iconv: Revert steps array reference counting changes

The changes introduce a memory leak for gconv steps arrays whose
first element is an internal conversion, which has a fixed
reference count which is not decremented.  As a result, after the
change in commit 50ce3eae5ba304650459d4441d7d246a7cefc26f, the steps
array is never freed, resulting in an unbounded memory leak.

This reverts commit 50ce3eae5ba304650459d4441d7d246a7cefc26f
("gconv: Check reference count in __gconv_release_cache
[BZ #24677]") and commit 7e740ab2e7be7d83b75513aa406e0b10875f7f9c
("libio: Fix gconv-related memory leak [BZ #24583]").  It
reintroduces bug 24583.  (Bug 24677 was just a regression caused by
the second commit.)

8 files changed, 31 insertions, 132 deletions

diff --git a/ChangeLog b/ChangeLog
index 6b46bfa..1d9d50c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2019-07-31  Florian Weimer  <fweimer@redhat.com>
+
+	[BZ #24583]
+	[BZ #24677]
+	iconv, libio: Revert reference counting changes.
+	* iconv/gconv_cache.c (__gconv_release_cache): Unconditionally
+	free the steps array.
+	* libio/Makefile (tests): Remove tst-wfile-gconv.
+	(tests-container): Do not add tst-wfile-ascii.
+	(tst-wfile-gconv-ENV): Do not set.
+	(generated): Do not add tst-wfile-gconv.mtrace,
+	tst-wfile-gconv.check.
+	[($run-built-tests)] (tests-special): Do not add
+	tst-wfile-gconv-mem.out.
+	(tst-wfile-gconv.out, tst-wfile-gconv-mem.out): Remove targets.
+	* libio/iofclose.c (_IO_new_fclose): Call __gconv_release_step
+	instead of __wcsmbs_clone_conv.
+	* wcsmbs/wcsmbsload.c (__wcsmbs_clone_conv): Remove definition.
+	* wcsmbs/wcsmbsload.h (__wcsmbs_clone_conv): Remove declaration.
+
 2019-07-30  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/unix/sysv/linux/powerpc/powerpc32/swapcontext-common.S
diff --git a/iconv/gconv_cache.c b/iconv/gconv_cache.c
index 4db7287..9a456bf 100644
--- a/iconv/gconv_cache.c
+++ b/iconv/gconv_cache.c
@@ -446,12 +446,9 @@ __gconv_lookup_cache (const char *toset, const char *fromset,
 void
 __gconv_release_cache (struct __gconv_step *steps, size_t nsteps)
 {
-  /* The only thing we have to deallocate is the record with the
-     steps.  But do not do this if the reference counter is still
-     positive.  This can happen if the steps array was cloned by
-     __wcsmbs_clone_conv.  (The array elements have separate __counter
-     fields, but they are only out of sync temporarily.)  */
-  if (gconv_cache != NULL && steps->__counter == 0)
+  if (gconv_cache != NULL)
+    /* The only thing we have to deallocate is the record with the
+       steps.  */
     free (steps);
 }
 
diff --git a/libio/Makefile b/libio/Makefile
index 6e594b8..4a3637f 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -66,11 +66,7 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc   \
 	tst-fwrite-error tst-ftell-partial-wide tst-ftell-active-handler \
 	tst-ftell-append tst-fputws tst-bz22415 tst-fgetc-after-eof \
 	tst-sprintf-ub tst-sprintf-chk-ub tst-bz24051 tst-bz24153 \
-	tst-wfile-sync tst-wfile-gconv
-
-# This test tests interaction with the gconv cache.  Setting
-# GCONV_CACHE during out-of-container testing disables the cache.
-tests-container += tst-wfile-ascii
+	tst-wfile-sync
 
