From d0e357ff45a75553dee3b17ed7d303bfa544f6fe Mon Sep 17 00:00:00 2001 From: Florian Weimer 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 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 + . */ + +#include + +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 + . */ + +#include +#include + +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 + . */ + +#include +#include + +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