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NetBSD/sys/kern/kern_exec.c

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/* $NetBSD: kern_exec.c,v 1.501 2020/05/23 23:42:43 ad Exp $ */
/*-
* Copyright (c) 2008, 2019, 2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Andrew Doran.
*
* 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.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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.
*/
/*-
* Copyright (C) 1993, 1994, 1996 Christopher G. Demetriou
* Copyright (C) 1992 Wolfgang Solfrank.
* Copyright (C) 1992 TooLs GmbH.
* 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.
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by TooLs GmbH.
* 4. The name of TooLs GmbH may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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>
__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.501 2020/05/23 23:42:43 ad Exp $");
#include "opt_exec.h"
#include "opt_execfmt.h"
#include "opt_ktrace.h"
#include "opt_modular.h"
#include "opt_syscall_debug.h"
#include "veriexec.h"
#include "opt_pax.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/ptrace.h>
#include <sys/mount.h>
#include <sys/kmem.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/acct.h>
#include <sys/atomic.h>
#include <sys/exec.h>
#include <sys/ktrace.h>
#include <sys/uidinfo.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <sys/ras.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/kauth.h>
#include <sys/lwpctl.h>
#include <sys/pax.h>
#include <sys/cpu.h>
#include <sys/module.h>
#include <sys/syscallvar.h>
#include <sys/syscallargs.h>
#if NVERIEXEC > 0
#include <sys/verified_exec.h>
#endif /* NVERIEXEC > 0 */
#include <sys/sdt.h>
#include <sys/spawn.h>
#include <sys/prot.h>
#include <sys/cprng.h>
#include <uvm/uvm_extern.h>
#include <machine/reg.h>
#include <compat/common/compat_util.h>
#ifndef MD_TOPDOWN_INIT
#ifdef __USE_TOPDOWN_VM
#define MD_TOPDOWN_INIT(epp) (epp)->ep_flags |= EXEC_TOPDOWN_VM
#else
#define MD_TOPDOWN_INIT(epp)
#endif
#endif
struct execve_data;
extern int user_va0_disable;
static size_t calcargs(struct execve_data * restrict, const size_t);
static size_t calcstack(struct execve_data * restrict, const size_t);
static int copyoutargs(struct execve_data * restrict, struct lwp *,
char * const);
static int copyoutpsstrs(struct execve_data * restrict, struct proc *);
static int copyinargs(struct execve_data * restrict, char * const *,
char * const *, execve_fetch_element_t, char **);
static int copyinargstrs(struct execve_data * restrict, char * const *,
execve_fetch_element_t, char **, size_t *, void (*)(const void *, size_t));
static int exec_sigcode_map(struct proc *, const struct emul *);
#if defined(DEBUG) && !defined(DEBUG_EXEC)
#define DEBUG_EXEC
#endif
#ifdef DEBUG_EXEC
#define DPRINTF(a) printf a
#define COPYPRINTF(s, a, b) printf("%s, %d: copyout%s @%p %zu\n", __func__, \
__LINE__, (s), (a), (b))
static void dump_vmcmds(const struct exec_package * const, size_t, int);
#define DUMPVMCMDS(p, x, e) do { dump_vmcmds((p), (x), (e)); } while (0)
#else
#define DPRINTF(a)
#define COPYPRINTF(s, a, b)
#define DUMPVMCMDS(p, x, e) do {} while (0)
#endif /* DEBUG_EXEC */
/*
* DTrace SDT provider definitions
*/
SDT_PROVIDER_DECLARE(proc);
SDT_PROBE_DEFINE1(proc, kernel, , exec, "char *");
SDT_PROBE_DEFINE1(proc, kernel, , exec__success, "char *");
SDT_PROBE_DEFINE1(proc, kernel, , exec__failure, "int");
/*
* Exec function switch:
*
* Note that each makecmds function is responsible for loading the
* exec package with the necessary functions for any exec-type-specific
* handling.
*
* Functions for specific exec types should be defined in their own
* header file.
*/
static const struct execsw **execsw = NULL;
static int nexecs;
u_int exec_maxhdrsz; /* must not be static - used by netbsd32 */
/* list of dynamically loaded execsw entries */
static LIST_HEAD(execlist_head, exec_entry) ex_head =
LIST_HEAD_INITIALIZER(ex_head);
struct exec_entry {
LIST_ENTRY(exec_entry) ex_list;
SLIST_ENTRY(exec_entry) ex_slist;
const struct execsw *ex_sw;
};
#ifndef __HAVE_SYSCALL_INTERN
void syscall(void);
#endif
/* NetBSD autoloadable syscalls */
#ifdef MODULAR
#include <kern/syscalls_autoload.c>
#endif
/* NetBSD emul struct */
struct emul emul_netbsd = {
.e_name = "netbsd",
#ifdef EMUL_NATIVEROOT
.e_path = EMUL_NATIVEROOT,
#else
.e_path = NULL,
#endif
#ifndef __HAVE_MINIMAL_EMUL
.e_flags = EMUL_HAS_SYS___syscall,
.e_errno = NULL,
.e_nosys = SYS_syscall,
.e_nsysent = SYS_NSYSENT,
#endif
#ifdef MODULAR
.e_sc_autoload = netbsd_syscalls_autoload,
#endif
.e_sysent = sysent,
.e_nomodbits = sysent_nomodbits,
#ifdef SYSCALL_DEBUG
.e_syscallnames = syscallnames,
#else
.e_syscallnames = NULL,
#endif
.e_sendsig = sendsig,
.e_trapsignal = trapsignal,
.e_sigcode = NULL,
.e_esigcode = NULL,
.e_sigobject = NULL,
.e_setregs = setregs,
.e_proc_exec = NULL,
.e_proc_fork = NULL,
.e_proc_exit = NULL,
.e_lwp_fork = NULL,
.e_lwp_exit = NULL,
#ifdef __HAVE_SYSCALL_INTERN
.e_syscall_intern = syscall_intern,
#else
.e_syscall = syscall,
#endif
.e_sysctlovly = NULL,
.e_vm_default_addr = uvm_default_mapaddr,
.e_usertrap = NULL,
.e_ucsize = sizeof(ucontext_t),
.e_startlwp = startlwp
};
/*
* Exec lock. Used to control access to execsw[] structures.
* This must not be static so that netbsd32 can access it, too.
*/
krwlock_t exec_lock __cacheline_aligned;
static kmutex_t sigobject_lock __cacheline_aligned;
/*
* Data used between a loadvm and execve part of an "exec" operation
*/
struct execve_data {
struct exec_package ed_pack;
struct pathbuf *ed_pathbuf;
struct vattr ed_attr;
struct ps_strings ed_arginfo;
char *ed_argp;
const char *ed_pathstring;
char *ed_resolvedname;
size_t ed_ps_strings_sz;
int ed_szsigcode;
size_t ed_argslen;
long ed_argc;
long ed_envc;
};
/*
* data passed from parent lwp to child during a posix_spawn()
*/
struct spawn_exec_data {
struct execve_data sed_exec;
struct posix_spawn_file_actions
*sed_actions;
struct posix_spawnattr *sed_attrs;
struct proc *sed_parent;
kcondvar_t sed_cv_child_ready;
kmutex_t sed_mtx_child;
int sed_error;
volatile uint32_t sed_refcnt;
};
static struct vm_map *exec_map;
static struct pool exec_pool;
static void *
exec_pool_alloc(struct pool *pp, int flags)
{
return (void *)uvm_km_alloc(exec_map, NCARGS, 0,
UVM_KMF_PAGEABLE | UVM_KMF_WAITVA);
}
static void
exec_pool_free(struct pool *pp, void *addr)
{
uvm_km_free(exec_map, (vaddr_t)addr, NCARGS, UVM_KMF_PAGEABLE);
}
static struct pool_allocator exec_palloc = {
.pa_alloc = exec_pool_alloc,
.pa_free = exec_pool_free,
.pa_pagesz = NCARGS
};
static void
exec_path_free(struct execve_data *data)
{
pathbuf_stringcopy_put(data->ed_pathbuf, data->ed_pathstring);
pathbuf_destroy(data->ed_pathbuf);
if (data->ed_resolvedname)
PNBUF_PUT(data->ed_resolvedname);
}
static int
exec_resolvename(struct lwp *l, struct exec_package *epp, struct vnode *vp,
char **rpath)
{
int error;
char *p;
KASSERT(rpath != NULL);
*rpath = PNBUF_GET();
error = vnode_to_path(*rpath, MAXPATHLEN, vp, l, l->l_proc);
if (error) {
DPRINTF(("%s: can't resolve name for %s, error %d\n",
__func__, epp->ep_kname, error));
PNBUF_PUT(*rpath);
*rpath = NULL;
return error;
}
epp->ep_resolvedname = *rpath;
if ((p = strrchr(*rpath, '/')) != NULL)
epp->ep_kname = p + 1;
return 0;
}
/*
* check exec:
* given an "executable" described in the exec package's namei info,
* see what we can do with it.
*
* ON ENTRY:
* exec package with appropriate namei info
* lwp pointer of exec'ing lwp
* NO SELF-LOCKED VNODES
*
* ON EXIT:
* error: nothing held, etc. exec header still allocated.
* ok: filled exec package, executable's vnode (unlocked).
*
* EXEC SWITCH ENTRY:
* Locked vnode to check, exec package, proc.
*
* EXEC SWITCH EXIT:
* ok: return 0, filled exec package, executable's vnode (unlocked).
* error: destructive:
* everything deallocated execept exec header.
* non-destructive:
* error code, executable's vnode (unlocked),
* exec header unmodified.
