xref: /freebsd/sys/kern/imgact_aout.c (revision ccb59683b98360afaf5b5bb641a68fea22c68d0b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1993, David Greenman
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  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/exec.h>
34 #include <sys/imgact.h>
35 #include <sys/imgact_aout.h>
36 #include <sys/kernel.h>
37 #include <sys/limits.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/proc.h>
42 #include <sys/racct.h>
43 #include <sys/resourcevar.h>
44 #include <sys/signalvar.h>
45 #include <sys/syscall.h>
46 #include <sys/sysent.h>
47 #include <sys/systm.h>
48 #include <sys/vnode.h>
49 
50 #include <machine/frame.h>
51 #include <machine/md_var.h>
52 
53 #include <vm/vm.h>
54 #include <vm/pmap.h>
55 #include <vm/vm_map.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_param.h>
58 
59 #ifdef __amd64__
60 #include <compat/freebsd32/freebsd32_signal.h>
61 #include <compat/freebsd32/freebsd32_util.h>
62 #include <compat/freebsd32/freebsd32_proto.h>
63 #include <compat/freebsd32/freebsd32_syscall.h>
64 #include <compat/ia32/ia32_signal.h>
65 #endif
66 
67 static int	exec_aout_imgact(struct image_params *imgp);
68 static int	aout_fixup(uintptr_t *stack_base, struct image_params *imgp);
69 
70 #define	AOUT32_USRSTACK		0xbfc00000
71 
72 #if defined(__i386__)
73 
74 #define	AOUT32_PS_STRINGS	(AOUT32_USRSTACK - sizeof(struct ps_strings))
75 
76 struct sysentvec aout_sysvec = {
77 	.sv_size	= SYS_MAXSYSCALL,
78 	.sv_table	= sysent,
79 	.sv_fixup	= aout_fixup,
80 	.sv_sendsig	= sendsig,
81 	.sv_sigcode	= sigcode,
82 	.sv_szsigcode	= &szsigcode,
83 	.sv_name	= "FreeBSD a.out",
84 	.sv_coredump	= NULL,
85 	.sv_imgact_try	= NULL,
86 	.sv_minsigstksz	= MINSIGSTKSZ,
87 	.sv_minuser	= VM_MIN_ADDRESS,
88 	.sv_maxuser	= AOUT32_USRSTACK,
89 	.sv_usrstack	= AOUT32_USRSTACK,
90 	.sv_psstrings	= AOUT32_PS_STRINGS,
91 	.sv_psstringssz	= sizeof(struct ps_strings),
92 	.sv_stackprot	= VM_PROT_ALL,
93 	.sv_copyout_strings	= exec_copyout_strings,
94 	.sv_setregs	= exec_setregs,
95 	.sv_fixlimit	= NULL,
96 	.sv_maxssiz	= NULL,
97 	.sv_flags	= SV_ABI_FREEBSD | SV_AOUT | SV_IA32 | SV_ILP32,
98 	.sv_set_syscall_retval = cpu_set_syscall_retval,
99 	.sv_fetch_syscall_args = cpu_fetch_syscall_args,
100 	.sv_syscallnames = syscallnames,
101 	.sv_schedtail	= NULL,
102 	.sv_thread_detach = NULL,
103 	.sv_trap	= NULL,
104 	.sv_onexec_old = exec_onexec_old,
105 	.sv_onexit =  exit_onexit,
106 	.sv_set_fork_retval = x86_set_fork_retval,
107 };
108 
109 #elif defined(__amd64__)
110 
111 #include "vdso_ia32_offsets.h"
112 
113 extern const char _binary_elf_vdso32_so_1_start[];
114 extern const char _binary_elf_vdso32_so_1_end[];
115 extern char _binary_elf_vdso32_so_1_size;
116 
117 #define	AOUT32_PS_STRINGS \