 tests-internal = tst-vtables tst-vtables-interposed tst-readline
 
@@ -173,12 +169,10 @@ test-fmemopen-ENV = MALLOC_TRACE=$(objpfx)test-fmemopen.mtrace
 tst-fopenloc-ENV = MALLOC_TRACE=$(objpfx)tst-fopenloc.mtrace
 tst-bz22415-ENV = MALLOC_TRACE=$(objpfx)tst-bz22415.mtrace
 tst-bz24228-ENV = MALLOC_TRACE=$(objpfx)tst-bz24228.mtrace
-tst-wfile-gconv-ENV = MALLOC_TRACE=$(objpfx)tst-wfile-gconv.mtrace
 
 generated += test-fmemopen.mtrace test-fmemopen.check
 generated += tst-fopenloc.mtrace tst-fopenloc.check
 generated += tst-bz22415.mtrace tst-bz22415.check
-generated += tst-wfile-gconv.mtrace tst-wfile-gconv.check
 
 aux	:= fileops genops stdfiles stdio strops
 
@@ -194,8 +188,7 @@ shared-only-routines = oldiofopen oldiofdopen oldiofclose oldfileops	\
 
 ifeq ($(run-built-tests),yes)
 tests-special += $(objpfx)test-freopen.out $(objpfx)test-fmemopen-mem.out \
-		 $(objpfx)tst-bz22415-mem.out \
-		 $(objpfx)tst-wfile-gconv-mem.out
+		 $(objpfx)tst-bz22415-mem.out
 ifeq (yes,$(build-shared))
 # Run tst-fopenloc-cmp.out and tst-openloc-mem.out only if shared
 # library is enabled since they depend on tst-fopenloc.out.
@@ -229,7 +222,6 @@ $(objpfx)tst-ungetwc2.out: $(gen-locales)
 $(objpfx)tst-widetext.out: $(gen-locales)
 $(objpfx)tst_wprintf2.out: $(gen-locales)
 $(objpfx)tst-wfile-sync.out: $(gen-locales)
-$(objpfx)tst-wfile-gconv.out: $(gen-locales)
 endif
 
 $(objpfx)test-freopen.out: test-freopen.sh $(objpfx)test-freopen
@@ -257,7 +249,3 @@ $(objpfx)tst-bz22415-mem.out: $(objpfx)tst-bz22415.out
 $(objpfx)tst-bz24228-mem.out: $(objpfx)tst-bz24228.out
 	$(common-objpfx)malloc/mtrace $(objpfx)tst-bz24228.mtrace > $@; \
 	$(evaluate-test)
-
-$(objpfx)tst-wfile-gconv-mem.out: $(objpfx)tst-wfile-gconv.out
-	$(common-objpfx)malloc/mtrace $(objpfx)tst-wfile-gconv.mtrace > $@; \
-	$(evaluate-test)
diff --git a/libio/iofclose.c b/libio/iofclose.c
index c03c6cf..8a80dd0 100644
--- a/libio/iofclose.c
+++ b/libio/iofclose.c
@@ -26,8 +26,8 @@
 
 #include "libioP.h"
 #include <stdlib.h>
+#include "../iconv/gconv_int.h"
 #include <shlib-compat.h>
-#include <wcsmbs/wcsmbsload.h>
 