*/
int
/*ARGSUSED*/
check_exec(struct lwp *l, struct exec_package *epp, struct pathbuf *pb,
char **rpath)
{
int error, i;
struct vnode *vp;
size_t resid;
if (epp->ep_resolvedname) {
struct nameidata nd;
// grab the absolute pathbuf here before namei() trashes it.
pathbuf_copystring(pb, epp->ep_resolvedname, PATH_MAX);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb);
/* first get the vnode */
if ((error = namei(&nd)) != 0)
return error;
epp->ep_vp = vp = nd.ni_vp;
#ifdef DIAGNOSTIC
/* paranoia (take this out once namei stuff stabilizes) */
memset(nd.ni_pnbuf, '~', PATH_MAX);
#endif
} else {
struct file *fp;
if ((error = fd_getvnode(epp->ep_xfd, &fp)) != 0)
return error;
epp->ep_vp = vp = fp->f_vnode;
vref(vp);
fd_putfile(epp->ep_xfd);
if ((error = exec_resolvename(l, epp, vp, rpath)) != 0)
return error;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
}
/* check access and type */
if (vp->v_type != VREG) {
error = EACCES;
goto bad1;
}
if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0)
goto bad1;
/* get attributes */
/* XXX VOP_GETATTR is the only thing that needs LK_EXCLUSIVE here */
if ((error = VOP_GETATTR(vp, epp->ep_vap, l->l_cred)) != 0)
goto bad1;
/* Check mount point */
if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
error = EACCES;
goto bad1;
}
if (vp->v_mount->mnt_flag & MNT_NOSUID)
epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
/* try to open it */
if ((error = VOP_OPEN(vp, FREAD, l->l_cred)) != 0)
goto bad1;
/* now we have the file, get the exec header */
error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0,
UIO_SYSSPACE, IO_NODELOCKED, l->l_cred, &resid, NULL);
if (error)
goto bad1;
/* unlock vp, since we need it unlocked from here on out. */
VOP_UNLOCK(vp);
#if NVERIEXEC > 0
error = veriexec_verify(l, vp,
epp->ep_resolvedname ? epp->ep_resolvedname : epp->ep_kname,
epp->ep_flags & EXEC_INDIR ? VERIEXEC_INDIRECT : VERIEXEC_DIRECT,
NULL);
if (error)
goto bad2;
#endif /* NVERIEXEC > 0 */
#ifdef PAX_SEGVGUARD
error = pax_segvguard(l, vp, epp->ep_resolvedname, false);
if (error)
goto bad2;
#endif /* PAX_SEGVGUARD */
epp->ep_hdrvalid = epp->ep_hdrlen - resid;
/*
* Set up default address space limits. Can be overridden
* by individual exec packages.
*/
epp->ep_vm_minaddr = exec_vm_minaddr(VM_MIN_ADDRESS);
epp->ep_vm_maxaddr = VM_MAXUSER_ADDRESS;
/*
* set up the vmcmds for creation of the process
* address space
*/
error = ENOEXEC;
for (i = 0; i < nexecs; i++) {
int newerror;
epp->ep_esch = execsw[i];
newerror = (*execsw[i]->es_makecmds)(l, epp);
if (!newerror) {
/* Seems ok: check that entry point is not too high */
if (epp->ep_entry >= epp->ep_vm_maxaddr) {
#ifdef DIAGNOSTIC
printf("%s: rejecting %p due to "
"too high entry address (>= %p)\n",
__func__, (void *)epp->ep_entry,
(void *)epp->ep_vm_maxaddr);
#endif
error = ENOEXEC;
break;
}
/* Seems ok: check that entry point is not too low */
if (epp->ep_entry < epp->ep_vm_minaddr) {
#ifdef DIAGNOSTIC
printf("%s: rejecting %p due to "
"too low entry address (< %p)\n",
__func__, (void *)epp->ep_entry,
(void *)epp->ep_vm_minaddr);
#endif
error = ENOEXEC;
break;
}
/* check limits */
if ((epp->ep_tsize > MAXTSIZ) ||
(epp->ep_dsize > (u_quad_t)l->l_proc->p_rlimit
[RLIMIT_DATA].rlim_cur)) {
#ifdef DIAGNOSTIC
printf("%s: rejecting due to "
"limits (t=%llu > %llu || d=%llu > %llu)\n",
__func__,
(unsigned long long)epp->ep_tsize,
(unsigned long long)MAXTSIZ,
(unsigned long long)epp->ep_dsize,
(unsigned long long)
l->l_proc->p_rlimit[RLIMIT_DATA].rlim_cur);
#endif
error = ENOMEM;
break;
}
return 0;
}
/*
* Reset all the fields that may have been modified by the
* loader.
*/
KASSERT(epp->ep_emul_arg == NULL);
if (epp->ep_emul_root != NULL) {
vrele(epp->ep_emul_root);
epp->ep_emul_root = NULL;
}
if (epp->ep_interp != NULL) {
vrele(epp->ep_interp);
epp->ep_interp = NULL;
}
epp->ep_pax_flags = 0;
/* make sure the first "interesting" error code is saved. */
if (error == ENOEXEC)
error = newerror;
if (epp->ep_flags & EXEC_DESTR)
/* Error from "#!" code, tidied up by recursive call */
return error;
}
/* not found, error */
/*
* free any vmspace-creation commands,
* and release their references
*/
kill_vmcmds(&epp->ep_vmcmds);
#if NVERIEXEC > 0 || defined(PAX_SEGVGUARD)
bad2:
#endif
/*
* close and release the vnode, restore the old one, free the
* pathname buf, and punt.
*/
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
VOP_CLOSE(vp, FREAD, l->l_cred);
vput(vp);
return error;
bad1:
/*
* free the namei pathname buffer, and put the vnode
* (which we don't yet have open).
*/
vput(vp); /* was still locked */
return error;
}
#ifdef __MACHINE_STACK_GROWS_UP
#define STACK_PTHREADSPACE NBPG
#else
#define STACK_PTHREADSPACE 0
#endif
static int
execve_fetch_element(char * const *array, size_t index, char **value)
{
return copyin(array + index, value, sizeof(*value));
}
/*
* exec system call
*/
int
sys_execve(struct lwp *l, const struct sys_execve_args *uap, register_t *retval)
{
/* {
syscallarg(const char *) path;
syscallarg(char * const *) argp;
syscallarg(char * const *) envp;
} */
return execve1(l, true, SCARG(uap, path), -1, SCARG(uap, argp),
SCARG(uap, envp), execve_fetch_element);
}
int
sys_fexecve(struct lwp *l, const struct sys_fexecve_args *uap,
register_t *retval)
{
/* {
syscallarg(int) fd;
syscallarg(char * const *) argp;
syscallarg(char * const *) envp;
} */
return execve1(l, false, NULL, SCARG(uap, fd), SCARG(uap, argp),
SCARG(uap, envp), execve_fetch_element);
}
/*
* Load modules to try and execute an image that we do not understand.
* If no execsw entries are present, we load those likely to be needed
* in order to run native images only. Otherwise, we autoload all
* possible modules that could let us run the binary. XXX lame
*/
static void
exec_autoload(void)
{
#ifdef MODULAR
static const char * const native[] = {
"exec_elf32",
"exec_elf64",
"exec_script",
NULL
};
static const char * const compat[] = {
"exec_elf32",
"exec_elf64",
"exec_script",
"exec_aout",
"exec_coff",
"exec_ecoff",
"compat_aoutm68k",
"compat_netbsd32",
#if 0
"compat_linux",
"compat_linux32",
#endif
"compat_sunos",
"compat_sunos32",
"compat_ultrix",
NULL
};
char const * const *list;
int i;
list = nexecs == 0 ? native : compat;
for (i = 0; list[i] != NULL; i++) {
if (module_autoload(list[i], MODULE_CLASS_EXEC) != 0) {
continue;
}
yield();
}
#endif
}
/*
* Copy the user or kernel supplied upath to the allocated pathbuffer pbp
* making it absolute in the process, by prepending the current working
* directory if it is not. If offs is supplied it will contain the offset
* where the original supplied copy of upath starts.
*/
int
exec_makepathbuf(struct lwp *l, const char *upath, enum uio_seg seg,
struct pathbuf **pbp, size_t *offs)
{
char *path, *bp;
size_t len, tlen;
int error;
struct cwdinfo *cwdi;
path = PNBUF_GET();
if (seg == UIO_SYSSPACE) {
error = copystr(upath, path, MAXPATHLEN, &len);
} else {
error = copyinstr(upath, path, MAXPATHLEN, &len);
}
if (error)
goto err;
if (path[0] == '/') {
if (offs)
*offs = 0;
goto out;
}
len++;
if (len + 1 >= MAXPATHLEN) {
error = ENAMETOOLONG;
goto err;
}
bp = path + MAXPATHLEN - len;
memmove(bp, path, len);
*(--bp) = '/';
cwdi = l->l_proc->p_cwdi;
rw_enter(&cwdi->cwdi_lock, RW_READER);
error = getcwd_common(cwdi->cwdi_cdir, NULL, &bp, path, MAXPATHLEN / 2,
GETCWD_CHECK_ACCESS, l);
rw_exit(&cwdi->cwdi_lock);
if (error)
goto err;
tlen = path + MAXPATHLEN - bp;
memmove(path, bp, tlen);
path[tlen - 1] = '\0';
if (offs)
*offs = tlen - len;
out:
*pbp = pathbuf_assimilate(path);
return 0;
err:
PNBUF_PUT(path);
return error;
}
vaddr_t
exec_vm_minaddr(vaddr_t va_min)
{
/*
* Increase va_min if we don't want NULL to be mappable by the
* process.
*/
#define VM_MIN_GUARD PAGE_SIZE
if (user_va0_disable && (va_min < VM_MIN_GUARD))
return VM_MIN_GUARD;
return va_min;
}
static int
execve_loadvm(struct lwp *l, bool has_path, const char *path, int fd,
char * const *args, char * const *envs,
execve_fetch_element_t fetch_element,
struct execve_data * restrict data)
{
struct exec_package * const epp = &data->ed_pack;
int error;
struct proc *p;
char *dp;
u_int modgen;
KASSERT(data != NULL);
p = l->l_proc;
modgen = 0;
SDT_PROBE(proc, kernel, , exec, path, 0, 0, 0, 0);
/*
* Check if we have exceeded our number of processes limit.
* This is so that we handle the case where a root daemon
* forked, ran setuid to become the desired user and is trying
* to exec. The obvious place to do the reference counting check
* is setuid(), but we don't do the reference counting check there
* like other OS's do because then all the programs that use setuid()
* must be modified to check the return code of setuid() and exit().
* It is dangerous to make setuid() fail, because it fails open and
* the program will continue to run as root. If we make it succeed
* and return an error code, again we are not enforcing the limit.
* The best place to enforce the limit is here, when the process tries
* to execute a new image, because eventually the process will need
* to call exec in order to do something useful.
*/
retry:
if (p->p_flag & PK_SUGID) {
if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_RLIMIT,
p, KAUTH_ARG(KAUTH_REQ_PROCESS_RLIMIT_BYPASS),
&p->p_rlimit[RLIMIT_NPROC],
KAUTH_ARG(RLIMIT_NPROC)) != 0 &&
chgproccnt(kauth_cred_getuid(l->l_cred), 0) >
p->p_rlimit[RLIMIT_NPROC].rlim_cur)
return EAGAIN;
}
/*
* Drain existing references and forbid new ones. The process
* should be left alone until we're done here. This is necessary
* to avoid race conditions - e.g. in ptrace() - that might allow
* a local user to illicitly obtain elevated privileges.
*/
rw_enter(&p->p_reflock, RW_WRITER);
if (has_path) {
size_t offs;
/*
* Init the namei data to point the file user's program name.
