[PATCH v10] locale: memory leak in newlocale [BZ #25770]
Adhemerval Zanella Netto
adhemerval.zanella@linaro.org
Wed Aug 27 15:44:02 GMT 2025
On 06/06/25 03:42, Dmitry Kovalenko wrote:
> From 59ae6a06afe6fb4963feb0b82e2bb673fc0ef153 Mon Sep 17 00:00:00 2001
> From: "d.kovalenko" <d.kovalenko@postgrespro.ru>
> Date: Fri, 6 Jun 2025 09:38:52 +0300
> Subject: [PATCH v10] locale: memory leak in newlocale [BZ #25770]
> To: libc-alpha@sourceware.org
> Cc: d.kovalenko@postgrespro.ru,fweimer@redhat.com,schwab@suse.de
>
> It is a fix for memory leak in the function 'newlocale' (the real name is __newlocale).
>
> There is not released a memory for the local buffer 'locale_path'.
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=25770
>
> ---
> Patch was tested on Ubuntu 24.04.
>
> My 'LOCPATH' environment variable is "/snap/code/193/usr/lib/locale".
>
> With an original (system) libc I have the following problem:
>
> #0 0x7d5c3aafc778 in realloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:85
> #1 0x7d5c394b05f2 in __argz_add_sep string/argz-addsep.c:34
> #2 0x7d5c39439bdb in __newlocale locale/newlocale.c:111
> #3 0x7d5c370e58fc (/lib/x86_64-linux-gnu/libp11-kit.so.0+0x1098fc) (BuildId: 1cbcd6ac7e0ff0259eb3acc14d556d2c1ec00cdc)
> #4 0x7d5c3b14571e in call_init elf/dl-init.c:74
> #5 0x7d5c3b145823 in call_init elf/dl-init.c:120
> #6 0x7d5c3b145823 in _dl_init elf/dl-init.c:121
> #7 0x7d5c3b15f59f (/lib64/ld-linux-x86-64.so.2+0x1f59f) (BuildId: 1c8db5f83bba514f8fd5f1fb6d7be975be1bb855)
>
> SUMMARY: AddressSanitizer: 46 byte(s) leaked in 1 allocation(s).
>
> When I run with my corrected libc, through runtest.sh <my-application>, all is OK.
>
> Signed-off-by: Dmitry Kovalenko <d.kovalenko@postgrespro.ru>
>
> Co-authored-by: Florian Weimer <fweimer@redhat.com>
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>
> ---------------- History
>
> ---- v10
> - __newlocale_1 is updated.
> - the initial debug checks of locale_path_ptr are removed
> - the initial initialization of locale_path_ptr with NULL is added
>
> ---- v9
> * A test is refactored (TEST_COMPARE, TEST_VERIFY_EXIT)
>
> ---- v8
> * A code style in test is corrected.
> * A error message in test is corrected.
> * A useless code from makefile is removed.
>
> newlocale.c did not change.
>
> ---- v7
> * A code style is corrected.
> * Test LOCPATH is "."
> * Test uses setenv instead putenv.
>
> ---- v6
> * A code style is corrected.
>
> ---- v5
> * A test is added.
>
> This test creates locale "POSIX" and works with "/usr/share/locale" folder.
>
> tst-newlocale-mem.out content:
> OLD: Memory not freed: ... (one block, 0x22 bytes)
> NEW: No memory leaks.
>
> Test OS is Ubuntu 24.04.
>
> ---- v4
> * A code style is corrected.
>
> ---- v3
> * The problems are fixed. Thanks to Florian Weimer.
>
> ---- v2
> * A simplification (__newlocale_1). An idea of Florian Weimer.
>
> ---- v1
> * An initial correction.