 int
 _IO_new_fclose (FILE *fp)
@@ -60,14 +60,11 @@ _IO_new_fclose (FILE *fp)
       /* This stream has a wide orientation.  This means we have to free
 	 the conversion functions.  */
       struct _IO_codecvt *cc = fp->_codecvt;
-      struct gconv_fcts conv =
-	{
-	 .towc = cc->__cd_in.__cd.__steps,
-	 .towc_nsteps = cc->__cd_in.__cd.__nsteps,
-	 .tomb = cc->__cd_out.__cd.__steps,
-	 .tomb_nsteps = cc->__cd_out.__cd.__nsteps,
-	};
-      __wcsmbs_close_conv (&conv);
+
+      __libc_lock_lock (__gconv_lock);
+      __gconv_release_step (cc->__cd_in.__cd.__steps);
+      __gconv_release_step (cc->__cd_out.__cd.__steps);
+      __libc_lock_unlock (__gconv_lock);
     }
   else
     {
diff --git a/libio/tst-wfile-ascii.c b/libio/tst-wfile-ascii.c
deleted file mode 100644
index 7514289..0000000
--- a/libio/tst-wfile-ascii.c
+++ /dev/null
@@ -1,56 +0,0 @@
-/* Test ASCII gconv module followed by cache initialization.
-   Copyright (C) 2019 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 <stdlib.h>
-#include <support/check.h>
-#include <support/support.h>
-#include <support/xstdio.h>
-#include <wchar.h>
-
-static int
-do_test (void)
-{
-  /* The test-in-container framework sets these environment variables.
-     The presence of GCONV_PATH invalidates this test.  */
-  unsetenv ("GCONV_PATH");
-  unsetenv ("LOCPATH");
-
-  /* Create the gconv module cache.  iconvconfig is in /sbin, which is
-     not on PATH.  */
-  {
-    char *iconvconfig = xasprintf ("%s/iconvconfig", support_sbindir_prefix);
-    TEST_COMPARE (system (iconvconfig), 0);
-  }
-
-  /* Use built-in ASCII gconv module, without triggering cache
-     initialization.  */
-  FILE *fp1 = xfopen ("/dev/zero", "r");
-  TEST_COMPARE (fwide (fp1, 1), 1);
-
-  /* Use non-ASCII gconv module and trigger gconv cache
-     initialization.  */
-  FILE *fp2 = xfopen ("/dev/zero", "r,ccs=UTF-8");
-  TEST_COMPARE (fwide (fp2, 0), 1);
-
-  xfclose (fp1);
-  xfclose (fp2);
-
-  return 0;
-}
-
-#include <support/test-driver.c>
diff --git a/libio/tst-wfile-gconv.c b/libio/tst-wfile-gconv.c
deleted file mode 100644
index de603b3..0000000
--- a/libio/tst-wfile-gconv.c
+++ /dev/null
@@ -1,36 +0,0 @@
-/* Test that non-built-in gconv modules do not cause memory leak (bug 24583).
-   Copyright (C) 2019 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 <locale.h>
-#include <mcheck.h>
-#include <support/check.h>
-#include <support/xstdio.h>
-
-static int
-do_test (void)
-{
-  mtrace ();
-
-  TEST_VERIFY_EXIT (setlocale (LC_ALL, "ja_JP.EUC-JP") != NULL);
-  xfclose (xfopen ("/etc/passwd", "r,ccs=UTF-8"));
-  xfclose (xfopen ("/etc/passwd", "r"));
-
-  return 0;
-}
-
-#include <support/test-driver.c>
diff --git a/wcsmbs/wcsmbsload.c b/wcsmbs/wcsmbsload.c
index 840d4ab..6648365 100644
--- a/wcsmbs/wcsmbsload.c
+++ b/wcsmbs/wcsmbsload.c
@@ -279,13 +279,3 @@ _nl_cleanup_ctype (struct __locale_data *locale)
       free ((char *) data);
     }
 }
-
-/* Free the specified conversion functions (but not CONV itself).  */
-void
-__wcsmbs_close_conv (struct gconv_fcts *conv)
-{
-  if (conv->towc != &to_wc)
-      __gconv_close_transform (conv->towc, conv->towc_nsteps);
-  if (conv->tomb != &to_mb)
-      __gconv_close_transform (conv->tomb, conv->tomb_nsteps);
-}
diff --git a/wcsmbs/wcsmbsload.h b/wcsmbs/wcsmbsload.h
index c2fffbd..6ccad4b 100644
--- a/wcsmbs/wcsmbsload.h
+++ b/wcsmbs/wcsmbsload.h
@@ -51,7 +51,6 @@ extern int __wcsmbs_named_conv (struct gconv_fcts *copy, const char *name)
 /* Function used for the `private.cleanup' hook.  */
 extern void _nl_cleanup_ctype (struct __locale_data *) attribute_hidden;
 
-extern void __wcsmbs_close_conv (struct gconv_fcts *conv) attribute_hidden;
 
 #include <iconv/gconv_int.h>