118     (AOUT32_USRSTACK - sizeof(struct freebsd32_ps_strings))
119 #define	AOUT32_MINUSER		FREEBSD32_MINUSER
120 
121 extern const char *freebsd32_syscallnames[];
122 extern u_long ia32_maxssiz;
123 
124 static int aout_szsigcode;
125 
126 struct sysentvec aout_sysvec = {
127 	.sv_size	= FREEBSD32_SYS_MAXSYSCALL,
128 	.sv_table	= freebsd32_sysent,
129 	.sv_fixup	= aout_fixup,
130 	.sv_sendsig	= ia32_sendsig,
131 	.sv_sigcode	= _binary_elf_vdso32_so_1_start,
132 	.sv_szsigcode	= &aout_szsigcode,
133 	.sv_name	= "FreeBSD a.out",
134 	.sv_coredump	= NULL,
135 	.sv_imgact_try	= NULL,
136 	.sv_minsigstksz	= MINSIGSTKSZ,
137 	.sv_minuser	= AOUT32_MINUSER,
138 	.sv_maxuser	= AOUT32_USRSTACK,
139 	.sv_usrstack	= AOUT32_USRSTACK,
140 	.sv_psstrings	= AOUT32_PS_STRINGS,
141 	.sv_psstringssz	= sizeof(struct freebsd32_ps_strings),
142 	.sv_stackprot	= VM_PROT_ALL,
143 	.sv_copyout_strings	= freebsd32_copyout_strings,
144 	.sv_setregs	= ia32_setregs,
145 	.sv_fixlimit	= ia32_fixlimit,
146 	.sv_maxssiz	= &ia32_maxssiz,
147 	.sv_flags	= SV_ABI_FREEBSD | SV_AOUT | SV_IA32 | SV_ILP32,
148 	.sv_set_syscall_retval = ia32_set_syscall_retval,
149 	.sv_fetch_syscall_args = ia32_fetch_syscall_args,
150 	.sv_syscallnames = freebsd32_syscallnames,
151 	.sv_onexec_old	= exec_onexec_old,
152 	.sv_onexit	= exit_onexit,
153 	.sv_set_fork_retval = x86_set_fork_retval,
154 };
155 
156 static void
157 aout_sysent(void *arg __unused)
158 {
159 	aout_szsigcode = (int)(uintptr_t)&_binary_elf_vdso32_so_1_size;
160 }
161 SYSINIT(aout_sysent, SI_SUB_EXEC, SI_ORDER_ANY, aout_sysent, NULL);
162 #else
163 #error "Only ia32 arch is supported"
164 #endif
165 
166 static int
167 aout_fixup(uintptr_t *stack_base, struct image_params *imgp)
168 {
169 
170 	*stack_base -= sizeof(uint32_t);
171 	if (suword32((void *)*stack_base, imgp->args->argc) != 0)
172 		return (EFAULT);
173 	return (0);
174 }
175 
176 static int
177 exec_aout_imgact(struct image_params *imgp)
178 {
179 	const struct exec *a_out;
180 	struct vmspace *vmspace;
181 	vm_map_t map;
182 	vm_object_t object;
183 	vm_offset_t text_end, data_end;
184 	unsigned long virtual_offset;
185 	unsigned long file_offset;
186 	unsigned long bss_size;
187 	int error;
188 
189 	a_out = (const struct exec *)imgp->image_header;
190 
191 	/*
192 	 * Linux and *BSD binaries look very much alike,
193 	 * only the machine id is different:
194 	 * 0x64 for Linux, 0x86 for *BSD, 0x00 for BSDI.
195 	 * NetBSD is in network byte order.. ugh.
196 	 */
197 	if (((a_out->a_midmag >> 16) & 0xff) != 0x86 &&
198 	    ((a_out->a_midmag >> 16) & 0xff) != 0 &&
199 	    ((((int)ntohl(a_out->a_midmag)) >> 16) & 0xff) != 0x86)
200                 return (-1);
201 
202 	/*
203 	 * Set file/virtual offset based on a.out variant.