* This is done here rather than in check_exec(), so that it's
* possible to override this settings if any of makecmd/probe
* functions call check_exec() recursively - for example,
* see exec_script_makecmds().
*/
if ((error = exec_makepathbuf(l, path, UIO_USERSPACE,
&data->ed_pathbuf, &offs)) != 0)
goto clrflg;
data->ed_pathstring = pathbuf_stringcopy_get(data->ed_pathbuf);
epp->ep_kname = data->ed_pathstring + offs;
data->ed_resolvedname = PNBUF_GET();
epp->ep_resolvedname = data->ed_resolvedname;
epp->ep_xfd = -1;
} else {
data->ed_pathbuf = pathbuf_assimilate(strcpy(PNBUF_GET(), "/"));
data->ed_pathstring = pathbuf_stringcopy_get(data->ed_pathbuf);
epp->ep_kname = "*fexecve*";
data->ed_resolvedname = NULL;
epp->ep_resolvedname = NULL;
epp->ep_xfd = fd;
}
/*
* initialize the fields of the exec package.
*/
epp->ep_hdr = kmem_alloc(exec_maxhdrsz, KM_SLEEP);
epp->ep_hdrlen = exec_maxhdrsz;
epp->ep_hdrvalid = 0;
epp->ep_emul_arg = NULL;
epp->ep_emul_arg_free = NULL;
memset(&epp->ep_vmcmds, 0, sizeof(epp->ep_vmcmds));
epp->ep_vap = &data->ed_attr;
epp->ep_flags = (p->p_flag & PK_32) ? EXEC_FROM32 : 0;
MD_TOPDOWN_INIT(epp);
epp->ep_emul_root = NULL;
epp->ep_interp = NULL;
epp->ep_esch = NULL;
epp->ep_pax_flags = 0;
memset(epp->ep_machine_arch, 0, sizeof(epp->ep_machine_arch));
rw_enter(&exec_lock, RW_READER);
/* see if we can run it. */
if ((error = check_exec(l, epp, data->ed_pathbuf,
&data->ed_resolvedname)) != 0) {
if (error != ENOENT && error != EACCES && error != ENOEXEC) {
DPRINTF(("%s: check exec failed for %s, error %d\n",
__func__, epp->ep_kname, error));
}
goto freehdr;
}
/* allocate an argument buffer */
data->ed_argp = pool_get(&exec_pool, PR_WAITOK);
KASSERT(data->ed_argp != NULL);
dp = data->ed_argp;
if ((error = copyinargs(data, args, envs, fetch_element, &dp)) != 0) {
goto bad;
}
/*
* Calculate the new stack size.
*/
#ifdef __MACHINE_STACK_GROWS_UP
/*
* copyargs() fills argc/argv/envp from the lower address even on
* __MACHINE_STACK_GROWS_UP machines. Reserve a few words just below the SP
* so that _rtld() use it.
*/
#define RTLD_GAP 32
#else
#define RTLD_GAP 0
#endif
const size_t argenvstrlen = (char *)ALIGN(dp) - data->ed_argp;
data->ed_argslen = calcargs(data, argenvstrlen);
const size_t len = calcstack(data, pax_aslr_stack_gap(epp) + RTLD_GAP);
if (len > epp->ep_ssize) {
/* in effect, compare to initial limit */
DPRINTF(("%s: stack limit exceeded %zu\n", __func__, len));
error = ENOMEM;
goto bad;
}
/* adjust "active stack depth" for process VSZ */
epp->ep_ssize = len;
return 0;
bad:
/* free the vmspace-creation commands, and release their references */
kill_vmcmds(&epp->ep_vmcmds);
/* kill any opened file descriptor, if necessary */
if (epp->ep_flags & EXEC_HASFD) {
epp->ep_flags &= ~EXEC_HASFD;
fd_close(epp->ep_fd);
}
/* close and put the exec'd file */
vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY);
VOP_CLOSE(epp->ep_vp, FREAD, l->l_cred);
vput(epp->ep_vp);
pool_put(&exec_pool, data->ed_argp);
freehdr:
kmem_free(epp->ep_hdr, epp->ep_hdrlen);
if (epp->ep_emul_root != NULL)
vrele(epp->ep_emul_root);
if (epp->ep_interp != NULL)
vrele(epp->ep_interp);
rw_exit(&exec_lock);
exec_path_free(data);
clrflg:
rw_exit(&p->p_reflock);
if (modgen != module_gen && error == ENOEXEC) {
modgen = module_gen;
exec_autoload();
goto retry;
}
SDT_PROBE(proc, kernel, , exec__failure, error, 0, 0, 0, 0);
return error;
}
static int
execve_dovmcmds(struct lwp *l, struct execve_data * restrict data)
{
struct exec_package * const epp = &data->ed_pack;
struct proc *p = l->l_proc;
struct exec_vmcmd *base_vcp;
int error = 0;
size_t i;
/* record proc's vnode, for use by procfs and others */
if (p->p_textvp)
vrele(p->p_textvp);
vref(epp->ep_vp);
p->p_textvp = epp->ep_vp;
/* create the new process's VM space by running the vmcmds */
KASSERTMSG(epp->ep_vmcmds.evs_used != 0, "%s: no vmcmds", __func__);
#ifdef TRACE_EXEC
DUMPVMCMDS(epp, 0, 0);
#endif
base_vcp = NULL;
for (i = 0; i < epp->ep_vmcmds.evs_used && !error; i++) {
struct exec_vmcmd *vcp;
vcp = &epp->ep_vmcmds.evs_cmds[i];
if (vcp->ev_flags & VMCMD_RELATIVE) {
KASSERTMSG(base_vcp != NULL,
"%s: relative vmcmd with no base", __func__);
KASSERTMSG((vcp->ev_flags & VMCMD_BASE) == 0,
"%s: illegal base & relative vmcmd", __func__);
vcp->ev_addr += base_vcp->ev_addr;
}
error = (*vcp->ev_proc)(l, vcp);
if (error)
DUMPVMCMDS(epp, i, error);
if (vcp->ev_flags & VMCMD_BASE)
base_vcp = vcp;
}
/* free the vmspace-creation commands, and release their references */
kill_vmcmds(&epp->ep_vmcmds);
vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY);
VOP_CLOSE(epp->ep_vp, FREAD, l->l_cred);
vput(epp->ep_vp);
/* if an error happened, deallocate and punt */
if (error != 0) {
DPRINTF(("%s: vmcmd %zu failed: %d\n", __func__, i - 1, error));
}
return error;
}
static void
execve_free_data(struct execve_data *data)
{
struct exec_package * const epp = &data->ed_pack;
/* free the vmspace-creation commands, and release their references */
kill_vmcmds(&epp->ep_vmcmds);
/* kill any opened file descriptor, if necessary */
if (epp->ep_flags & EXEC_HASFD) {
epp->ep_flags &= ~EXEC_HASFD;
fd_close(epp->ep_fd);
}
/* close and put the exec'd file */
vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY);
VOP_CLOSE(epp->ep_vp, FREAD, curlwp->l_cred);
vput(epp->ep_vp);
pool_put(&exec_pool, data->ed_argp);
kmem_free(epp->ep_hdr, epp->ep_hdrlen);
if (epp->ep_emul_root != NULL)
vrele(epp->ep_emul_root);
if (epp->ep_interp != NULL)
vrele(epp->ep_interp);
exec_path_free(data);
}
static void
pathexec(struct proc *p, const char *resolvedname)
{
/* set command name & other accounting info */
const char *cmdname;
if (resolvedname == NULL) {
cmdname = "*fexecve*";
resolvedname = "/";
} else {
cmdname = strrchr(resolvedname, '/') + 1;
}
KASSERTMSG(resolvedname[0] == '/', "bad resolvedname `%s'",
resolvedname);
strlcpy(p->p_comm, cmdname, sizeof(p->p_comm));
kmem_strfree(p->p_path);
p->p_path = kmem_strdupsize(resolvedname, NULL, KM_SLEEP);
}
/* XXX elsewhere */
static int
credexec(struct lwp *l, struct vattr *attr)
{
struct proc *p = l->l_proc;
int error;
/*
* Deal with set[ug]id. MNT_NOSUID has already been used to disable
* s[ug]id. It's OK to check for PSL_TRACED here as we have blocked
* out additional references on the process for the moment.
*/
if ((p->p_slflag & PSL_TRACED) == 0 &&
(((attr->va_mode & S_ISUID) != 0 &&
kauth_cred_geteuid(l->l_cred) != attr->va_uid) ||
((attr->va_mode & S_ISGID) != 0 &&
kauth_cred_getegid(l->l_cred) != attr->va_gid))) {
/*
* Mark the process as SUGID before we do
* anything that might block.
*/
proc_crmod_enter();
proc_crmod_leave(NULL, NULL, true);
/* Make sure file descriptors 0..2 are in use. */
if ((error = fd_checkstd()) != 0) {
DPRINTF(("%s: fdcheckstd failed %d\n",
__func__, error));
return error;
}
/*
* Copy the credential so other references don't see our
* changes.
*/
l->l_cred = kauth_cred_copy(l->l_cred);
#ifdef KTRACE
/*
* If the persistent trace flag isn't set, turn off.
*/
if (p->p_tracep) {
mutex_enter(&ktrace_lock);
if (!(p->p_traceflag & KTRFAC_PERSISTENT))
ktrderef(p);
mutex_exit(&ktrace_lock);
}
#endif
if (attr->va_mode & S_ISUID)
kauth_cred_seteuid(l->l_cred, attr->va_uid);
if (attr->va_mode & S_ISGID)
kauth_cred_setegid(l->l_cred, attr->va_gid);
} else {
if (kauth_cred_geteuid(l->l_cred) ==
kauth_cred_getuid(l->l_cred) &&
kauth_cred_getegid(l->l_cred) ==
kauth_cred_getgid(l->l_cred))
p->p_flag &= ~PK_SUGID;
}
/*
* Copy the credential so other references don't see our changes.
* Test to see if this is necessary first, since in the common case
* we won't need a private reference.
