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NetBSD/sys/kern/kern_exec.c

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/* $NetBSD: kern_exec.c,v 1.78 1996/12/22 10:21:07 cgd Exp $ */
/*-
* 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/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/acct.h>
#include <sys/exec.h>
#include <sys/ktrace.h>
#include <sys/resourcevar.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#ifdef SYSVSHM
#include <sys/shm.h>
#endif
#include <sys/syscallargs.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <machine/cpu.h>
#include <machine/reg.h>
/*
* 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
* proc pointer of exec'ing proc
* 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
check_exec(p, epp)
struct proc *p;
struct exec_package *epp;
{
int error, i;
struct vnode *vp;
struct nameidata *ndp;
int resid;
ndp = epp->ep_ndp;
ndp->ni_cnd.cn_nameiop = LOOKUP;
ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME;
/* first get the vnode */
if ((error = namei(ndp)) != 0)
return error;
epp->ep_vp = vp = ndp->ni_vp;
/* check for regular file */
if (vp->v_type != VREG) {
error = EACCES;
goto bad1;
}
/* get attributes */
if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 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) || (p->p_flag & P_TRACED))
epp->ep_vap->va_mode &= ~(VSUID | VSGID);
/* check access. for root we have to see if any exec bit on */
if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
goto bad1;
if ((epp->ep_vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) {
error = EACCES;
goto bad1;
}
/* try to open it */
if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0)
goto bad1;
/* unlock vp, since we don't need it locked from here on out. */
VOP_UNLOCK(vp);
/* 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, p->p_ucred, &resid, p);
if (error)
goto bad2;
epp->ep_hdrvalid = epp->ep_hdrlen - resid;
/*
* set up the vmcmds for creation of the process
* address space
*/
error = ENOEXEC;
for (i = 0; i < nexecs && error != 0; i++) {
int newerror;
if (execsw[i].es_check == NULL)
continue;
newerror = (*execsw[i].es_check)(p, epp);
/* make sure the first "interesting" error code is saved. */
if (!newerror || error == ENOEXEC)
error = newerror;
if (epp->ep_flags & EXEC_DESTR && error != 0)
return error;
}
if (!error) {
/* check that entry point is sane */
if (epp->ep_entry > VM_MAXUSER_ADDRESS)
error = ENOEXEC;
/* check limits */
if ((epp->ep_tsize > MAXTSIZ) ||
(epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur))
error = ENOMEM;
if (!error)
return (0);
}
/*
* free any vmspace-creation commands,
* and release their references
*/
kill_vmcmds(&epp->ep_vmcmds);
bad2:
/*
* unlock and close the vnode, restore the old one, free the
* pathname buf, and punt.
*/
VOP_CLOSE(vp, FREAD, p->p_ucred, p);
vrele(vp);
FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI);
return error;
bad1:
/*
* free the namei pathname buffer, and put the vnode
* (which we don't yet have open).
*/
vput(vp); /* was still locked */
FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI);
return error;
}
/*
* exec system call
*/
/* ARGSUSED */
int
sys_execve(p, v, retval)
register struct proc *p;
void *v;
register_t *retval;
{
register struct sys_execve_args /* {
syscallarg(const char *) path;
syscallarg(char * const *) argp;
syscallarg(char * const *) envp;
} */ *uap = v;
int error, i;
struct exec_package pack;
struct nameidata nid;
struct vattr attr;
struct ucred *cred = p->p_ucred;
char *argp;
char * const *cpp;
char *dp, *sp;
long argc, envc;
size_t len;
char *stack;
struct ps_strings arginfo;
struct vmspace *vm = p->p_vmspace;
char **tmpfap;
int szsigcode;
extern struct emul emul_netbsd;
/*
* figure out the maximum size of an exec header, if necessary.
* XXX should be able to keep LKM code from modifying exec switch
* when we're still using it, but...
*/
if (exec_maxhdrsz == 0) {
for (i = 0; i < nexecs; i++)
if (execsw[i].es_check != NULL
&& execsw[i].es_hdrsz > exec_maxhdrsz)
exec_maxhdrsz = execsw[i].es_hdrsz;
}
/* init the namei data to point the file user's program name */
/* XXX cgd 960926: why do this here? most will be clobbered. */
NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
/*
* initialize the fields of the exec package.
