xref: /netbsd-src/sys/compat/netbsd32/netbsd32_execve.c (revision 27578b9aac214cc7796ead81dcc5427e79d5f2a0) 
1 /*	$NetBSD: netbsd32_execve.c,v 1.5 2001/07/29 21:28:20 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1998, 2001 Matthew R. Green
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
23  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
25  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
26  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #if defined(_KERNEL_OPT)
32 #include "opt_ktrace.h"
33 #endif
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/malloc.h>
38 #include <sys/mount.h>
39 #include <sys/stat.h>
40 #include <sys/wait.h>
41 #include <sys/ktrace.h>
42 #include <sys/vnode.h>
43 #include <sys/file.h>
44 #include <sys/filedesc.h>
45 #include <sys/namei.h>
46 
47 #include <uvm/uvm_extern.h>
48 
49 #include <sys/syscallargs.h>
50 #include <sys/proc.h>
51 #include <sys/acct.h>
52 #include <sys/exec.h>
53 
54 #include <compat/netbsd32/netbsd32.h>
55 #include <compat/netbsd32/netbsd32_syscall.h>
56 #include <compat/netbsd32/netbsd32_syscallargs.h>
57 
58 /* this is provided by kern/kern_exec.c */
59 extern int exec_maxhdrsz;
60 extern struct lock exec_lock;
61 
62 /*
63  * Need to completly reimplement this syscall due to argument copying.
64  */
65 /* ARGSUSED */
66 int
67 netbsd32_execve(p, v, retval)
68 	struct proc *p;
69 	void *v;
70 	register_t *retval;
71 {
72 	struct netbsd32_execve_args /* {
73 		syscallarg(const netbsd32_charp) path;
74 		syscallarg(netbsd32_charpp) argp;
75 		syscallarg(netbsd32_charpp) envp;
76 	} */ *uap = v;
77 	struct sys_execve_args ua;
78 	caddr_t sg;
79 
80 	NETBSD32TOP_UAP(path, const char);
81 	NETBSD32TOP_UAP(argp, char *);
82 	NETBSD32TOP_UAP(envp, char *);
83 	sg = stackgap_init(p->p_emul);
84 	CHECK_ALT_EXIST(p, &sg, SCARG(&ua, path));
85 
86 	return netbsd32_execve2(p, &ua, retval);
87 }
88 
89 int
90 netbsd32_execve2(p, uap, retval)
91 	struct proc *p;
92 	struct sys_execve_args *uap;
93 	register_t *retval;
94 {
95 	/* Function args */
96 	int error, i;
97 	struct exec_package pack;
98 	struct nameidata nid;
99 	struct vattr attr;
100 	struct ucred *cred = p->p_ucred;
101 	char *argp;
102 	netbsd32_charp const *cpp;
103 	char *dp;
104 	netbsd32_charp sp;
105 	long argc, envc;
106 	size_t len;
107 	char *stack;
108 	struct ps_strings arginfo;
109 	struct vmspace *vm;
110 	char **tmpfap;
111 	int szsigcode;
112 	struct exec_vmcmd *base_vcp = NULL;
113 
114 	/*
115 	 * Init the namei data to point the file user's program name.
116 	 * This is done here rather than in check_exec(), so that it's
117 	 * possible to override this settings if any of makecmd/probe
118 	 * functions call check_exec() recursively - for example,
119 	 * see exec_script_makecmds().
120 	 */
121 	NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
122 
123 	/*
124 	 * initialize the fields of the exec package.