*/
if (kauth_cred_geteuid(l->l_cred) != kauth_cred_getsvuid(l->l_cred) ||
kauth_cred_getegid(l->l_cred) != kauth_cred_getsvgid(l->l_cred)) {
l->l_cred = kauth_cred_copy(l->l_cred);
kauth_cred_setsvuid(l->l_cred, kauth_cred_geteuid(l->l_cred));
kauth_cred_setsvgid(l->l_cred, kauth_cred_getegid(l->l_cred));
}
/* Update the master credentials. */
if (l->l_cred != p->p_cred) {
kauth_cred_t ocred;
kauth_cred_hold(l->l_cred);
mutex_enter(p->p_lock);
ocred = p->p_cred;
p->p_cred = l->l_cred;
mutex_exit(p->p_lock);
kauth_cred_free(ocred);
}
return 0;
}
static void
emulexec(struct lwp *l, struct exec_package *epp)
{
struct proc *p = l->l_proc;
/* The emulation root will usually have been found when we looked
* for the elf interpreter (or similar), if not look now. */
if (epp->ep_esch->es_emul->e_path != NULL &&
epp->ep_emul_root == NULL)
emul_find_root(l, epp);
/* Any old emulation root got removed by fdcloseexec */
rw_enter(&p->p_cwdi->cwdi_lock, RW_WRITER);
p->p_cwdi->cwdi_edir = epp->ep_emul_root;
rw_exit(&p->p_cwdi->cwdi_lock);
epp->ep_emul_root = NULL;
if (epp->ep_interp != NULL)
vrele(epp->ep_interp);
/*
* Call emulation specific exec hook. This can setup per-process
* p->p_emuldata or do any other per-process stuff an emulation needs.
*
* If we are executing process of different emulation than the
* original forked process, call e_proc_exit() of the old emulation
* first, then e_proc_exec() of new emulation. If the emulation is
* same, the exec hook code should deallocate any old emulation
* resources held previously by this process.
*/
if (p->p_emul && p->p_emul->e_proc_exit
&& p->p_emul != epp->ep_esch->es_emul)
(*p->p_emul->e_proc_exit)(p);
/*
* Call exec hook. Emulation code may NOT store reference to anything
* from &pack.
*/
if (epp->ep_esch->es_emul->e_proc_exec)
(*epp->ep_esch->es_emul->e_proc_exec)(p, epp);
/* update p_emul, the old value is no longer needed */
p->p_emul = epp->ep_esch->es_emul;
/* ...and the same for p_execsw */
p->p_execsw = epp->ep_esch;
#ifdef __HAVE_SYSCALL_INTERN
(*p->p_emul->e_syscall_intern)(p);
#endif
ktremul();
}
static int
execve_runproc(struct lwp *l, struct execve_data * restrict data,
bool no_local_exec_lock, bool is_spawn)
{
struct exec_package * const epp = &data->ed_pack;
int error = 0;
struct proc *p;
struct vmspace *vm;
/*
* In case of a posix_spawn operation, the child doing the exec
* might not hold the reader lock on exec_lock, but the parent
* will do this instead.
*/
KASSERT(no_local_exec_lock || rw_lock_held(&exec_lock));
KASSERT(!no_local_exec_lock || is_spawn);
KASSERT(data != NULL);
p = l->l_proc;
/* Get rid of other LWPs. */
if (p->p_nlwps > 1) {
mutex_enter(p->p_lock);
exit_lwps(l);
mutex_exit(p->p_lock);
}
KDASSERT(p->p_nlwps == 1);
/* Destroy any lwpctl info. */
if (p->p_lwpctl != NULL)
lwp_ctl_exit();
/* Remove POSIX timers */
timers_free(p, TIMERS_POSIX);
/* Set the PaX flags. */
pax_set_flags(epp, p);
/*
* Do whatever is necessary to prepare the address space
* for remapping. Note that this might replace the current
* vmspace with another!
*
* vfork(): do not touch any user space data in the new child
* until we have awoken the parent below, or it will defeat
* lazy pmap switching (on x86).
*/
if (is_spawn)
uvmspace_spawn(l, epp->ep_vm_minaddr,
epp->ep_vm_maxaddr,
epp->ep_flags & EXEC_TOPDOWN_VM);
else
uvmspace_exec(l, epp->ep_vm_minaddr,
epp->ep_vm_maxaddr,
epp->ep_flags & EXEC_TOPDOWN_VM);
vm = p->p_vmspace;
vm->vm_taddr = (void *)epp->ep_taddr;
vm->vm_tsize = btoc(epp->ep_tsize);
vm->vm_daddr = (void*)epp->ep_daddr;
vm->vm_dsize = btoc(epp->ep_dsize);
vm->vm_ssize = btoc(epp->ep_ssize);
vm->vm_issize = 0;
vm->vm_maxsaddr = (void *)epp->ep_maxsaddr;
vm->vm_minsaddr = (void *)epp->ep_minsaddr;
pax_aslr_init_vm(l, vm, epp);
cwdexec(p);
fd_closeexec(); /* handle close on exec */
if (__predict_false(ktrace_on))
fd_ktrexecfd();
execsigs(p); /* reset caught signals */
mutex_enter(p->p_lock);
l->l_ctxlink = NULL; /* reset ucontext link */
p->p_acflag &= ~AFORK;
p->p_flag |= PK_EXEC;
mutex_exit(p->p_lock);
error = credexec(l, &data->ed_attr);
if (error)
goto exec_abort;
#if defined(__HAVE_RAS)
/*
* Remove all RASs from the address space.
*/
ras_purgeall();
#endif
/*
* Stop profiling.
*/
if ((p->p_stflag & PST_PROFIL) != 0) {
mutex_spin_enter(&p->p_stmutex);
stopprofclock(p);
mutex_spin_exit(&p->p_stmutex);
}
/*
* It's OK to test PL_PPWAIT unlocked here, as other LWPs have
* exited and exec()/exit() are the only places it will be cleared.
*
* Once the parent has been awoken, curlwp may teleport to a new CPU
* in sched_vforkexec(), and it's then OK to start messing with user
* data. See comment above.
*/
if ((p->p_lflag & PL_PPWAIT) != 0) {
bool samecpu;
lwp_t *lp;
mutex_enter(&proc_lock);
lp = p->p_vforklwp;
p->p_vforklwp = NULL;
l->l_lwpctl = NULL; /* was on loan from blocked parent */
cv_broadcast(&lp->l_waitcv);
/* Clear flags after cv_broadcast() (scheduler needs them). */
p->p_lflag &= ~PL_PPWAIT;
lp->l_vforkwaiting = false;
/* If parent is still on same CPU, teleport curlwp elsewhere. */
samecpu = (lp->l_cpu == curlwp->l_cpu);
mutex_exit(&proc_lock);
/* Give the parent its CPU back - find a new home. */
KASSERT(!is_spawn);
sched_vforkexec(l, samecpu);
}
/* Now map address space. */
error = execve_dovmcmds(l, data);
if (error != 0)
goto exec_abort;
pathexec(p, epp->ep_resolvedname);
char * const newstack = STACK_GROW(vm->vm_minsaddr, epp->ep_ssize);
error = copyoutargs(data, l, newstack);
if (error != 0)
goto exec_abort;
doexechooks(p);
/*
* Set initial SP at the top of the stack.
*
* Note that on machines where stack grows up (e.g. hppa), SP points to
* the end of arg/env strings. Userland guesses the address of argc
* via ps_strings::ps_argvstr.
*/
/* Setup new registers and do misc. setup. */
(*epp->ep_esch->es_emul->e_setregs)(l, epp, (vaddr_t)newstack);
if (epp->ep_esch->es_setregs)
(*epp->ep_esch->es_setregs)(l, epp, (vaddr_t)newstack);
/* Provide a consistent LWP private setting */
(void)lwp_setprivate(l, NULL);
/* Discard all PCU state; need to start fresh */
pcu_discard_all(l);
/* map the process's signal trampoline code */
if ((error = exec_sigcode_map(p, epp->ep_esch->es_emul)) != 0) {
DPRINTF(("%s: map sigcode failed %d\n", __func__, error));
goto exec_abort;
}
pool_put(&exec_pool, data->ed_argp);
/* notify others that we exec'd */
KNOTE(&p->p_klist, NOTE_EXEC);
kmem_free(epp->ep_hdr, epp->ep_hdrlen);
SDT_PROBE(proc, kernel, , exec__success, epp->ep_kname, 0, 0, 0, 0);
emulexec(l, epp);
/* Allow new references from the debugger/procfs. */
rw_exit(&p->p_reflock);
if (!no_local_exec_lock)
rw_exit(&exec_lock);
mutex_enter(&proc_lock);
/* posix_spawn(3) reports a single event with implied exec(3) */
if ((p->p_slflag & PSL_TRACED) && !is_spawn) {
mutex_enter(p->p_lock);
eventswitch(TRAP_EXEC, 0, 0);
mutex_enter(&proc_lock);
}
if (p->p_sflag & PS_STOPEXEC) {
ksiginfoq_t kq;
KERNEL_UNLOCK_ALL(l, &l->l_biglocks);
p->p_pptr->p_nstopchild++;
p->p_waited = 0;
mutex_enter(p->p_lock);
ksiginfo_queue_init(&kq);
sigclearall(p, &contsigmask, &kq);
lwp_lock(l);
l->l_stat = LSSTOP;
p->p_stat = SSTOP;
p->p_nrlwps--;
lwp_unlock(l);
mutex_exit(p->p_lock);
mutex_exit(&proc_lock);
lwp_lock(l);
spc_lock(l->l_cpu);
mi_switch(l);
ksiginfo_queue_drain(&kq);
} else {
mutex_exit(&proc_lock);
}
exec_path_free(data);
#ifdef TRACE_EXEC
DPRINTF(("%s finished\n", __func__));
#endif
return EJUSTRETURN;
exec_abort:
SDT_PROBE(proc, kernel, , exec__failure, error, 0, 0, 0, 0);
rw_exit(&p->p_reflock);
if (!no_local_exec_lock)
rw_exit(&exec_lock);
exec_path_free(data);
/*
* the old process doesn't exist anymore. exit gracefully.