> ---
> locale/Makefile | 18 +++++++++++++++++
> locale/newlocale.c | 32 +++++++++++++++++++++++-------
> locale/tst-newlocale.c | 44 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 87 insertions(+), 7 deletions(-)
> create mode 100755 locale/tst-newlocale.c
>
> diff --git a/locale/Makefile b/locale/Makefile
> index 9d9c1a7691..70788df2f4 100644
> --- a/locale/Makefile
> +++ b/locale/Makefile
> @@ -47,6 +47,7 @@ tests = \
> tst-C-locale \
> tst-duplocale \
> tst-locname \
> + tst-newlocale \
> # tests
> tests-container = \
> tst-localedef-path-norm \
> @@ -133,6 +134,16 @@ GPERFFLAGS = -acCgopt -k1,2,5,9,$$ -L ANSI-C
>
> ifeq ($(run-built-tests),yes)
> tests-special += $(objpfx)tst-locale-locpath.out
> +ifeq ($(build-shared),yes)
> +ifneq ($(PERL),no)
> +generated += \
> + tst-newlocale.mtrace \
> + # generated
> +tests-special += \
> + $(objpfx)tst-newlocale-mem.out \
> + # tests-special
> +endif # $(PERL) == yes
> +endif # $(build-shared) == yes
> endif
>
> include ../Rules
> @@ -184,3 +195,10 @@ $(objpfx)tst-locale-locpath.out : tst-locale-locpath.sh $(objpfx)locale
> $(evaluate-test)
>
> $(objpfx)tst-localedef-path-norm: $(shared-thread-library)
> +
> +LDLIBS-tst-newlocale = $(shared-thread-library)
> +tst-newlocale-ENV = MALLOC_TRACE=$(objpfx)tst-newlocale.mtrace \
> + LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so
> +$(objpfx)tst-newlocale-mem.out: $(objpfx)tst-newlocale.out
> + $(common-objpfx)malloc/mtrace $(objpfx)tst-newlocale.mtrace > $@; \
> + $(evaluate-test)
> diff --git a/locale/newlocale.c b/locale/newlocale.c
> index d25a6038d3..9a5c2ddea2 100644
> --- a/locale/newlocale.c
> +++ b/locale/newlocale.c
> @@ -22,6 +22,7 @@
> #include <locale.h>
> #include <stdlib.h>
> #include <string.h>
> +#include <assert.h>
>
> #include "localeinfo.h"
>
> @@ -38,19 +39,21 @@ __libc_rwlock_define (extern , __libc_setlocale_lock attribute_hidden)
> } while (0)
>
>
> -locale_t
> -__newlocale (int category_mask, const char *locale, locale_t base)
> +static locale_t
> +__newlocale_1 (int category_mask, const char *locale, locale_t base,
> + char ** const locale_path_ptr)
> {
> /* Intermediate memory for result. */
> const char *newnames[__LC_LAST];
> struct __locale_struct result;
> locale_t result_ptr;
> - char *locale_path;
> size_t locale_path_len;
> const char *locpath_var;
> int cnt;
> size_t names_len;
>
> + *locale_path_ptr = NULL;
> +
> /* We treat LC_ALL in the same way as if all bits were set. */
> if (category_mask == 1 << LC_ALL)
> category_mask = (1 << __LC_LAST) - 1 - (1 << LC_ALL);
> @@ -98,19 +101,20 @@ __newlocale (int category_mask, const char *locale, locale_t base)
> `LOCPATH' must only be used when the binary has no SUID or SGID
> bit set. If using the default path, we tell _nl_find_locale
> by passing null and it can check the canonical locale archive. */
> - locale_path = NULL;
> locale_path_len = 0;
>
> locpath_var = getenv ("LOCPATH");
> if (locpath_var != NULL && locpath_var[0] != '\0')
> {
> if (__argz_create_sep (locpath_var, ':',
> - &locale_path, &locale_path_len) != 0)
> + locale_path_ptr, &locale_path_len) != 0)
> return NULL;
>
> - if (__argz_add_sep (&locale_path, &locale_path_len,
> + if (__argz_add_sep (locale_path_ptr, &locale_path_len,
> _nl_default_locale_path, ':') != 0)
> return NULL;
> +
> + assert (*locale_path_ptr != NULL);
> }
>
> /* Get the names for the locales we are interested in. We either
> @@ -166,7 +170,7 @@ __newlocale (int category_mask, const char *locale, locale_t base)
> {
> if ((category_mask & 1 << cnt) != 0)
> {
> - result.__locales[cnt] = _nl_find_locale (locale_path,
> + result.__locales[cnt] = _nl_find_locale (*locale_path_ptr,
> locale_path_len,
> cnt, &newnames[cnt]);
> if (result.__locales[cnt] == NULL)
> @@ -275,4 +279,18 @@ __newlocale (int category_mask, const char *locale, locale_t base)
>
> return result_ptr;
> }
> +
> +locale_t
> +__newlocale (int category_mask, const char *locale, locale_t base)
> +{
> + char *tmp_buffer = NULL;
> +
> + const locale_t result = __newlocale_1 (category_mask, locale,
> + base, &tmp_buffer);
> +
> + free (tmp_buffer);
> +
> + return result;
> +}
> +
> weak_alias (__newlocale, newlocale)
> diff --git a/locale/tst-newlocale.c b/locale/tst-newlocale.c
> new file mode 100755
> index 0000000000..5ba38586ff
> --- /dev/null
> +++ b/locale/tst-newlocale.c
> @@ -0,0 +1,44 @@
> +/* This test checks a memory leak in newlocal function [BZ #25770].
> + Copyright The GNU Toolchain Authors.
> + 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
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <support/check.h>
> +#include <mcheck.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <locale.h>
> +
> +static int
> +do_test (void)
> +{
> + mtrace ();
> +
> + /* We can use an any valid path here.
> + If setenv fails, the next part of test should still run okay. */
> + TEST_COMPARE (setenv ("LOCPATH", ".", 1), 0);
> +
> + {
> + locale_t const l = newlocale (1 << LC_CTYPE, "POSIX", NULL);
> + TEST_VERIFY_EXIT (l != NULL);
> +
> + freelocale (l);
> + }
> +
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
> --
> 2.43.0
>
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