125 	 */
126 	pack.ep_name = SCARG(uap, path);
127 	pack.ep_hdr = malloc(exec_maxhdrsz, M_EXEC, M_WAITOK);
128 	pack.ep_hdrlen = exec_maxhdrsz;
129 	pack.ep_hdrvalid = 0;
130 	pack.ep_ndp = &nid;
131 	pack.ep_emul_arg = NULL;
132 	pack.ep_vmcmds.evs_cnt = 0;
133 	pack.ep_vmcmds.evs_used = 0;
134 	pack.ep_vap = &attr;
135 	pack.ep_flags = 0;
136 
137 	lockmgr(&exec_lock, LK_SHARED, NULL);
138 
139 	/* see if we can run it. */
140 	if ((error = check_exec(p, &pack)) != 0)
141 		goto freehdr;
142 
143 	/* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */
144 
145 	/* allocate an argument buffer */
146 	argp = (char *) uvm_km_valloc_wait(exec_map, NCARGS);
147 #ifdef DIAGNOSTIC
148 	if (argp == (vaddr_t) 0)
149 		panic("netbsd32_execve: argp == NULL");
150 #endif
151 	dp = argp;
152 	argc = 0;
153 
154 	/* copy the fake args list, if there's one, freeing it as we go */
155 	if (pack.ep_flags & EXEC_HASARGL) {
156 		tmpfap = pack.ep_fa;
157 		while (*tmpfap != NULL) {
158 			char *cp;
159 
160 			cp = *tmpfap;
161 			while (*cp)
162 				*dp++ = *cp++;
163 			dp++;
164 
165 			FREE(*tmpfap, M_EXEC);
166 			tmpfap++; argc++;
167 		}
168 		FREE(pack.ep_fa, M_EXEC);
169 		pack.ep_flags &= ~EXEC_HASARGL;
170 	}
171 
172 	/* Now get argv & environment */
173 	if (!(cpp = (netbsd32_charp *)SCARG(uap, argp))) {
174 		error = EINVAL;
175 		goto bad;
176 	}
177 
178 	if (pack.ep_flags & EXEC_SKIPARG)
179 		cpp++;
180 
181 	while (1) {
182 		len = argp + ARG_MAX - dp;
183 		if ((error = copyin(cpp, &sp, sizeof(sp))) != 0)
184 			goto bad;
185 		if (!sp)
186 			break;
187 		if ((error = copyinstr((char *)(u_long)sp, dp,
188 				       len, &len)) != 0) {
189 			if (error == ENAMETOOLONG)
190 				error = E2BIG;
191 			goto bad;
192 		}
193 		dp += len;
194 		cpp++;
195 		argc++;
196 	}
197 
198 	envc = 0;
199 	/* environment need not be there */
200 	if ((cpp = (netbsd32_charp *)SCARG(uap, envp)) != NULL ) {
201 		while (1) {
202 			len = argp + ARG_MAX - dp;
203 			if ((error = copyin(cpp, &sp, sizeof(sp))) != 0)
204 				goto bad;
205 			if (!sp)
206 				break;
207 			if ((error = copyinstr((char *)(u_long)sp,
208 					       dp, len, &len)) != 0) {
209 				if (error == ENAMETOOLONG)
210 					error = E2BIG;
211 				goto bad;
212 			}
213 			dp += len;
214 			cpp++;
215 			envc++;
216 		}
217 	}
218 
219 	dp = (char *) ALIGN(dp);
220 
221 	szsigcode = pack.ep_es->es_emul->e_esigcode -
222 	    pack.ep_es->es_emul->e_sigcode;
223 
224 	/* Now check if args & environ fit into new stack */
225 	if (pack.ep_flags & EXEC_32)
226 		len = ((argc + envc + 2 + pack.ep_es->es_arglen) *
227 		    sizeof(int) + sizeof(int) + dp + STACKGAPLEN +
228 		    szsigcode + sizeof(struct ps_strings)) - argp;
229 	else
230 		len = ((argc + envc + 2 + pack.ep_es->es_arglen) *
231 		    sizeof(char *) + sizeof(int) + dp + STACKGAPLEN +
232 		    szsigcode + sizeof(struct ps_strings)) - argp;
233 
234 	len = ALIGN(len);	/* make the stack "safely" aligned */
235 
236 	if (len > pack.ep_ssize) { /* in effect, compare to initial limit */
237 		error = ENOMEM;
238 		goto bad;
239 	}
240 
241 	/* adjust "active stack depth" for process VSZ */
242 	pack.ep_ssize = len;	/* maybe should go elsewhere, but... */
243 
244 	/*
245 	 * Do whatever is necessary to prepare the address space
246 	 * for remapping.  Note that this might replace the current
247 	 * vmspace with another!