* get rid of the (new) address space we have created, if any, get rid
* of our namei data and vnode, and exit noting failure
*/
if (vm != NULL) {
uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS,
VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS);
}
exec_free_emul_arg(epp);
pool_put(&exec_pool, data->ed_argp);
kmem_free(epp->ep_hdr, epp->ep_hdrlen);
if (epp->ep_emul_root != NULL)
vrele(epp->ep_emul_root);
if (epp->ep_interp != NULL)
vrele(epp->ep_interp);
/* Acquire the sched-state mutex (exit1() will release it). */
if (!is_spawn) {
mutex_enter(p->p_lock);
exit1(l, error, SIGABRT);
}
return error;
}
int
execve1(struct lwp *l, bool has_path, const char *path, int fd,
char * const *args, char * const *envs,
execve_fetch_element_t fetch_element)
{
struct execve_data data;
int error;
error = execve_loadvm(l, has_path, path, fd, args, envs, fetch_element,
&data);
if (error)
return error;
error = execve_runproc(l, &data, false, false);
return error;
}
static size_t
fromptrsz(const struct exec_package *epp)
{
return (epp->ep_flags & EXEC_FROM32) ? sizeof(int) : sizeof(char *);
}
static size_t
ptrsz(const struct exec_package *epp)
{
return (epp->ep_flags & EXEC_32) ? sizeof(int) : sizeof(char *);
}
static size_t
calcargs(struct execve_data * restrict data, const size_t argenvstrlen)
{
struct exec_package * const epp = &data->ed_pack;
const size_t nargenvptrs =
1 + /* long argc */
data->ed_argc + /* char *argv[] */
1 + /* \0 */
data->ed_envc + /* char *env[] */
1; /* \0 */
return (nargenvptrs * ptrsz(epp)) /* pointers */
+ argenvstrlen /* strings */
+ epp->ep_esch->es_arglen; /* auxinfo */
}
static size_t
calcstack(struct execve_data * restrict data, const size_t gaplen)
{
struct exec_package * const epp = &data->ed_pack;
data->ed_szsigcode = epp->ep_esch->es_emul->e_esigcode -
epp->ep_esch->es_emul->e_sigcode;
data->ed_ps_strings_sz = (epp->ep_flags & EXEC_32) ?
sizeof(struct ps_strings32) : sizeof(struct ps_strings);
const size_t sigcode_psstr_sz =
data->ed_szsigcode + /* sigcode */
data->ed_ps_strings_sz + /* ps_strings */
STACK_PTHREADSPACE; /* pthread space */
const size_t stacklen =
data->ed_argslen +
gaplen +
sigcode_psstr_sz;
/* make the stack "safely" aligned */
return STACK_LEN_ALIGN(stacklen, STACK_ALIGNBYTES);
}
static int
copyoutargs(struct execve_data * restrict data, struct lwp *l,
char * const newstack)
{
struct exec_package * const epp = &data->ed_pack;
struct proc *p = l->l_proc;
int error;
memset(&data->ed_arginfo, 0, sizeof(data->ed_arginfo));
/* remember information about the process */
data->ed_arginfo.ps_nargvstr = data->ed_argc;
data->ed_arginfo.ps_nenvstr = data->ed_envc;
/*
* Allocate the stack address passed to the newly execve()'ed process.
*
* The new stack address will be set to the SP (stack pointer) register
* in setregs().
*/
char *newargs = STACK_ALLOC(
STACK_SHRINK(newstack, data->ed_argslen), data->ed_argslen);
error = (*epp->ep_esch->es_copyargs)(l, epp,
&data->ed_arginfo, &newargs, data->ed_argp);
if (error) {
DPRINTF(("%s: copyargs failed %d\n", __func__, error));
return error;
}
error = copyoutpsstrs(data, p);
if (error != 0)
return error;
return 0;
}
static int
copyoutpsstrs(struct execve_data * restrict data, struct proc *p)
{
struct exec_package * const epp = &data->ed_pack;
struct ps_strings32 arginfo32;
void *aip;
int error;
/* fill process ps_strings info */
p->p_psstrp = (vaddr_t)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr,
STACK_PTHREADSPACE), data->ed_ps_strings_sz);
if (epp->ep_flags & EXEC_32) {
aip = &arginfo32;
arginfo32.ps_argvstr = (vaddr_t)data->ed_arginfo.ps_argvstr;
arginfo32.ps_nargvstr = data->ed_arginfo.ps_nargvstr;
arginfo32.ps_envstr = (vaddr_t)data->ed_arginfo.ps_envstr;
arginfo32.ps_nenvstr = data->ed_arginfo.ps_nenvstr;
} else
aip = &data->ed_arginfo;
/* copy out the process's ps_strings structure */
if ((error = copyout(aip, (void *)p->p_psstrp, data->ed_ps_strings_sz))
!= 0) {
DPRINTF(("%s: ps_strings copyout %p->%p size %zu failed\n",
__func__, aip, (void *)p->p_psstrp, data->ed_ps_strings_sz));
return error;
}
return 0;
}
static int
copyinargs(struct execve_data * restrict data, char * const *args,
char * const *envs, execve_fetch_element_t fetch_element, char **dpp)
{
struct exec_package * const epp = &data->ed_pack;
char *dp;
size_t i;
int error;
dp = *dpp;
data->ed_argc = 0;
/* copy the fake args list, if there's one, freeing it as we go */
if (epp->ep_flags & EXEC_HASARGL) {
struct exec_fakearg *fa = epp->ep_fa;
while (fa->fa_arg != NULL) {
const size_t maxlen = ARG_MAX - (dp - data->ed_argp);
size_t len;
len = strlcpy(dp, fa->fa_arg, maxlen);
/* Count NUL into len. */
if (len < maxlen)
len++;
else {
while (fa->fa_arg != NULL) {
kmem_free(fa->fa_arg, fa->fa_len);
fa++;
}
kmem_free(epp->ep_fa, epp->ep_fa_len);
epp->ep_flags &= ~EXEC_HASARGL;
return E2BIG;
}
ktrexecarg(fa->fa_arg, len - 1);
dp += len;
kmem_free(fa->fa_arg, fa->fa_len);
fa++;
data->ed_argc++;
}
kmem_free(epp->ep_fa, epp->ep_fa_len);
epp->ep_flags &= ~EXEC_HASARGL;
}
/*
* Read and count argument strings from user.
*/
if (args == NULL) {
DPRINTF(("%s: null args\n", __func__));
return EINVAL;
}
if (epp->ep_flags & EXEC_SKIPARG)
args = (const void *)((const char *)args + fromptrsz(epp));
i = 0;
error = copyinargstrs(data, args, fetch_element, &dp, &i, ktr_execarg);
if (error != 0) {
DPRINTF(("%s: copyin arg %d\n", __func__, error));
return error;
}
data->ed_argc += i;
/*
* Read and count environment strings from user.
*/
data->ed_envc = 0;
/* environment need not be there */
if (envs == NULL)
goto done;
i = 0;
error = copyinargstrs(data, envs, fetch_element, &dp, &i, ktr_execenv);
if (error != 0) {
DPRINTF(("%s: copyin env %d\n", __func__, error));
return error;
}
data->ed_envc += i;
done:
*dpp = dp;
return 0;
}
static int
copyinargstrs(struct execve_data * restrict data, char * const *strs,
execve_fetch_element_t fetch_element, char **dpp, size_t *ip,
void (*ktr)(const void *, size_t))
{
char *dp, *sp;
size_t i;
int error;
dp = *dpp;
i = 0;
while (1) {
const size_t maxlen = ARG_MAX - (dp - data->ed_argp);
size_t len;
if ((error = (*fetch_element)(strs, i, &sp)) != 0) {
return error;
}
if (!sp)
break;
if ((error = copyinstr(sp, dp, maxlen, &len)) != 0) {
if (error == ENAMETOOLONG)
error = E2BIG;
return error;
}
if (__predict_false(ktrace_on))
(*ktr)(dp, len - 1);
dp += len;
i++;
}
*dpp = dp;
*ip = i;
return 0;
}
/*
* Copy argv and env strings from kernel buffer (argp) to the new stack.
* Those strings are located just after auxinfo.
*/
int
copyargs(struct lwp *l, struct exec_package *pack, struct ps_strings *arginfo,
char **stackp, void *argp)
{
char **cpp, *dp, *sp;
size_t len;
void *nullp;
long argc, envc;
int error;
cpp = (char **)*stackp;
nullp = NULL;
argc = arginfo->ps_nargvstr;
envc = arginfo->ps_nenvstr;
/* argc on stack is long */
CTASSERT(sizeof(*cpp) == sizeof(argc));
dp = (char *)(cpp +
1 + /* long argc */
argc + /* char *argv[] */
1 + /* \0 */
envc + /* char *env[] */
1) + /* \0 */
pack->ep_esch->es_arglen; /* auxinfo */
sp = argp;
if ((error = copyout(&argc, cpp++, sizeof(argc))) != 0) {
COPYPRINTF("", cpp - 1, sizeof(argc));
return error;
}
/* XXX don't copy them out, remap them! */
arginfo->ps_argvstr = cpp; /* remember location of argv for later */
for (; --argc >= 0; sp += len, dp += len) {
if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0) {
COPYPRINTF("", cpp - 1, sizeof(dp));
return error;
}
if ((error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) {
COPYPRINTF("str", dp, (size_t)ARG_MAX);
return error;
}
}
if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) {
COPYPRINTF("", cpp - 1, sizeof(nullp));
return error;
}
arginfo->ps_envstr = cpp; /* remember location of envp for later */
for (; --envc >= 0; sp += len, dp += len) {
if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0) {
COPYPRINTF("", cpp - 1, sizeof(dp));
return error;
}
if ((error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) {
COPYPRINTF("str", dp, (size_t)ARG_MAX);
return error;
}
}
if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) {
COPYPRINTF("", cpp - 1, sizeof(nullp));
return error;
}
*stackp = (char *)cpp;
return 0;
}
/*
* Add execsw[] entries.
*/
int
exec_add(struct execsw *esp, int count)
{
struct exec_entry *it;
int i;
if (count == 0) {
return 0;
}
/* Check for duplicates. */
rw_enter(&exec_lock, RW_WRITER);
for (i = 0; i < count; i++) {
LIST_FOREACH(it, &ex_head, ex_list) {
/* assume unique (makecmds, probe_func, emulation) */
if (it->ex_sw->es_makecmds == esp[i].es_makecmds &&
it->ex_sw->u.elf_probe_func ==
esp[i].u.elf_probe_func &&
it->ex_sw->es_emul == esp[i].es_emul) {
rw_exit(&exec_lock);
return EEXIST;
}
}
}
/* Allocate new entries. */
for (i = 0; i < count; i++) {
it = kmem_alloc(sizeof(*it), KM_SLEEP);
it->ex_sw = &esp[i];
LIST_INSERT_HEAD(&ex_head, it, ex_list);
}
/* update execsw[] */
exec_init(0);
rw_exit(&exec_lock);
return 0;
}
/*
* Remove execsw[] entry.
*/
int
exec_remove(struct execsw *esp, int count)
{
struct exec_entry *it, *next;
int i;
const struct proclist_desc *pd;
proc_t *p;
if (count == 0) {
return 0;
}
/* Abort if any are busy. */
rw_enter(&exec_lock, RW_WRITER);
for (i = 0; i < count; i++) {
mutex_enter(&proc_lock);
for (pd = proclists; pd->pd_list != NULL; pd++) {
PROCLIST_FOREACH(p, pd->pd_list) {
if (p->p_execsw == &esp[i]) {
mutex_exit(&proc_lock);
rw_exit(&exec_lock);
return EBUSY;
}
}
}
mutex_exit(&proc_lock);
}
/* None are busy, so remove them all. */
for (i = 0; i < count; i++) {
for (it = LIST_FIRST(&ex_head); it != NULL; it = next) {
next = LIST_NEXT(it, ex_list);
if (it->ex_sw == &esp[i]) {
LIST_REMOVE(it, ex_list);
kmem_free(it, sizeof(*it));
break;
}
}
}
/* update execsw[] */
exec_init(0);
rw_exit(&exec_lock);
return 0;
}
/*
* Initialize exec structures. If init_boot is true, also does necessary
* one-time initialization (it's called from main() that way).
