/
kern_exec.c
2720 lines (2355 loc) · 68.6 KB
/
kern_exec.c
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/* $NetBSD: kern_exec.c,v 1.422 2015/11/26 13:15:34 martin Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* 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.
*
* 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 1.422 2015/11/26 13:15:34 martin 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/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;
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 *);
#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 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
.e_sysent = sysent,
#ifdef SYSCALL_DEBUG
.e_syscallnames = syscallnames,
#else
.e_syscallnames = NULL,
#endif
.e_sendsig = sendsig,
.e_trapsignal = trapsignal,
.e_tracesig = NULL,
.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_fault = 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;
static kmutex_t sigobject_lock;
/*
* 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_resolvedpathbuf;
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 void *
exec_pool_alloc(struct pool *pp, int flags)
{
return (void *)uvm_km_alloc(kernel_map, NCARGS, 0,
UVM_KMF_PAGEABLE | UVM_KMF_WAITVA);
}
static void
exec_pool_free(struct pool *pp, void *addr)
{
uvm_km_free(kernel_map, (vaddr_t)addr, NCARGS, UVM_KMF_PAGEABLE);
}
static struct pool exec_pool;
static struct pool_allocator exec_palloc = {
.pa_alloc = exec_pool_alloc,
.pa_free = exec_pool_free,
.pa_pagesz = NCARGS
};
/*
* 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)
{
int error, i;
struct vnode *vp;
struct nameidata nd;
size_t resid;
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;
/* normally this can't fail */
error = copystr(nd.ni_pnbuf, epp->ep_resolvedname, PATH_MAX, NULL);
KASSERT(error == 0);
#ifdef DIAGNOSTIC
/* paranoia (take this out once namei stuff stabilizes) */
memset(nd.ni_pnbuf, '~', PATH_MAX);
#endif
/* 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 */
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;
/* 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_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 */
/* now we have the file, get the exec header */
error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0,
UIO_SYSSPACE, 0, l->l_cred, &resid, NULL);
if (error)
goto bad2;
epp->ep_hdrvalid = epp->ep_hdrlen - resid;
/*
* Set up default address space limits. Can be overridden
* by individual exec packages.
*
* XXX probably should be all done in the exec packages.
*/
epp->ep_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);
bad2:
/*
* 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, SCARG(uap, path), 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 ENOSYS;
}
/*
* 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_freebsd",
"compat_ibcs2",
"compat_linux",
"compat_linux32",
"compat_netbsd32",
"compat_sunos",
"compat_sunos32",
"compat_svr4",
"compat_svr4_32",
"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
}
static int
makepathbuf(struct lwp *l, const char *upath, struct pathbuf **pbp,
size_t *offs)
{
char *path, *bp;
size_t len, tlen;
int error;
struct cwdinfo *cwdi;
path = PNBUF_GET();
error = copyinstr(upath, path, MAXPATHLEN, &len);
if (error) {
PNBUF_PUT(path);
DPRINTF(("%s: copyin path @%p %d\n", __func__, upath, error));
return error;
}
if (path[0] == '/') {
*offs = 0;
goto out;
}
len++;
if (len + 1 >= MAXPATHLEN)
goto out;
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) {
DPRINTF(("%s: getcwd_common path %s %d\n", __func__, path,
error));
goto out;
}
tlen = path + MAXPATHLEN - bp;
memmove(path, bp, tlen);
path[tlen] = '\0';
*offs = tlen - len;
out:
*pbp = pathbuf_assimilate(path);
return 0;
}
static int
execve_loadvm(struct lwp *l, const char *path, 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;
size_t offs = 0; // XXX: GCC
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);
/*
* 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 = makepathbuf(l, path, &data->ed_pathbuf, &offs)) != 0)
goto clrflg;
data->ed_pathstring = pathbuf_stringcopy_get(data->ed_pathbuf);
data->ed_resolvedpathbuf = PNBUF_GET();
/*
* initialize the fields of the exec package.
*/
epp->ep_kname = data->ed_pathstring + offs;
epp->ep_resolvedname = data->ed_resolvedpathbuf;
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)) != 0) {
if (error != ENOENT) {
DPRINTF(("%s: check exec failed %d\n",
__func__, 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 PAX_ASLR
#define ASLR_GAP(epp) (pax_aslr_epp_active(epp) ? (cprng_fast32() % PAGE_SIZE) : 0)
#else
#define ASLR_GAP(epp) 0
#endif
#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, ASLR_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);
pathbuf_stringcopy_put(data->ed_pathbuf, data->ed_pathstring);
pathbuf_destroy(data->ed_pathbuf);
PNBUF_PUT(data->ed_resolvedpathbuf);
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__);
DUMPVMCMDS(epp, 0, 0);
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);
pathbuf_stringcopy_put(data->ed_pathbuf, data->ed_pathstring);
pathbuf_destroy(data->ed_pathbuf);
PNBUF_PUT(data->ed_resolvedpathbuf);
}
static void
pathexec(struct exec_package *epp, struct proc *p, const char *pathstring)
{
const char *commandname;
size_t commandlen;
char *path;
/* set command name & other accounting info */
commandname = strrchr(epp->ep_resolvedname, '/');
if (commandname != NULL) {
commandname++;
} else {
commandname = epp->ep_resolvedname;
}
commandlen = min(strlen(commandname), MAXCOMLEN);
(void)memcpy(p->p_comm, commandname, commandlen);
p->p_comm[commandlen] = '\0';
/*
* If the path starts with /, we don't need to do any work.
* This handles the majority of the cases.
* In the future perhaps we could canonicalize it?
*/
if (pathstring[0] == '/') {
path = PNBUF_GET();
(void)strlcpy(path, pathstring, MAXPATHLEN);
epp->ep_path = path;
} else
epp->ep_path = NULL;
}
/* 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))