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. --- elf/tst-dlmopen-twice-mod1.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 elf/tst-dlmopen-twice-mod1.c (limited to 'elf/tst-dlmopen-twice-mod1.c') diff --git a/elf/tst-dlmopen-twice-mod1.c b/elf/tst-dlmopen-twice-mod1.c new file mode 100644 index 0000000..0eaf049 --- /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 + . */ + +#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]; -- cgit v1.1