*/
pack.ep_name = SCARG(uap, path);
MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK);
pack.ep_hdrlen = exec_maxhdrsz;
pack.ep_hdrvalid = 0;
pack.ep_ndp = &nid;
pack.ep_emul_arg = NULL;
pack.ep_vmcmds.evs_cnt = 0;
pack.ep_vmcmds.evs_used = 0;
pack.ep_vap = &attr;
pack.ep_emul = &emul_netbsd;
pack.ep_flags = 0;
/* see if we can run it. */
if ((error = check_exec(p, &pack)) != 0)
goto freehdr;
/* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */
/* allocate an argument buffer */
argp = (char *) kmem_alloc_wait(exec_map, NCARGS);
#ifdef DIAGNOSTIC
if (argp == (vm_offset_t) 0)
panic("execve: argp == NULL");
#endif
dp = argp;
argc = 0;
/* copy the fake args list, if there's one, freeing it as we go */
if (pack.ep_flags & EXEC_HASARGL) {
tmpfap = pack.ep_fa;
while (*tmpfap != NULL) {
char *cp;
cp = *tmpfap;
while (*cp)
*dp++ = *cp++;
dp++;
FREE(*tmpfap, M_EXEC);
tmpfap++; argc++;
}
FREE(pack.ep_fa, M_EXEC);
pack.ep_flags &= ~EXEC_HASARGL;
}
/* Now get argv & environment */
if (!(cpp = SCARG(uap, argp))) {
error = EINVAL;
goto bad;
}
if (pack.ep_flags & EXEC_SKIPARG)
cpp++;
while (1) {
len = argp + ARG_MAX - dp;
if ((error = copyin(cpp, &sp, sizeof(sp))) != 0)
goto bad;
if (!sp)
break;
if ((error = copyinstr(sp, dp, len, &len)) != 0) {
if (error == ENAMETOOLONG)
error = E2BIG;
goto bad;
}
dp += len;
cpp++;
argc++;
}
envc = 0;
/* environment need not be there */
if ((cpp = SCARG(uap, envp)) != NULL ) {
while (1) {
len = argp + ARG_MAX - dp;
if ((error = copyin(cpp, &sp, sizeof(sp))) != 0)
goto bad;
if (!sp)
break;
if ((error = copyinstr(sp, dp, len, &len)) != 0) {
if (error == ENAMETOOLONG)
error = E2BIG;
goto bad;
}
dp += len;
cpp++;
envc++;
}
}
dp = (char *) ALIGN(dp);
szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode;
/* Now check if args & environ fit into new stack */
len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) +
sizeof(long) + dp + STACKGAPLEN + szsigcode +
sizeof(struct ps_strings)) - argp;
len = ALIGN(len); /* make the stack "safely" aligned */
if (len > pack.ep_ssize) { /* in effect, compare to initial limit */
error = ENOMEM;
goto bad;
}
/* adjust "active stack depth" for process VSZ */
pack.ep_ssize = len; /* maybe should go elsewhere, but... */
/* Unmap old program */
/* XXX cgd 960926: the sparc #ifdef should be a MD hook */
#ifdef sparc
kill_user_windows(p); /* before stack addresses go away */
#endif
/* Kill shared memory and unmap old program */
#ifdef SYSVSHM
if (vm->vm_shm)
shmexit(p);
#endif
vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS,
VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS);
/* Now map address space */
vm->vm_taddr = (char *) pack.ep_taddr;
vm->vm_tsize = btoc(pack.ep_tsize);
vm->vm_daddr = (char *) pack.ep_daddr;
vm->vm_dsize = btoc(pack.ep_dsize);
vm->vm_ssize = btoc(pack.ep_ssize);
vm->vm_maxsaddr = (char *) pack.ep_maxsaddr;
/* create the new process's VM space by running the vmcmds */
#ifdef DIAGNOSTIC
if (pack.ep_vmcmds.evs_used == 0)
panic("execve: no vmcmds");
#endif
for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) {
struct exec_vmcmd *vcp;
vcp = &pack.ep_vmcmds.evs_cmds[i];
error = (*vcp->ev_proc)(p, vcp);
}
/* free the vmspace-creation commands, and release their references */
kill_vmcmds(&pack.ep_vmcmds);
/* if an error happened, deallocate and punt */
if (error)
goto exec_abort;
/* remember information about the process */
arginfo.ps_nargvstr = argc;
arginfo.ps_nenvstr = envc;
stack = (char *) (USRSTACK - len);
/* Now copy argc, args & environ to new stack */
if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp))
goto exec_abort;
/* copy out the process's ps_strings structure */
if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo)))
goto exec_abort;
/* copy out the process's signal trapoline code */
if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode,
((char *) PS_STRINGS) - szsigcode,
szsigcode))
goto exec_abort;
fdcloseexec(p); /* handle close on exec */
execsigs(p); /* reset catched signals */
/* set command name & other accounting info */
len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN);
bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len);
p->p_comm[len] = 0;
p->p_acflag &= ~AFORK;
/* record proc's vnode, for use by procfs and others */
if (p->p_textvp)
vrele(p->p_textvp);
VREF(pack.ep_vp);
p->p_textvp = pack.ep_vp;
p->p_flag |= P_EXEC;
if (p->p_flag & P_PPWAIT) {
p->p_flag &= ~P_PPWAIT;
wakeup((caddr_t) p->p_pptr);
}
/*
* deal with set[ug]id.
* MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id.
*/
p->p_flag &= ~P_SUGID;
if (((attr.va_mode & VSUID) != 0 && p->p_ucred->cr_uid != attr.va_uid)
|| ((attr.va_mode & VSGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){
p->p_ucred = crcopy(cred);
#ifdef KTRACE
/*
* If process is being ktraced, turn off - unless
* root set it.
*/
if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) {
vrele(p->p_tracep);
p->p_tracep = NULL;
p->p_traceflag = 0;
}
#endif
if (attr.va_mode & VSUID)
p->p_ucred->cr_uid = attr.va_uid;
if (attr.va_mode & VSGID)
p->p_ucred->cr_gid = attr.va_gid;
p->p_flag |= P_SUGID;
}
p->p_cred->p_svuid = p->p_ucred->cr_uid;
p->p_cred->p_svgid = p->p_ucred->cr_gid;
kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS);
FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI);
VOP_CLOSE(pack.ep_vp, FREAD, cred, p);
vrele(pack.ep_vp);
/* setup new registers and do misc. setup. */
(*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack, retval);
if (p->p_flag & P_TRACED)
psignal(p, SIGTRAP);
p->p_emul = pack.ep_emul;
FREE(pack.ep_hdr, M_EXEC);
#ifdef KTRACE
if (KTRPOINT(p, KTR_EMUL))
ktremul(p->p_tracep, p->p_emul->e_name);
#endif
return 0;
bad:
/* free the vmspace-creation commands, and release their references */
kill_vmcmds(&pack.ep_vmcmds);
/* kill any opened file descriptor, if necessary */
if (pack.ep_flags & EXEC_HASFD) {
pack.ep_flags &= ~EXEC_HASFD;
(void) fdrelease(p, pack.ep_fd);
}
/* close and put the exec'd file */
VOP_CLOSE(pack.ep_vp, FREAD, cred, p);
vrele(pack.ep_vp);
FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI);
kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS);
freehdr:
FREE(pack.ep_hdr, M_EXEC);
return error;
exec_abort:
/*
* 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
*/
vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS,
VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS);
if (pack.ep_emul_arg)
FREE(pack.ep_emul_arg, M_TEMP);
FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI);
VOP_CLOSE(pack.ep_vp, FREAD, cred, p);
vrele(pack.ep_vp);
kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS);
FREE(pack.ep_hdr, M_EXEC);
exit1(p, W_EXITCODE(0, SIGABRT));
exit1(p, -1);
/* NOTREACHED */
return 0;
}
void *
copyargs(pack, arginfo, stack, argp)
struct exec_package *pack;
struct ps_strings *arginfo;
void *stack;
void *argp;
{
char **cpp = stack;
char *dp, *sp;
size_t len;
void *nullp = NULL;
int argc = arginfo->ps_nargvstr;
int envc = arginfo->ps_nenvstr;
if (copyout(&argc, cpp++, sizeof(argc)))
return NULL;
dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen);
sp = argp;
/* 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 (copyout(&dp, cpp++, sizeof(dp)) ||
copyoutstr(sp, dp, ARG_MAX, &len))
return NULL;
if (copyout(&nullp, cpp++, sizeof(nullp)))
return NULL;
arginfo->ps_envstr = cpp; /* remember location of envp for later */
for (; --envc >= 0; sp += len, dp += len)
if (copyout(&dp, cpp++, sizeof(dp)) ||
copyoutstr(sp, dp, ARG_MAX, &len))
return NULL;
if (copyout(&nullp, cpp++, sizeof(nullp)))
return NULL;
return cpp;
}
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