* Once system is multiuser, this should be called with exec_lock held,
* i.e. via exec_{add|remove}().
*/
int
exec_init(int init_boot)
{
const struct execsw **sw;
struct exec_entry *ex;
SLIST_HEAD(,exec_entry) first;
SLIST_HEAD(,exec_entry) any;
SLIST_HEAD(,exec_entry) last;
int i, sz;
if (init_boot) {
/* do one-time initializations */
vaddr_t vmin = 0, vmax;
rw_init(&exec_lock);
mutex_init(&sigobject_lock, MUTEX_DEFAULT, IPL_NONE);
exec_map = uvm_km_suballoc(kernel_map, &vmin, &vmax,
maxexec*NCARGS, VM_MAP_PAGEABLE, false, NULL);
pool_init(&exec_pool, NCARGS, 0, 0, PR_NOALIGN|PR_NOTOUCH,
"execargs", &exec_palloc, IPL_NONE);
pool_sethardlimit(&exec_pool, maxexec, "should not happen", 0);
} else {
KASSERT(rw_write_held(&exec_lock));
}
/* Sort each entry onto the appropriate queue. */
SLIST_INIT(&first);
SLIST_INIT(&any);
SLIST_INIT(&last);
sz = 0;
LIST_FOREACH(ex, &ex_head, ex_list) {
switch(ex->ex_sw->es_prio) {
case EXECSW_PRIO_FIRST:
SLIST_INSERT_HEAD(&first, ex, ex_slist);
break;
case EXECSW_PRIO_ANY:
SLIST_INSERT_HEAD(&any, ex, ex_slist);
break;
case EXECSW_PRIO_LAST:
SLIST_INSERT_HEAD(&last, ex, ex_slist);
break;
default:
panic("%s", __func__);
break;
}
sz++;
}
/*
* Create new execsw[]. Ensure we do not try a zero-sized
* allocation.
*/
sw = kmem_alloc(sz * sizeof(struct execsw *) + 1, KM_SLEEP);
i = 0;
SLIST_FOREACH(ex, &first, ex_slist) {
sw[i++] = ex->ex_sw;
}
SLIST_FOREACH(ex, &any, ex_slist) {
sw[i++] = ex->ex_sw;
}
SLIST_FOREACH(ex, &last, ex_slist) {
sw[i++] = ex->ex_sw;
}
/* Replace old execsw[] and free used memory. */
if (execsw != NULL) {
kmem_free(__UNCONST(execsw),
nexecs * sizeof(struct execsw *) + 1);
}
execsw = sw;
nexecs = sz;
/* Figure out the maximum size of an exec header. */
exec_maxhdrsz = sizeof(int);
for (i = 0; i < nexecs; i++) {
if (execsw[i]->es_hdrsz > exec_maxhdrsz)
exec_maxhdrsz = execsw[i]->es_hdrsz;
}
return 0;
}
static int
exec_sigcode_map(struct proc *p, const struct emul *e)
{
vaddr_t va;
vsize_t sz;
int error;
struct uvm_object *uobj;
sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode;
if (e->e_sigobject == NULL || sz == 0) {
return 0;
}
/*
* If we don't have a sigobject for this emulation, create one.
*
* sigobject is an anonymous memory object (just like SYSV shared
* memory) that we keep a permanent reference to and that we map
* in all processes that need this sigcode. The creation is simple,
* we create an object, add a permanent reference to it, map it in
* kernel space, copy out the sigcode to it and unmap it.
* We map it with PROT_READ|PROT_EXEC into the process just
* the way sys_mmap() would map it.
*/
uobj = *e->e_sigobject;
if (uobj == NULL) {
mutex_enter(&sigobject_lock);
if ((uobj = *e->e_sigobject) == NULL) {
uobj = uao_create(sz, 0);
(*uobj->pgops->pgo_reference)(uobj);
va = vm_map_min(kernel_map);
if ((error = uvm_map(kernel_map, &va, round_page(sz),
uobj, 0, 0,
UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW,
UVM_INH_SHARE, UVM_ADV_RANDOM, 0)))) {
printf("kernel mapping failed %d\n", error);
(*uobj->pgops->pgo_detach)(uobj);
mutex_exit(&sigobject_lock);
return error;
}
memcpy((void *)va, e->e_sigcode, sz);
#ifdef PMAP_NEED_PROCWR
pmap_procwr(&proc0, va, sz);
#endif
uvm_unmap(kernel_map, va, va + round_page(sz));
*e->e_sigobject = uobj;
}
mutex_exit(&sigobject_lock);
}
/* Just a hint to uvm_map where to put it. */
va = e->e_vm_default_addr(p, (vaddr_t)p->p_vmspace->vm_daddr,
round_page(sz), p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN);
#ifdef __alpha__
/*
* Tru64 puts /sbin/loader at the end of user virtual memory,
* which causes the above calculation to put the sigcode at
* an invalid address. Put it just below the text instead.
*/
if (va == (vaddr_t)vm_map_max(&p->p_vmspace->vm_map)) {
va = (vaddr_t)p->p_vmspace->vm_taddr - round_page(sz);
}
#endif
(*uobj->pgops->pgo_reference)(uobj);
error = uvm_map(&p->p_vmspace->vm_map, &va, round_page(sz),
uobj, 0, 0,
UVM_MAPFLAG(UVM_PROT_RX, UVM_PROT_RX, UVM_INH_SHARE,
UVM_ADV_RANDOM, 0));
if (error) {
DPRINTF(("%s, %d: map %p "
"uvm_map %#"PRIxVSIZE"@%#"PRIxVADDR" failed %d\n",
__func__, __LINE__, &p->p_vmspace->vm_map, round_page(sz),
va, error));
(*uobj->pgops->pgo_detach)(uobj);
return error;
}
p->p_sigctx.ps_sigcode = (void *)va;
return 0;
}
/*
* Release a refcount on spawn_exec_data and destroy memory, if this
* was the last one.
*/
static void
spawn_exec_data_release(struct spawn_exec_data *data)
{
if (atomic_dec_32_nv(&data->sed_refcnt) != 0)
return;
cv_destroy(&data->sed_cv_child_ready);
mutex_destroy(&data->sed_mtx_child);
if (data->sed_actions)
posix_spawn_fa_free(data->sed_actions,
data->sed_actions->len);
if (data->sed_attrs)
kmem_free(data->sed_attrs,
sizeof(*data->sed_attrs));
kmem_free(data, sizeof(*data));
}
static int
handle_posix_spawn_file_actions(struct posix_spawn_file_actions *actions)
{
struct lwp *l = curlwp;
register_t retval;
int error, newfd;
if (actions == NULL)
return 0;
for (size_t i = 0; i < actions->len; i++) {
const struct posix_spawn_file_actions_entry *fae =
&actions->fae[i];
switch (fae->fae_action) {
case FAE_OPEN:
if (fd_getfile(fae->fae_fildes) != NULL) {
error = fd_close(fae->fae_fildes);
if (error)
return error;
}
error = fd_open(fae->fae_path, fae->fae_oflag,
fae->fae_mode, &newfd);
if (error)
return error;
if (newfd != fae->fae_fildes) {
error = dodup(l, newfd,
fae->fae_fildes, 0, &retval);
if (fd_getfile(newfd) != NULL)
fd_close(newfd);
}
break;
case FAE_DUP2:
error = dodup(l, fae->fae_fildes,
fae->fae_newfildes, 0, &retval);
break;
case FAE_CLOSE:
if (fd_getfile(fae->fae_fildes) == NULL) {
return EBADF;
}
error = fd_close(fae->fae_fildes);
break;
}
if (error)
return error;
}
return 0;
}
static int
handle_posix_spawn_attrs(struct posix_spawnattr *attrs, struct proc *parent)
{
struct sigaction sigact;
int error;
struct proc *p = curproc;
struct lwp *l = curlwp;
if (attrs == NULL)
return 0;
memset(&sigact, 0, sizeof(sigact));
sigact._sa_u._sa_handler = SIG_DFL;
sigact.sa_flags = 0;
/*
* set state to SSTOP so that this proc can be found by pid.
* see proc_enterprp, do_sched_setparam below
*/
mutex_enter(&proc_lock);
/*
* p_stat should be SACTIVE, so we need to adjust the
* parent's p_nstopchild here. For safety, just make
* we're on the good side of SDEAD before we adjust.
*/
int ostat = p->p_stat;
KASSERT(ostat < SSTOP);
p->p_stat = SSTOP;
p->p_waited = 0;
p->p_pptr->p_nstopchild++;
mutex_exit(&proc_lock);
/* Set process group */
if (attrs->sa_flags & POSIX_SPAWN_SETPGROUP) {
pid_t mypid = p->p_pid;
pid_t pgrp = attrs->sa_pgroup;
if (pgrp == 0)
pgrp = mypid;
error = proc_enterpgrp(parent, mypid, pgrp, false);
if (error)
goto out;
}
/* Set scheduler policy */
if (attrs->sa_flags & POSIX_SPAWN_SETSCHEDULER)
error = do_sched_setparam(p->p_pid, 0, attrs->sa_schedpolicy,
&attrs->sa_schedparam);
else if (attrs->sa_flags & POSIX_SPAWN_SETSCHEDPARAM) {
error = do_sched_setparam(parent->p_pid, 0,
SCHED_NONE, &attrs->sa_schedparam);
}
if (error)
goto out;
/* Reset user ID's */
if (attrs->sa_flags & POSIX_SPAWN_RESETIDS) {
error = do_setresuid(l, -1, kauth_cred_getgid(l->l_cred), -1,
ID_E_EQ_R | ID_E_EQ_S);
if (error)
return error;
error = do_setresuid(l, -1, kauth_cred_getuid(l->l_cred), -1,
ID_E_EQ_R | ID_E_EQ_S);
if (error)
goto out;
}
/* Set signal masks/defaults */
if (attrs->sa_flags & POSIX_SPAWN_SETSIGMASK) {
mutex_enter(p->p_lock);
error = sigprocmask1(l, SIG_SETMASK, &attrs->sa_sigmask, NULL);
mutex_exit(p->p_lock);
if (error)
goto out;
}
if (attrs->sa_flags & POSIX_SPAWN_SETSIGDEF) {
/*
* The following sigaction call is using a sigaction
* version 0 trampoline which is in the compatibility
* code only. This is not a problem because for SIG_DFL
* and SIG_IGN, the trampolines are now ignored. If they
* were not, this would be a problem because we are
* holding the exec_lock, and the compat code needs
* to do the same in order to replace the trampoline
* code of the process.
