freebsd-dev/sys/compat/linux/linux_emul.c
Dmitry Chagin 23e8912c60 Implement Linux personality() system call mainly due to READ_IMPLIES_EXEC flag.
In Linux if this flag is set, PROT_READ implies PROT_EXEC for mmap().
Linux/i386 set this flag automatically if the binary requires executable stack.

READ_IMPLIES_EXEC flag will be used in the next Linux mmap() commit.
2016-07-10 08:15:50 +00:00

301 lines
7.2 KiB
C

/*-
* Copyright (c) 2006 Roman Divacky
* Copyright (c) 2013 Dmitry Chagin
* All rights reserved.
*
* 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, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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/param.h>
#include <sys/systm.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/sx.h>
#include <sys/proc.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <compat/linux/linux_emul.h>
#include <compat/linux/linux_misc.h>
#include <compat/linux/linux_persona.h>
#include <compat/linux/linux_util.h>
/*
* This returns reference to the thread emuldata entry (if found)
*
* Hold PROC_LOCK when referencing emuldata from other threads.
*/
struct linux_emuldata *
em_find(struct thread *td)
{
struct linux_emuldata *em;
em = td->td_emuldata;
return (em);
}
/*
* This returns reference to the proc pemuldata entry (if found)
*
* Hold PROC_LOCK when referencing proc pemuldata from other threads.
* Hold LINUX_PEM_LOCK wher referencing pemuldata members.
*/
struct linux_pemuldata *
pem_find(struct proc *p)
{
struct linux_pemuldata *pem;
pem = p->p_emuldata;
return (pem);
}
void
linux_proc_init(struct thread *td, struct thread *newtd, int flags)
{
struct linux_emuldata *em;
struct linux_pemuldata *pem;
struct epoll_emuldata *emd;
struct proc *p;
if (newtd != NULL) {
p = newtd->td_proc;
/* non-exec call */
em = malloc(sizeof(*em), M_TEMP, M_WAITOK | M_ZERO);
if (flags & LINUX_CLONE_THREAD) {
LINUX_CTR1(proc_init, "thread newtd(%d)",
newtd->td_tid);
em->em_tid = newtd->td_tid;
} else {
LINUX_CTR1(proc_init, "fork newtd(%d)", p->p_pid);
em->em_tid = p->p_pid;
pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO);
sx_init(&pem->pem_sx, "lpemlk");
p->p_emuldata = pem;
}
newtd->td_emuldata = em;
} else {
p = td->td_proc;
/* exec */
LINUX_CTR1(proc_init, "exec newtd(%d)", p->p_pid);
/* lookup the old one */
em = em_find(td);
KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
em->em_tid = p->p_pid;
em->flags = 0;
em->pdeath_signal = 0;
em->robust_futexes = NULL;
em->child_clear_tid = NULL;
em->child_set_tid = NULL;
/* epoll should be destroyed in a case of exec. */
pem = pem_find(p);
KASSERT(pem != NULL, ("proc_exit: proc emuldata not found.\n"));
pem->persona = 0;
if (pem->epoll != NULL) {
emd = pem->epoll;
pem->epoll = NULL;
free(emd, M_EPOLL);
}
}
}
void
linux_proc_exit(void *arg __unused, struct proc *p)
{
struct linux_pemuldata *pem;
struct epoll_emuldata *emd;
struct thread *td = curthread;
if (__predict_false(SV_CURPROC_ABI() != SV_ABI_LINUX))
return;
LINUX_CTR3(proc_exit, "thread(%d) proc(%d) p %p",
td->td_tid, p->p_pid, p);
pem = pem_find(p);
if (pem == NULL)
return;
(p->p_sysent->sv_thread_detach)(td);
p->p_emuldata = NULL;
if (pem->epoll != NULL) {
emd = pem->epoll;
pem->epoll = NULL;
free(emd, M_EPOLL);
}
sx_destroy(&pem->pem_sx);
free(pem, M_LINUX);
}
int
linux_common_execve(struct thread *td, struct image_args *eargs)
{
struct linux_pemuldata *pem;
struct epoll_emuldata *emd;
struct vmspace *oldvmspace;
struct linux_emuldata *em;
struct proc *p;
int error;
p = td->td_proc;
error = pre_execve(td, &oldvmspace);
if (error != 0)
return (error);
error = kern_execve(td, eargs, NULL);
post_execve(td, error, oldvmspace);
if (error != 0)
return (error);
/*
* In a case of transition from Linux binary execing to
* FreeBSD binary we destroy linux emuldata thread & proc entries.
*/
if (SV_CURPROC_ABI() != SV_ABI_LINUX) {
PROC_LOCK(p);
em = em_find(td);
KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n"));
td->td_emuldata = NULL;
pem = pem_find(p);
KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n"));
p->p_emuldata = NULL;
PROC_UNLOCK(p);
if (pem->epoll != NULL) {
emd = pem->epoll;
pem->epoll = NULL;
free(emd, M_EPOLL);
}
free(em, M_TEMP);
free(pem, M_LINUX);
}
return (0);
}
void
linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
{
struct thread *td = curthread;
struct thread *othertd;
#if defined(__amd64__)
struct linux_pemuldata *pem;
#endif
/*
* In a case of execing from linux binary properly detach
* other threads from the user space.
*/
if (__predict_false(SV_PROC_ABI(p) == SV_ABI_LINUX)) {
FOREACH_THREAD_IN_PROC(p, othertd) {
if (td != othertd)
(p->p_sysent->sv_thread_detach)(othertd);
}
}
/*
* In a case of execing to linux binary we create linux
* emuldata thread entry.
*/
if (__predict_false((imgp->sysent->sv_flags & SV_ABI_MASK) ==
SV_ABI_LINUX)) {
if (SV_PROC_ABI(p) == SV_ABI_LINUX)
linux_proc_init(td, NULL, 0);
else
linux_proc_init(td, td, 0);
#if defined(__amd64__)
/*
* An IA32 executable which has executable stack will have the
* READ_IMPLIES_EXEC personality flag set automatically.
*/
if (SV_PROC_FLAG(td->td_proc, SV_ILP32) &&
imgp->stack_prot & VM_PROT_EXECUTE) {
pem = pem_find(p);
pem->persona |= LINUX_READ_IMPLIES_EXEC;
}
#endif
}
}
void
linux_thread_dtor(void *arg __unused, struct thread *td)
{
struct linux_emuldata *em;
em = em_find(td);
if (em == NULL)
return;
td->td_emuldata = NULL;
LINUX_CTR1(thread_dtor, "thread(%d)", em->em_tid);
free(em, M_TEMP);
}
void
linux_schedtail(struct thread *td)
{
struct linux_emuldata *em;
struct proc *p;
int error = 0;
int *child_set_tid;
p = td->td_proc;
em = em_find(td);
KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n"));
child_set_tid = em->child_set_tid;
if (child_set_tid != NULL) {
error = copyout(&em->em_tid, child_set_tid,
sizeof(em->em_tid));
LINUX_CTR4(schedtail, "thread(%d) %p stored %d error %d",
td->td_tid, child_set_tid, em->em_tid, error);
} else
LINUX_CTR1(schedtail, "thread(%d)", em->em_tid);
}