From d0e357ff45a75553dee3b17ed7d303bfa544f6fe Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Fri, 26 Aug 2022 21:15:43 +0200
Subject: elf: Call __libc_early_init for reused namespaces (bug 29528)
libc_map is never reset to NULL, neither during dlclose nor on a
dlopen call which reuses the namespace structure. As a result, if a
namespace is reused, its libc is not initialized properly. The most
visible result is a crash in the <ctype.h> functions.
To prevent similar bugs on namespace reuse from surfacing,
unconditionally initialize the chosen namespace to zero using memset.
[Note from DJ: Regenerated for new line numbers and context, added
link dependency on libdl]]
diff -rupN a/elf/Makefile b/elf/Makefile
--- a/elf/Makefile 2022-10-05 15:04:11.814901849 -0400
+++ b/elf/Makefile 2022-10-05 17:02:19.858635958 -0400
@@ -367,6 +367,7 @@ tests += \
tst-dlmopen3 \
tst-dlmopen-dlerror \
tst-dlmopen-gethostbyname \
+ tst-dlmopen-twice \
tst-dlopenfail \
tst-dlopenfail-2 \
tst-dlopenrpath \
@@ -671,6 +672,8 @@ modules-names = \
tst-dlmopen1mod \
tst-dlmopen-dlerror-mod \
tst-dlmopen-gethostbyname-mod \
+ tst-dlmopen-twice-mod1 \
+ tst-dlmopen-twice-mod2 \
tst-dlopenfaillinkmod \
tst-dlopenfailmod1 \
tst-dlopenfailmod2 \
@@ -2569,3 +2572,9 @@ $(objpfx)tst-audit-tlsdesc.out: $(objpfx
tst-audit-tlsdesc-ENV = LD_AUDIT=$(objpfx)tst-auditmod-tlsdesc.so
$(objpfx)tst-audit-tlsdesc-dlopen.out: $(objpfx)tst-auditmod-tlsdesc.so
tst-audit-tlsdesc-dlopen-ENV = LD_AUDIT=$(objpfx)tst-auditmod-tlsdesc.so
+
+
+$(objpfx)tst-dlmopen-twice: $(libdl)
+$(objpfx)tst-dlmopen-twice.out: \
+ $(objpfx)tst-dlmopen-twice-mod1.so \
+ $(objpfx)tst-dlmopen-twice-mod2.so
diff -rupN a/elf/dl-open.c b/elf/dl-open.c
--- a/elf/dl-open.c 2022-10-05 15:04:11.635894932 -0400
+++ b/elf/dl-open.c 2022-10-05 15:10:31.667638060 -0400
@@ -836,11 +836,14 @@ _dl_open (const char *file, int mode, co
_dl_signal_error (EINVAL, file, NULL, N_("\
no more namespaces available for dlmopen()"));
}
- else if (nsid == GL(dl_nns))
- {
- __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock);
- ++GL(dl_nns);
- }
+
+ if (nsid == GL(dl_nns))
+ ++GL(dl_nns);
+
+ /* Initialize the new namespace. Most members are
+ zero-initialized, only the lock needs special treatment. */
+ memset (&GL(dl_ns)[nsid], 0, sizeof (GL(dl_ns)[nsid]));
+ __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock);
_dl_debug_initialize (0, nsid)->r_state = RT_CONSISTENT;
}
diff -rupN a/elf/tst-dlmopen-twice-mod1.c b/elf/tst-dlmopen-twice-mod1.c
--- a/elf/tst-dlmopen-twice-mod1.c 1969-12-31 19:00:00.000000000 -0500
+++ b/elf/tst-dlmopen-twice-mod1.c 2022-10-05 15:10:31.671638216 -0400
@@ -0,0 +1,37 @@
+/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Module 1.
+ Copyright (C) 2022 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 <stdio.h>
+
+static void __attribute__ ((constructor))
+init (void)
+{
+ puts ("info: tst-dlmopen-twice-mod1.so loaded");
+ fflush (stdout);
+}
+
+static void __attribute__ ((destructor))
+fini (void)
+{
+ puts ("info: tst-dlmopen-twice-mod1.so about to be unloaded");
+ fflush (stdout);
+}
+
+/* Large allocation. The second module does not have this, so it
+ should load libc at a different address. */
+char large_allocate[16 * 1024 * 1024];
diff -rupN a/elf/tst-dlmopen-twice-mod2.c b/elf/tst-dlmopen-twice-mod2.c
--- a/elf/tst-dlmopen-twice-mod2.c 1969-12-31 19:00:00.000000000 -0500
+++ b/elf/tst-dlmopen-twice-mod2.c 2022-10-05 15:10:31.676638411 -0400
@@ -0,0 +1,50 @@
+/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Module 2.
+ Copyright (C) 2022 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>
+#include <stdio.h>
+
+static void __attribute__ ((constructor))
+init (void)
+{
+ puts ("info: tst-dlmopen-twice-mod2.so loaded");
+ fflush (stdout);
+}
+
+static void __attribute__ ((destructor))
+fini (void)
+{
+ puts ("info: tst-dlmopen-twice-mod2.so about to be unloaded");
+ fflush (stdout);
+}
+
+int
+run_check (void)
+{
+ puts ("info: about to call isalpha");
+ fflush (stdout);
+
+ volatile char ch = 'a';
+ if (!isalpha (ch))
+ {
+ puts ("error: isalpha ('a') is not true");
+ fflush (stdout);
+ return 1;
+ }
+ return 0;
+}
diff -rupN a/elf/tst-dlmopen-twice.c b/elf/tst-dlmopen-twice.c
--- a/elf/tst-dlmopen-twice.c 1969-12-31 19:00:00.000000000 -0500
+++ b/elf/tst-dlmopen-twice.c 2022-10-05 15:10:31.679638528 -0400
@@ -0,0 +1,34 @@
+/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Main.
+ Copyright (C) 2022 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 <support/xdlfcn.h>
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+ void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod1.so", RTLD_NOW);
+ xdlclose (handle);
+ handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod2.so", RTLD_NOW);
+ int (*run_check) (void) = xdlsym (handle, "run_check");
+ TEST_COMPARE (run_check (), 0);
+ xdlclose (handle);
+ return 0;
+}
+
+#include <support/test-driver.c>