*/
for (int i = 1; i <= NSIG; i++) {
if (sigismember(&attrs->sa_sigdefault, i))
sigaction1(l, i, &sigact, NULL, NULL, 0);
}
}
error = 0;
out:
mutex_enter(&proc_lock);
p->p_stat = ostat;
p->p_pptr->p_nstopchild--;
mutex_exit(&proc_lock);
return error;
}
/*
* A child lwp of a posix_spawn operation starts here and ends up in
* cpu_spawn_return, dealing with all filedescriptor and scheduler
* manipulations in between.
* The parent waits for the child, as it is not clear whether the child
* will be able to acquire its own exec_lock. If it can, the parent can
* be released early and continue running in parallel. If not (or if the
* magic debug flag is passed in the scheduler attribute struct), the
* child rides on the parent's exec lock until it is ready to return to
* to userland - and only then releases the parent. This method loses
* concurrency, but improves error reporting.
*/
static void
spawn_return(void *arg)
{
struct spawn_exec_data *spawn_data = arg;
struct lwp *l = curlwp;
struct proc *p = l->l_proc;
int error;
bool have_reflock;
bool parent_is_waiting = true;
/*
* Check if we can release parent early.
* We either need to have no sed_attrs, or sed_attrs does not
* have POSIX_SPAWN_RETURNERROR or one of the flags, that require
* safe access to the parent proc (passed in sed_parent).
* We then try to get the exec_lock, and only if that works, we can
* release the parent here already.
*/
struct posix_spawnattr *attrs = spawn_data->sed_attrs;
if ((!attrs || (attrs->sa_flags
& (POSIX_SPAWN_RETURNERROR|POSIX_SPAWN_SETPGROUP)) == 0)
&& rw_tryenter(&exec_lock, RW_READER)) {
parent_is_waiting = false;
mutex_enter(&spawn_data->sed_mtx_child);
cv_signal(&spawn_data->sed_cv_child_ready);
mutex_exit(&spawn_data->sed_mtx_child);
}
/* don't allow debugger access yet */
rw_enter(&p->p_reflock, RW_WRITER);
have_reflock = true;
/* handle posix_spawn_file_actions */
error = handle_posix_spawn_file_actions(spawn_data->sed_actions);
if (error)
goto report_error;
/* handle posix_spawnattr */
error = handle_posix_spawn_attrs(attrs, spawn_data->sed_parent);
if (error)
goto report_error;
/* now do the real exec */
error = execve_runproc(l, &spawn_data->sed_exec, parent_is_waiting,
true);
have_reflock = false;
if (error == EJUSTRETURN)
error = 0;
else if (error)
goto report_error;
if (parent_is_waiting) {
mutex_enter(&spawn_data->sed_mtx_child);
cv_signal(&spawn_data->sed_cv_child_ready);
mutex_exit(&spawn_data->sed_mtx_child);
}
/* release our refcount on the data */
spawn_exec_data_release(spawn_data);
if ((p->p_slflag & (PSL_TRACED|PSL_TRACEDCHILD)) ==
(PSL_TRACED|PSL_TRACEDCHILD)) {
eventswitchchild(p, TRAP_CHLD, PTRACE_POSIX_SPAWN);
}
/* and finally: leave to userland for the first time */
cpu_spawn_return(l);
/* NOTREACHED */
return;
report_error:
if (have_reflock) {
/*
* We have not passed through execve_runproc(),
* which would have released the p_reflock and also
* taken ownership of the sed_exec part of spawn_data,
* so release/free both here.
*/
rw_exit(&p->p_reflock);
execve_free_data(&spawn_data->sed_exec);
}
if (parent_is_waiting) {
/* pass error to parent */
mutex_enter(&spawn_data->sed_mtx_child);
spawn_data->sed_error = error;
cv_signal(&spawn_data->sed_cv_child_ready);
mutex_exit(&spawn_data->sed_mtx_child);
} else {
rw_exit(&exec_lock);
}
/* release our refcount on the data */
spawn_exec_data_release(spawn_data);
/* done, exit */
mutex_enter(p->p_lock);
/*
* Posix explicitly asks for an exit code of 127 if we report
* errors from the child process - so, unfortunately, there
* is no way to report a more exact error code.
* A NetBSD specific workaround is POSIX_SPAWN_RETURNERROR as
* flag bit in the attrp argument to posix_spawn(2), see above.
*/
exit1(l, 127, 0);
}
void
posix_spawn_fa_free(struct posix_spawn_file_actions *fa, size_t len)
{
for (size_t i = 0; i < len; i++) {
struct posix_spawn_file_actions_entry *fae = &fa->fae[i];
if (fae->fae_action != FAE_OPEN)
continue;
kmem_strfree(fae->fae_path);
}
if (fa->len > 0)
kmem_free(fa->fae, sizeof(*fa->fae) * fa->len);
kmem_free(fa, sizeof(*fa));
}
static int
posix_spawn_fa_alloc(struct posix_spawn_file_actions **fap,
const struct posix_spawn_file_actions *ufa, rlim_t lim)
{
struct posix_spawn_file_actions *fa;
struct posix_spawn_file_actions_entry *fae;
char *pbuf = NULL;
int error;
size_t i = 0;
fa = kmem_alloc(sizeof(*fa), KM_SLEEP);
error = copyin(ufa, fa, sizeof(*fa));
if (error || fa->len == 0) {
kmem_free(fa, sizeof(*fa));
return error; /* 0 if not an error, and len == 0 */
}
if (fa->len > lim) {
kmem_free(fa, sizeof(*fa));
return EINVAL;
}
fa->size = fa->len;
size_t fal = fa->len * sizeof(*fae);
fae = fa->fae;
fa->fae = kmem_alloc(fal, KM_SLEEP);
error = copyin(fae, fa->fae, fal);
if (error)
goto out;
pbuf = PNBUF_GET();
for (; i < fa->len; i++) {
fae = &fa->fae[i];
if (fae->fae_action != FAE_OPEN)
continue;
error = copyinstr(fae->fae_path, pbuf, MAXPATHLEN, &fal);
if (error)
goto out;
fae->fae_path = kmem_alloc(fal, KM_SLEEP);
memcpy(fae->fae_path, pbuf, fal);
}
PNBUF_PUT(pbuf);
*fap = fa;
return 0;
out:
if (pbuf)
PNBUF_PUT(pbuf);
posix_spawn_fa_free(fa, i);
return error;
}
/*
* N.B. increments nprocs upon success. Callers need to drop nprocs if
* they fail for some other reason.
*/
int
check_posix_spawn(struct lwp *l1)
{
int error, tnprocs, count;
uid_t uid;
struct proc *p1;
p1 = l1->l_proc;
uid = kauth_cred_getuid(l1->l_cred);
tnprocs = atomic_inc_uint_nv(&nprocs);
/*
* Although process entries are dynamically created, we still keep
* a global limit on the maximum number we will create.
*/
if (__predict_false(tnprocs >= maxproc))
error = -1;
else
error = kauth_authorize_process(l1->l_cred,
KAUTH_PROCESS_FORK, p1, KAUTH_ARG(tnprocs), NULL, NULL);
if (error) {
atomic_dec_uint(&nprocs);
return EAGAIN;
}
/*
* Enforce limits.
*/
count = chgproccnt(uid, 1);
if (kauth_authorize_process(l1->l_cred, KAUTH_PROCESS_RLIMIT,
p1, KAUTH_ARG(KAUTH_REQ_PROCESS_RLIMIT_BYPASS),
&p1->p_rlimit[RLIMIT_NPROC], KAUTH_ARG(RLIMIT_NPROC)) != 0 &&
__predict_false(count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur)) {
(void)chgproccnt(uid, -1);
atomic_dec_uint(&nprocs);
return EAGAIN;
}
return 0;
}
int
do_posix_spawn(struct lwp *l1, pid_t *pid_res, bool *child_ok, const char *path,
struct posix_spawn_file_actions *fa,
struct posix_spawnattr *sa,
char *const *argv, char *const *envp,
execve_fetch_element_t fetch)
{
struct proc *p1, *p2;
struct lwp *l2;
int error;
struct spawn_exec_data *spawn_data;
vaddr_t uaddr;
pid_t pid;
bool have_exec_lock = false;
p1 = l1->l_proc;
/* Allocate and init spawn_data */
spawn_data = kmem_zalloc(sizeof(*spawn_data), KM_SLEEP);
spawn_data->sed_refcnt = 1; /* only parent so far */
cv_init(&spawn_data->sed_cv_child_ready, "pspawn");
mutex_init(&spawn_data->sed_mtx_child, MUTEX_DEFAULT, IPL_NONE);
mutex_enter(&spawn_data->sed_mtx_child);
/*
* Do the first part of the exec now, collect state
* in spawn_data.
*/
error = execve_loadvm(l1, true, path, -1, argv,
envp, fetch, &spawn_data->sed_exec);
if (error == EJUSTRETURN)
error = 0;
else if (error)
goto error_exit;
have_exec_lock = true;
/*
* Allocate virtual address space for the U-area now, while it
* is still easy to abort the fork operation if we're out of
* kernel virtual address space.
*/
uaddr = uvm_uarea_alloc();
if (__predict_false(uaddr == 0)) {
error = ENOMEM;
goto error_exit;
}
/*
* Allocate new proc. Borrow proc0 vmspace for it, we will
* replace it with its own before returning to userland
* in the child.
*/
p2 = proc_alloc();
if (p2 == NULL) {
/* We were unable to allocate a process ID. */
error = EAGAIN;
goto error_exit;
}
/*
* This is a point of no return, we will have to go through
* the child proc to properly clean it up past this point.
*/
pid = p2->p_pid;
/*
* Make a proc table entry for the new process.
* Start by zeroing the section of proc that is zero-initialized,
* then copy the section that is copied directly from the parent.
*/
memset(&p2->p_startzero, 0,
(unsigned) ((char *)&p2->p_endzero - (char *)&p2->p_startzero));
memcpy(&p2->p_startcopy, &p1->p_startcopy,
(unsigned) ((char *)&p2->p_endcopy - (char *)&p2->p_startcopy));
p2->p_vmspace = proc0.p_vmspace;
TAILQ_INIT(&p2->p_sigpend.sp_info);
LIST_INIT(&p2->p_lwps);
LIST_INIT(&p2->p_sigwaiters);
/*
* Duplicate sub-structures as needed.
* Increase reference counts on shared objects.
