "Expected=0x%p\n"
+	      , outptr, &outbuf[1]);
+      result = 1;
+    }
+
+  if (outlen != sizeof (inbuf) - sizeof (uint32_t))
+    {
+      printf ("outlen=%zd != %zd\n"
+	      , outlen, sizeof (outbuf) - sizeof (uint32_t));
+      result = 1;
+    }
+
+  if (outbuf[0] != 0x41 || outbuf[1] != 0 || outbuf[2] != 0)
+    {
+      puts ("Characters conversion is incorrect!");
+      result = 1;
+    }
+
+  iconv_close (cd);
+
+  return result;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"