248 	 */
249 	uvmspace_exec(p, VM_MIN_ADDRESS, (vaddr_t)pack.ep_minsaddr);
250 
251 	/* Now map address space */
252 	vm = p->p_vmspace;
253 	vm->vm_taddr = (char *) pack.ep_taddr;
254 	vm->vm_tsize = btoc(pack.ep_tsize);
255 	vm->vm_daddr = (char *) pack.ep_daddr;
256 	vm->vm_dsize = btoc(pack.ep_dsize);
257 	vm->vm_ssize = btoc(pack.ep_ssize);
258 	vm->vm_maxsaddr = (char *) pack.ep_maxsaddr;
259 	vm->vm_minsaddr = (char *) pack.ep_minsaddr;
260 
261 	/* create the new process's VM space by running the vmcmds */
262 #ifdef DIAGNOSTIC
263 	if (pack.ep_vmcmds.evs_used == 0)
264 		panic("netbsd32_execve: no vmcmds");
265 #endif
266 	for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) {
267 		struct exec_vmcmd *vcp;
268 
269 		vcp = &pack.ep_vmcmds.evs_cmds[i];
270 		if (vcp->ev_flags & VMCMD_RELATIVE) {
271 #ifdef DIAGNOSTIC
272 			if (base_vcp == NULL)
273 				panic("netbsd32_execve: relative vmcmd with no base");
274 			if (vcp->ev_flags & VMCMD_BASE)
275 				panic("netbsd32_execve: illegal base & relative vmcmd");
276 #endif
277 			vcp->ev_addr += base_vcp->ev_addr;
278 		}
279 		error = (*vcp->ev_proc)(p, vcp);
280 #ifdef DEBUG
281 		if (error) {
282 			int j;
283 
284 			for (j = 0; j <= i; j++)
285 				printf("vmcmd[%d] = %#lx/%#lx @ %#lx\n", j,
286 				       vcp[j-i].ev_addr, vcp[j-i].ev_len,
287 				       vcp[j-i].ev_offset);
288 		}
289 #endif
290 		if (vcp->ev_flags & VMCMD_BASE)
291 			base_vcp = vcp;
292 	}
293 
294 	/* free the vmspace-creation commands, and release their references */
295 	kill_vmcmds(&pack.ep_vmcmds);
296 
297 	/* if an error happened, deallocate and punt */
298 	if (error) {
299 #ifdef DEBUG
300 		printf("netbsd32_execve: vmcmd %i failed: %d\n", i-1, error);
301 #endif
302 		goto exec_abort;
303 	}
304 
305 	/* remember information about the process */
306 	arginfo.ps_nargvstr = argc;
307 	arginfo.ps_nenvstr = envc;
308 
309 	stack = (char *) (vm->vm_minsaddr - len);
310 	/* Now copy argc, args & environ to new stack */
311 	error = (*pack.ep_es->es_copyargs)(&pack, &arginfo,
312 	    &stack, argp);
313 	if (error) {
314 #ifdef DEBUG
315 		printf("netbsd32_execve: copyargs failed\n");
316 #endif
317 		goto exec_abort;
318 	}
319 	/* restore the stack back to its original point */
320 	stack = (char *) (vm->vm_minsaddr - len);
321 
322 	/* fill process ps_strings info */
323 	p->p_psstr = (struct ps_strings *)(stack - sizeof(struct ps_strings));
324 	p->p_psargv = offsetof(struct ps_strings, ps_argvstr);
325 	p->p_psnargv = offsetof(struct ps_strings, ps_nargvstr);
326 	p->p_psenv = offsetof(struct ps_strings, ps_envstr);
327 	p->p_psnenv = offsetof(struct ps_strings, ps_nenvstr);
328 
329 	/* copy out the process's ps_strings structure */
330 	if (copyout(&arginfo, (char *)p->p_psstr, sizeof(arginfo))) {
331 #ifdef DEBUG
332 		printf("netbsd32_execve: ps_strings copyout failed\n");
333 #endif
334 		goto exec_abort;
335 	}
336 
337 	/* copy out the process's signal trapoline code */
338 	if (szsigcode) {
339 		if (copyout((char *)pack.ep_es->es_emul->e_sigcode,
340 		    p->p_sigctx.ps_sigcode = (char *)p->p_psstr - szsigcode,
341 		    szsigcode)) {
342 #ifdef DEBUG
343 			printf("netbsd32_execve: sig trampoline copyout failed\n");
344 #endif
345 			goto exec_abort;
346 		}
347 #ifdef PMAP_NEED_PROCWR
348 		/* This is code. Let the pmap do what is needed. */
349 		pmap_procwr(p, (vaddr_t)p->p_sigacts->ps_sigcode, szsigcode);
350 #endif
351 	}
352 
353 	stopprofclock(p);	/* stop profiling */
354 	fdcloseexec(p);		/* handle close on exec */
355 	execsigs(p);		/* reset catched signals */
356 	p->p_ctxlink = NULL;	/* reset ucontext link */
357 
358 	/* set command name & other accounting info */
359 	len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN);
360 	memcpy(p->p_comm, nid.ni_cnd.cn_nameptr, len);
361 	p->p_comm[len] = 0;
362 	p->p_acflag &= ~AFORK;
363 
364 	/* record proc's vnode, for use by procfs and others */
365         if (p->p_textvp)
366                 vrele(p->p_textvp);
367 	VREF(pack.ep_vp);
368 	p->p_textvp = pack.ep_vp;
369 
370 	p->p_flag |= P_EXEC;
371 	if (p->p_flag & P_PPWAIT) {
372 		p->p_flag &= ~P_PPWAIT;
373 		wakeup((caddr_t) p->p_pptr);
374 	}
375 
376 	/*
377 	 * deal with set[ug]id.
378 	 * MNT_NOSUID has already been used to disable s[ug]id.
379 	 */
380 	if ((p->p_flag & P_TRACED) == 0 &&
381 
382 	    (((attr.va_mode & S_ISUID) != 0 &&
383 	      p->p_ucred->cr_uid != attr.va_uid) ||
384 
385 	     ((attr.va_mode & S_ISGID) != 0 &&
386 	      p->p_ucred->cr_gid != attr.va_gid))) {
387 		/*
388 		 * Mark the process as SUGID before we do
389 		 * anything that might block.
