ctype: Fallback initialization of TLS using relocations (bug 19341, bug 32483)

This ensures that the ctype data pointers in TLS are valid
in secondary namespaces even without initialization via
__ctype_init.

Reviewed-by: Frédéric Bérat <fberat@redhat.com>
(cherry picked from commit 2745db8dd3ec31045acd761b612516490085bc20)

diff --git a/NEWS b/NEWS
index 31ae240f882d62ab6c5580d269af560a98cb6532..2915312d26d7810cf58f646544e0add25f9403e4 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -40,6 +40,7 @@ The following CVEs were fixed in this release:
 
 The following bugs are resolved with this release:
 
+  [19341] ctype: Fallback initialization of TLS using relocations
   [19622] network: Support aliasing with struct sockaddr
   [27821] ungetc: Fix backup buffer leak on program exit
   [30081] resolv: Do not wait for non-existing second DNS response after error
@@ -103,6 +104,7 @@ The following bugs are resolved with this release:
   [32810] Crash on x86-64 if XSAVEC disable via tunable
   [32987] elf: Fix subprocess status handling for tst-dlopen-sgid
   [33185] Fix double-free after allocation failure in regcomp
+  [32483] ctype macros segfault in multithreaded programs with multiple libc.so
 \f
 Version 2.39
 

diff --git a/ctype/Makefile b/ctype/Makefile
index 3e09938bd1bb15229cbdb1f851dd8af5be13ddc2..b7cd5f2282b4511c9ac9a455fb6111ea905a8f7f 100644 (file)
--- a/ctype/Makefile
+++ b/ctype/Makefile
@@ -36,6 +36,23 @@ aux := ctype-info
 
 tests := \
   test_ctype \
+  tst-ctype-tls-dlmopen \
+  tst-ctype-tls-dlopen-static \
   # tests
 
+tests-static := \
+  tst-ctype-tls-dlopen-static \
+  # tests-static
+
+modules-names := \
+  tst-ctype-tls-mod \
+  # modules-names
+
 include ../Rules
+
+$(objpfx)tst-ctype-tls-dlmopen: $(shared-thread-library)
+$(objpfx)tst-ctype-tls-dlmopen.out: $(objpfx)tst-ctype-tls-mod.so
+$(objpfx)tst-ctype-tls-dlopen-static: $(static-thread-library)
+$(objpfx)tst-ctype-tls-dlopen-static.out: $(objpfx)tst-ctype-tls-mod.so
+tst-ctype-tls-dlopen-static-ENV = \
+  LD_LIBRARY_PATH=$(ld-library-path):$(common-objpfx):$(common-objpfx)elf

diff --git a/ctype/ctype-info.c b/ctype/ctype-info.c
index 94e312d91ff7632364f1a36636bc5a2e9d3b8e10..621bd4239c8b4c2173cc1f0f3b71a6b5705ac9ea 100644 (file)
--- a/ctype/ctype-info.c
+++ b/ctype/ctype-info.c
@@ -19,9 +19,17 @@
 #include <ctype.h>
 #include <locale/localeinfo.h>
 
-__thread const uint16_t * __libc_tsd_CTYPE_B;
-__thread const int32_t * __libc_tsd_CTYPE_TOLOWER;
-__thread const int32_t * __libc_tsd_CTYPE_TOUPPER;
+/* Fallback initialization using relocations.  See the _nl_C_locobj
+   initializers in locale/xlocale.c.  Usually, this is overwritten by
+   __ctype_init before user code runs, but this does not happen for
+   threads in secondary namespaces.  With the initializers, secondary
+   namespaces at least get locale data from the C locale.  */
+__thread const uint16_t * __libc_tsd_CTYPE_B
+  = (const uint16_t *) _nl_C_LC_CTYPE_class + 128;
+__thread const int32_t * __libc_tsd_CTYPE_TOLOWER
+  = (const int32_t *) _nl_C_LC_CTYPE_tolower + 128;
+__thread const int32_t * __libc_tsd_CTYPE_TOUPPER
+  = (const int32_t *) _nl_C_LC_CTYPE_toupper + 128;
 
 
 void

diff --git a/ctype/tst-ctype-tls-dlmopen.c b/ctype/tst-ctype-tls-dlmopen.c
new file mode 100644 (file)
index 0000000..f7eeb65
--- /dev/null
+++ b/ctype/tst-ctype-tls-dlmopen.c
@@ -0,0 +1,2 @@
+#define DO_STATIC_TEST 0
+#include "tst-ctype-tls-skeleton.c"

diff --git a/ctype/tst-ctype-tls-dlopen-static.c b/ctype/tst-ctype-tls-dlopen-static.c
new file mode 100644 (file)
index 0000000..c2c09c3
--- /dev/null
+++ b/ctype/tst-ctype-tls-dlopen-static.c
@@ -0,0 +1,2 @@
+#define DO_STATIC_TEST 1
+#include "tst-ctype-tls-skeleton.c"

diff --git a/ctype/tst-ctype-tls-mod.c b/ctype/tst-ctype-tls-mod.c
new file mode 100644 (file)
index 0000000..52cbb9d
--- /dev/null
+++ b/ctype/tst-ctype-tls-mod.c
@@ -0,0 +1,37 @@
+/* Wrappers for <ctype.h> macros in a secondary namespace.
+   Copyright (C) 2025 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <ctype.h>
+
+int
+my_isalpha (int ch)
+{
+  return isalpha (ch);
+}
+
+int
+my_toupper (int ch)
+{
+  return toupper (ch);
+}
+
+int
+my_tolower (int ch)
+{
+  return tolower (ch);
+}

diff --git a/ctype/tst-ctype-tls-skeleton.c b/ctype/tst-ctype-tls-skeleton.c
new file mode 100644 (file)
index 0000000..8c53e35
--- /dev/null
+++ b/ctype/tst-ctype-tls-skeleton.c
@@ -0,0 +1,67 @@
+/* Test that <ctype.h> in a secondary namespace works.
+   Copyright (C) 2025 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
+   <https://www.gnu.org/licenses/>.  */
+
+/* Before this file is included, define DO_STATIC_TEST to 0 or 1.
+   With 0, dlmopen is used for the test.  With 1, dlopen is used.  */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xdlfcn.h>
+#include <support/xthread.h>
+
+static int (*my_isalpha) (int);
+static int (*my_toupper) (int);
+static int (*my_tolower) (int);
+
+static void *
+checks (void *ignore)
+{
+  TEST_VERIFY (my_isalpha ('a'));
+  TEST_VERIFY (!my_isalpha ('0'));
+  TEST_COMPARE (my_toupper ('a'), 'A');
+  TEST_COMPARE (my_toupper ('A'), 'A');
+  TEST_COMPARE (my_tolower ('a'), 'a');
+  TEST_COMPARE (my_tolower ('A'), 'a');
+  return NULL;
+}
+
+static int
+do_test (void)
+{
+  char *dso = xasprintf ("%s/ctype/tst-ctype-tls-mod.so", support_objdir_root);
+#if DO_STATIC_TEST
+  void *handle = xdlopen (dso, RTLD_LAZY);
+#else
+  void *handle = xdlmopen (LM_ID_NEWLM, dso, RTLD_LAZY);
+#endif
+  my_isalpha = xdlsym (handle, "my_isalpha");
+  my_toupper = xdlsym (handle, "my_toupper");
+  my_tolower = xdlsym (handle, "my_tolower");
+
+  checks (NULL);
+  xpthread_join (xpthread_create (NULL, checks, NULL));
+
+  xdlclose (handle);
+  free (dso);
+
+  return 0;
+}
+
+#include <support/test-driver.c>