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* [glibc/release/2.35/master] elf: Call __libc_early_init for reused namespaces (bug 29528)
@ 2022-08-30 14:30 Florian Weimer
  0 siblings, 0 replies; only message in thread
From: Florian Weimer @ 2022-08-30 14:30 UTC (permalink / raw)
  To: glibc-cvs

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=577c2fc7f34eeaaa2ecec94108bb3f0417383a32

commit 577c2fc7f34eeaaa2ecec94108bb3f0417383a32
Author: Florian Weimer <fweimer@redhat.com>
Date:   Fri Aug 26 21:15:43 2022 +0200

    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.
    
    (cherry picked from commit d0e357ff45a75553dee3b17ed7d303bfa544f6fe)

Diff:
---
 NEWS                         |  1 +
 elf/Makefile                 | 25 ++++++++++++++++++++++
 elf/dl-open.c                | 13 +++++++-----
 elf/tst-dlmopen-twice-mod1.c | 37 ++++++++++++++++++++++++++++++++
 elf/tst-dlmopen-twice-mod2.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
 elf/tst-dlmopen-twice.c      | 34 ++++++++++++++++++++++++++++++
 6 files changed, 155 insertions(+), 5 deletions(-)

diff --git a/NEWS b/NEWS
index fd1aa89db1..1a16fc30a9 100644
--- a/NEWS
+++ b/NEWS
@@ -48,6 +48,7 @@ The following bugs are resolved with this release:
     line 184
   [29446] _dlopen now ignores dl_caller argument in static mode
   [29490] alpha: New __brk_call implementation is broken
+  [29528] elf: Call __libc_early_init for reused namespaces
 
 \f
 Version 2.35
diff --git a/elf/Makefile b/elf/Makefile
index 3536b6af5e..d29b5721bf 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -408,6 +408,7 @@ tests += \
   tst-dlmopen4 \
   tst-dlmopen-dlerror \
   tst-dlmopen-gethostbyname \
+  tst-dlmopen-twice \
   tst-dlopenfail \
   tst-dlopenfail-2 \
   tst-dlopenrpath \
@@ -795,6 +796,8 @@ 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 \
@@ -2865,3 +2868,25 @@ $(objpfx)tst-tls-allocation-failure-static-patched.out: \
 	grep -q '^Fatal glibc error: Cannot allocate TLS block$$' $@ \
 	  && grep -q '^status: 127$$' $@; \
 	  $(evaluate-test)
+
+$(objpfx)tst-audit-tlsdesc: $(objpfx)tst-audit-tlsdesc-mod1.so \
+			    $(objpfx)tst-audit-tlsdesc-mod2.so \
+			    $(shared-thread-library)
+ifeq (yes,$(have-mtls-dialect-gnu2))
+# The test is valid for all TLS types, but we want to exercise GNU2
+# TLS if possible.
+CFLAGS-tst-audit-tlsdesc-mod1.c += -mtls-dialect=gnu2
+CFLAGS-tst-audit-tlsdesc-mod2.c += -mtls-dialect=gnu2
+endif
+$(objpfx)tst-audit-tlsdesc-dlopen: $(shared-thread-library)
+$(objpfx)tst-audit-tlsdesc-dlopen.out: $(objpfx)tst-audit-tlsdesc-mod1.so \
+				       $(objpfx)tst-audit-tlsdesc-mod2.so
+$(objpfx)tst-audit-tlsdesc-mod1.so: $(objpfx)tst-audit-tlsdesc-mod2.so
+$(objpfx)tst-audit-tlsdesc.out: $(objpfx)tst-auditmod-tlsdesc.so
+tst-audit-tlsdesc-ENV = LD_AUDIT=$(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.out: \
+  $(objpfx)tst-dlmopen-twice-mod1.so \
+  $(objpfx)tst-dlmopen-twice-mod2.so
diff --git a/elf/dl-open.c b/elf/dl-open.c
index a23e65926b..46e8066fd8 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -844,11 +844,14 @@ _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid,
 	  _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_update (nsid)->r_state = RT_CONSISTENT;
     }
diff --git a/elf/tst-dlmopen-twice-mod1.c b/elf/tst-dlmopen-twice-mod1.c
new file mode 100644
index 0000000000..0eaf04948c
--- /dev/null
+++ b/elf/tst-dlmopen-twice-mod1.c
@@ -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 --git a/elf/tst-dlmopen-twice-mod2.c b/elf/tst-dlmopen-twice-mod2.c
new file mode 100644
index 0000000000..40c6c01f96
--- /dev/null
+++ b/elf/tst-dlmopen-twice-mod2.c
@@ -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 --git a/elf/tst-dlmopen-twice.c b/elf/tst-dlmopen-twice.c
new file mode 100644
index 0000000000..449f3c8fa9
--- /dev/null
+++ b/elf/tst-dlmopen-twice.c
@@ -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>

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