390 		 */
391 		p_sugid(p);
392 
393 		p->p_ucred = crcopy(cred);
394 #ifdef KTRACE
395 		/*
396 		 * If process is being ktraced, turn off - unless
397 		 * root set it.
398 		 */
399 		if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT))
400 			ktrderef(p);
401 #endif
402 		if (attr.va_mode & S_ISUID)
403 			p->p_ucred->cr_uid = attr.va_uid;
404 		if (attr.va_mode & S_ISGID)
405 			p->p_ucred->cr_gid = attr.va_gid;
406 	} else
407 		p->p_flag &= ~P_SUGID;
408 	p->p_cred->p_svuid = p->p_ucred->cr_uid;
409 	p->p_cred->p_svgid = p->p_ucred->cr_gid;
410 
411 	doexechooks(p);
412 
413 	uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS);
414 
415 	PNBUF_PUT(nid.ni_cnd.cn_pnbuf);
416 	vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY);
417 	VOP_CLOSE(pack.ep_vp, FREAD, cred, p);
418 	vput(pack.ep_vp);
419 
420 	/* setup new registers and do misc. setup. */
421 	(*pack.ep_es->es_setregs)(p, &pack, (u_long) stack);
422 
423 	if (p->p_flag & P_TRACED)
424 		psignal(p, SIGTRAP);
425 
426 	free(pack.ep_hdr, M_EXEC);
427 
428 	/*
429 	 * Call emulation specific exec hook. This can setup setup per-process
430 	 * p->p_emuldata or do any other per-process stuff an emulation needs.
431 	 *
432 	 * If we are executing process of different emulation than the
433 	 * original forked process, call e_proc_exit() of the old emulation
434 	 * first, then e_proc_exec() of new emulation. If the emulation is
435 	 * same, the exec hook code should deallocate any old emulation
436 	 * resources held previously by this process.
437 	 */
438 	if (p->p_emul && p->p_emul->e_proc_exit
439 	    && p->p_emul != pack.ep_es->es_emul)
440 		(*p->p_emul->e_proc_exit)(p);
441 
442 	/*
443 	 * Call exec hook. Emulation code may NOT store reference to anything
444 	 * from &pack.
445 	 */
446         if (pack.ep_es->es_emul->e_proc_exec)
447                 (*pack.ep_es->es_emul->e_proc_exec)(p, &pack);
448 
449 	/* update p_emul, the old value is no longer needed */
450 	p->p_emul = pack.ep_es->es_emul;
451 
452 #ifdef KTRACE
453 	if (KTRPOINT(p, KTR_EMUL))
454 		ktremul(p);
455 #endif
456 
457 	lockmgr(&exec_lock, LK_RELEASE, NULL);
458 
459 	return (EJUSTRETURN);
460 
461 bad:
462 	/* free the vmspace-creation commands, and release their references */
463 	kill_vmcmds(&pack.ep_vmcmds);
464 	/* kill any opened file descriptor, if necessary */
465 	if (pack.ep_flags & EXEC_HASFD) {
466 		pack.ep_flags &= ~EXEC_HASFD;
467 		(void) fdrelease(p, pack.ep_fd);
468 	}
469 	/* close and put the exec'd file */
470 	vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY);
471 	VOP_CLOSE(pack.ep_vp, FREAD, cred, p);
472 	vput(pack.ep_vp);
473 	PNBUF_PUT(nid.ni_cnd.cn_pnbuf);
474 	uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS);
475 
476 freehdr:
477 	lockmgr(&exec_lock, LK_RELEASE, NULL);
478 
479 	free(pack.ep_hdr, M_EXEC);
480 	return error;
481 
482 exec_abort:
483 	lockmgr(&exec_lock, LK_RELEASE, NULL);
484 
485 	/*
486 	 * the old process doesn't exist anymore.  exit gracefully.
487 	 * get rid of the (new) address space we have created, if any, get rid
488 	 * of our namei data and vnode, and exit noting failure
489 	 */
490 	uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS,
491 		VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS);
492 	if (pack.ep_emul_arg)
493 		FREE(pack.ep_emul_arg, M_TEMP);
494 	PNBUF_PUT(nid.ni_cnd.cn_pnbuf);
495 	vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY);
496 	VOP_CLOSE(pack.ep_vp, FREAD, cred, p);
497 	vput(pack.ep_vp);
498 	uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS);
499 	free(pack.ep_hdr, M_EXEC);
500 	exit1(p, W_EXITCODE(error, SIGABRT));
501 
502 	/* NOTREACHED */
503 	return 0;
504 }
505