freebsd-skq/lib/libc/sys/interposing_table.c
Konstantin Belousov bd43f0691c If libthr.so is dlopened without RTLD_GLOBAL flag, the libthr symbols
do not participate in the global symbols namespace, but rtld locks are
still replaced and functions are interposed.  In particular,
__pthread_map_stacks_exec is resolved to the libc version.  If a
library is loaded later, which requires adjustment of the stack
protection mode, rtld calls into libc __pthread_map_stacks_exec due to
the symbols scope.  The libc version might recurse into binder and
recursively acquire rtld bind lock, causing the hang.

Make libc __pthread_map_stacks_exec() interposed, which synchronizes
rtld locks and version of the stack exec hook when libthr loaded,
regardless of the symbol scope control or symbol resolution order.

The __pthread_map_stacks_exec() symbol is removed from the private
version in libthr since libc symbol now operates correctly in presence
of libthr.

Reported and tested by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2016-02-08 19:24:13 +00:00

91 lines
3.2 KiB
C

/*
* Copyright (c) 2014 The FreeBSD Foundation.
* All rights reserved.
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice(s), this list of conditions and the following disclaimer as
* the first lines of this file unmodified other than the possible
* addition of one or more copyright notices.
* 2. Redistributions in binary form must reproduce the above copyright
* notice(s), this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include "libc_private.h"
#define SLOT(a, b) \
[INTERPOS_##a] = (interpos_func_t)b
interpos_func_t __libc_interposing[INTERPOS_MAX] = {
SLOT(accept, __sys_accept),
SLOT(accept4, __sys_accept4),
SLOT(aio_suspend, __sys_aio_suspend),
SLOT(close, __sys_close),
SLOT(connect, __sys_connect),
SLOT(fcntl, __sys_fcntl),
SLOT(fsync, __sys_fsync),
SLOT(fork, __sys_fork),
SLOT(msync, __sys_msync),
SLOT(nanosleep, __sys_nanosleep),
SLOT(openat, __sys_openat),
SLOT(poll, __sys_poll),
SLOT(pselect, __sys_pselect),
SLOT(read, __sys_read),
SLOT(readv, __sys_readv),
SLOT(recvfrom, __sys_recvfrom),
SLOT(recvmsg, __sys_recvmsg),
SLOT(select, __sys_select),
SLOT(sendmsg, __sys_sendmsg),
SLOT(sendto, __sys_sendto),
SLOT(setcontext, __sys_setcontext),
SLOT(sigaction, __sys_sigaction),
SLOT(sigprocmask, __sys_sigprocmask),
SLOT(sigsuspend, __sys_sigsuspend),
SLOT(sigwait, __libc_sigwait),
SLOT(sigtimedwait, __sys_sigtimedwait),
SLOT(sigwaitinfo, __sys_sigwaitinfo),
SLOT(swapcontext, __sys_swapcontext),
SLOT(system, __libc_system),
SLOT(tcdrain, __libc_tcdrain),
SLOT(wait4, __sys_wait4),
SLOT(write, __sys_write),
SLOT(writev, __sys_writev),
SLOT(_pthread_mutex_init_calloc_cb, _pthread_mutex_init_calloc_cb_stub),
SLOT(spinlock, __libc_spinlock_stub),
SLOT(spinunlock, __libc_spinunlock_stub),
SLOT(kevent, __sys_kevent),
SLOT(wait6, __sys_wait6),
SLOT(ppoll, __sys_ppoll),
SLOT(map_stacks_exec, __libc_map_stacks_exec),
};
#undef SLOT
interpos_func_t *
__libc_interposing_slot(int interposno)
{
return (&__libc_interposing[interposno]);
}