* Inherit flags we want to keep. The flags related to SIGCHLD
* handling are important in order to keep a consistent behaviour
* for the child after the fork. If we are a 32-bit process, the
* child will be too.
*/
p2->p_flag =
p1->p_flag & (PK_SUGID | PK_NOCLDWAIT | PK_CLDSIGIGN | PK_32);
p2->p_emul = p1->p_emul;
p2->p_execsw = p1->p_execsw;
mutex_init(&p2->p_stmutex, MUTEX_DEFAULT, IPL_HIGH);
mutex_init(&p2->p_auxlock, MUTEX_DEFAULT, IPL_NONE);
rw_init(&p2->p_reflock);
cv_init(&p2->p_waitcv, "wait");
cv_init(&p2->p_lwpcv, "lwpwait");
p2->p_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
kauth_proc_fork(p1, p2);
p2->p_raslist = NULL;
p2->p_fd = fd_copy();
/* XXX racy */
p2->p_mqueue_cnt = p1->p_mqueue_cnt;
p2->p_cwdi = cwdinit();
/*
* Note: p_limit (rlimit stuff) is copy-on-write, so normally
* we just need increase pl_refcnt.
*/
if (!p1->p_limit->pl_writeable) {
lim_addref(p1->p_limit);
p2->p_limit = p1->p_limit;
} else {
p2->p_limit = lim_copy(p1->p_limit);
}
p2->p_lflag = 0;
l1->l_vforkwaiting = false;
p2->p_sflag = 0;
p2->p_slflag = 0;
p2->p_pptr = p1;
p2->p_ppid = p1->p_pid;
LIST_INIT(&p2->p_children);
p2->p_aio = NULL;
#ifdef KTRACE
/*
* Copy traceflag and tracefile if enabled.
* If not inherited, these were zeroed above.
*/
if (p1->p_traceflag & KTRFAC_INHERIT) {
mutex_enter(&ktrace_lock);
p2->p_traceflag = p1->p_traceflag;
if ((p2->p_tracep = p1->p_tracep) != NULL)
ktradref(p2);
mutex_exit(&ktrace_lock);
}
#endif
/*
* Create signal actions for the child process.
*/
p2->p_sigacts = sigactsinit(p1, 0);
mutex_enter(p1->p_lock);
p2->p_sflag |=
(p1->p_sflag & (PS_STOPFORK | PS_STOPEXEC | PS_NOCLDSTOP));
sched_proc_fork(p1, p2);
mutex_exit(p1->p_lock);
p2->p_stflag = p1->p_stflag;
/*
* p_stats.
* Copy parts of p_stats, and zero out the rest.
*/
p2->p_stats = pstatscopy(p1->p_stats);
/* copy over machdep flags to the new proc */
cpu_proc_fork(p1, p2);
/*
* Prepare remaining parts of spawn data
*/
spawn_data->sed_actions = fa;
spawn_data->sed_attrs = sa;
spawn_data->sed_parent = p1;
/* create LWP */
lwp_create(l1, p2, uaddr, 0, NULL, 0, spawn_return, spawn_data,
&l2, l1->l_class, &l1->l_sigmask, &l1->l_sigstk);
l2->l_ctxlink = NULL; /* reset ucontext link */
/*
* Copy the credential so other references don't see our changes.
* Test to see if this is necessary first, since in the common case
* we won't need a private reference.
*/
if (kauth_cred_geteuid(l2->l_cred) != kauth_cred_getsvuid(l2->l_cred) ||
kauth_cred_getegid(l2->l_cred) != kauth_cred_getsvgid(l2->l_cred)) {
l2->l_cred = kauth_cred_copy(l2->l_cred);
kauth_cred_setsvuid(l2->l_cred, kauth_cred_geteuid(l2->l_cred));
kauth_cred_setsvgid(l2->l_cred, kauth_cred_getegid(l2->l_cred));
}
/* Update the master credentials. */
if (l2->l_cred != p2->p_cred) {
kauth_cred_t ocred;
kauth_cred_hold(l2->l_cred);
mutex_enter(p2->p_lock);
ocred = p2->p_cred;
p2->p_cred = l2->l_cred;
mutex_exit(p2->p_lock);
kauth_cred_free(ocred);
}
*child_ok = true;
spawn_data->sed_refcnt = 2; /* child gets it as well */
#if 0
l2->l_nopreempt = 1; /* start it non-preemptable */
#endif
/*
* It's now safe for the scheduler and other processes to see the
* child process.
*/
mutex_enter(&proc_lock);
if (p1->p_session->s_ttyvp != NULL && p1->p_lflag & PL_CONTROLT)
p2->p_lflag |= PL_CONTROLT;
LIST_INSERT_HEAD(&p1->p_children, p2, p_sibling);
p2->p_exitsig = SIGCHLD; /* signal for parent on exit */
if ((p1->p_slflag & (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) ==
(PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) {
proc_changeparent(p2, p1->p_pptr);
SET(p2->p_slflag, PSL_TRACEDCHILD);
}
p2->p_oppid = p1->p_pid; /* Remember the original parent id. */
LIST_INSERT_AFTER(p1, p2, p_pglist);
LIST_INSERT_HEAD(&allproc, p2, p_list);
p2->p_trace_enabled = trace_is_enabled(p2);
#ifdef __HAVE_SYSCALL_INTERN
(*p2->p_emul->e_syscall_intern)(p2);
#endif
/*
* Make child runnable, set start time, and add to run queue except
* if the parent requested the child to start in SSTOP state.
*/
mutex_enter(p2->p_lock);
getmicrotime(&p2->p_stats->p_start);
lwp_lock(l2);
KASSERT(p2->p_nrlwps == 1);
KASSERT(l2->l_stat == LSIDL);
p2->p_nrlwps = 1;
p2->p_stat = SACTIVE;
setrunnable(l2);
/* LWP now unlocked */
mutex_exit(p2->p_lock);
mutex_exit(&proc_lock);
cv_wait(&spawn_data->sed_cv_child_ready, &spawn_data->sed_mtx_child);
error = spawn_data->sed_error;
mutex_exit(&spawn_data->sed_mtx_child);
spawn_exec_data_release(spawn_data);
rw_exit(&p1->p_reflock);
rw_exit(&exec_lock);
have_exec_lock = false;
*pid_res = pid;
if (error)
return error;
if (p1->p_slflag & PSL_TRACED) {
/* Paranoid check */
mutex_enter(&proc_lock);
if ((p1->p_slflag & (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) !=
(PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) {
mutex_exit(&proc_lock);
return 0;
}
mutex_enter(p1->p_lock);
eventswitch(TRAP_CHLD, PTRACE_POSIX_SPAWN, pid);
}
return 0;
error_exit:
if (have_exec_lock) {
execve_free_data(&spawn_data->sed_exec);
rw_exit(&p1->p_reflock);
rw_exit(&exec_lock);
}
mutex_exit(&spawn_data->sed_mtx_child);
spawn_exec_data_release(spawn_data);
return error;
}
int
sys_posix_spawn(struct lwp *l1, const struct sys_posix_spawn_args *uap,
register_t *retval)
{
/* {
syscallarg(pid_t *) pid;
syscallarg(const char *) path;
syscallarg(const struct posix_spawn_file_actions *) file_actions;
syscallarg(const struct posix_spawnattr *) attrp;
syscallarg(char *const *) argv;
syscallarg(char *const *) envp;
} */
int error;
struct posix_spawn_file_actions *fa = NULL;
struct posix_spawnattr *sa = NULL;
pid_t pid;
bool child_ok = false;
rlim_t max_fileactions;
proc_t *p = l1->l_proc;
/* check_posix_spawn() increments nprocs for us. */
error = check_posix_spawn(l1);
if (error) {
*retval = error;
return 0;
}
/* copy in file_actions struct */
if (SCARG(uap, file_actions) != NULL) {
max_fileactions = 2 * uimin(p->p_rlimit[RLIMIT_NOFILE].rlim_cur,
maxfiles);
error = posix_spawn_fa_alloc(&fa, SCARG(uap, file_actions),
max_fileactions);
if (error)
goto error_exit;
}
/* copyin posix_spawnattr struct */
if (SCARG(uap, attrp) != NULL) {
sa = kmem_alloc(sizeof(*sa), KM_SLEEP);
error = copyin(SCARG(uap, attrp), sa, sizeof(*sa));
if (error)
goto error_exit;
}
/*
* Do the spawn
*/
error = do_posix_spawn(l1, &pid, &child_ok, SCARG(uap, path), fa, sa,
SCARG(uap, argv), SCARG(uap, envp), execve_fetch_element);
if (error)
goto error_exit;
if (error == 0 && SCARG(uap, pid) != NULL)
error = copyout(&pid, SCARG(uap, pid), sizeof(pid));
*retval = error;
return 0;
error_exit:
if (!child_ok) {
(void)chgproccnt(kauth_cred_getuid(l1->l_cred), -1);
atomic_dec_uint(&nprocs);
if (sa)
kmem_free(sa, sizeof(*sa));
if (fa)
posix_spawn_fa_free(fa, fa->len);
}
*retval = error;
return 0;
}
void
exec_free_emul_arg(struct exec_package *epp)
{
if (epp->ep_emul_arg_free != NULL) {
KASSERT(epp->ep_emul_arg != NULL);
(*epp->ep_emul_arg_free)(epp->ep_emul_arg);
epp->ep_emul_arg_free = NULL;
epp->ep_emul_arg = NULL;
} else {
KASSERT(epp->ep_emul_arg == NULL);
}
}
#ifdef DEBUG_EXEC
static void
dump_vmcmds(const struct exec_package * const epp, size_t x, int error)
{
struct exec_vmcmd *vp = &epp->ep_vmcmds.evs_cmds[0];
size_t j;
if (error == 0)
DPRINTF(("vmcmds %u\n", epp->ep_vmcmds.evs_used));
else
DPRINTF(("vmcmds %zu/%u, error %d\n", x,
epp->ep_vmcmds.evs_used, error));
for (j = 0; j < epp->ep_vmcmds.evs_used; j++) {
DPRINTF(("vmcmd[%zu] = vmcmd_map_%s %#"
PRIxVADDR"/%#"PRIxVSIZE" fd@%#"
PRIxVSIZE" prot=0%o flags=%d\n", j,
vp[j].ev_proc == vmcmd_map_pagedvn ?
"pagedvn" :
vp[j].ev_proc == vmcmd_map_readvn ?
"readvn" :
vp[j].ev_proc == vmcmd_map_zero ?
"zero" : "*unknown*",
vp[j].ev_addr, vp[j].ev_len,
vp[j].ev_offset, vp[j].ev_prot,
vp[j].ev_flags));
if (error != 0 && j == x)
DPRINTF((" ^--- failed\n"));
}
}
#endif
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