204 	 *	We do two cases: host byte order and network byte order
205 	 *	(for NetBSD compatibility)
206 	 */
207 	switch ((int)(a_out->a_midmag & 0xffff)) {
208 	case ZMAGIC:
209 		virtual_offset = 0;
210 		if (a_out->a_text) {
211 			file_offset = PAGE_SIZE;
212 		} else {
213 			/* Bill's "screwball mode" */
214 			file_offset = 0;
215 		}
216 		break;
217 	case QMAGIC:
218 		virtual_offset = PAGE_SIZE;
219 		file_offset = 0;
220 		/* Pass PS_STRINGS for BSD/OS binaries only. */
221 		if (N_GETMID(*a_out) == MID_ZERO)
222 			imgp->ps_strings = (void *)aout_sysvec.sv_psstrings;
223 		break;
224 	default:
225 		/* NetBSD compatibility */
226 		switch ((int)(ntohl(a_out->a_midmag) & 0xffff)) {
227 		case ZMAGIC:
228 		case QMAGIC:
229 			virtual_offset = PAGE_SIZE;
230 			file_offset = 0;
231 			break;
232 		default:
233 			return (-1);
234 		}
235 	}
236 
237 	bss_size = roundup(a_out->a_bss, PAGE_SIZE);
238 
239 	/*
240 	 * Check various fields in header for validity/bounds.
241 	 */
242 	if (/* entry point must lay with text region */
243 	    a_out->a_entry < virtual_offset ||
244 	    a_out->a_entry >= virtual_offset + a_out->a_text ||
245 
246 	    /* text and data size must each be page rounded */
247 	    a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK
248 
249 #ifdef __amd64__
250 	    ||
251 	    /* overflows */
252 	    virtual_offset + a_out->a_text + a_out->a_data + bss_size > UINT_MAX
253 #endif
254 	    )
255 		return (-1);
256 
257 	/* text + data can't exceed file size */
258 	if (a_out->a_data + a_out->a_text > imgp->attr->va_size)
259 		return (EFAULT);
260 
261 	/*
262 	 * text/data/bss must not exceed limits
263 	 */
264 	PROC_LOCK(imgp->proc);
265 	if (/* text can't exceed maximum text size */
266 	    a_out->a_text > maxtsiz ||
267 
268 	    /* data + bss can't exceed rlimit */
269 	    a_out->a_data + bss_size > lim_cur_proc(imgp->proc, RLIMIT_DATA) ||
270 	    racct_set(imgp->proc, RACCT_DATA, a_out->a_data + bss_size) != 0) {
271 		PROC_UNLOCK(imgp->proc);
272 		return (ENOMEM);
273 	}
274 	PROC_UNLOCK(imgp->proc);
275 
276 	/*
277 	 * Avoid a possible deadlock if the current address space is destroyed
278 	 * and that address space maps the locked vnode.  In the common case,
279 	 * the locked vnode's v_usecount is decremented but remains greater
280 	 * than zero.  Consequently, the vnode lock is not needed by vrele().
281 	 * However, in cases where the vnode lock is external, such as nullfs,
282 	 * v_usecount may become zero.
283 	 */
284 	VOP_UNLOCK(imgp->vp);
285 
286 	/*
287 	 * Destroy old process VM and create a new one (with a new stack)
288 	 */
289 	error = exec_new_vmspace(imgp, &aout_sysvec);
290 
291 	vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
292 	if (error)
293 		return (error);
294 
295 	/*
296 	 * The vm space can be changed by exec_new_vmspace
297 	 */
298 	vmspace = imgp->proc->p_vmspace;
299 
300 	object = imgp->object;
301 	map = &vmspace->vm_map;
302 	vm_map_lock(map);
303 	vm_object_reference(object);
304 
305 	text_end = virtual_offset + a_out->a_text;
306 	error = vm_map_insert(map, object,
307 		file_offset,
308 		virtual_offset, text_end,
309 		VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
310 		MAP_COPY_ON_WRITE | MAP_PREFAULT | MAP_VN_EXEC);
311 	if (error) {
312 		vm_map_unlock(map);
313 		vm_object_deallocate(object);
314 		return (error);
315 	}
316 	VOP_SET_TEXT_CHECKED(imgp->vp);
317 	data_end = text_end + a_out->a_data;
318 	if (a_out->a_data) {
319 		vm_object_reference(object);
320 		error = vm_map_insert(map, object,
321 			file_offset + a_out->a_text,
322 			text_end, data_end,
323 			VM_PROT_ALL, VM_PROT_ALL,
324 			MAP_COPY_ON_WRITE | MAP_PREFAULT | MAP_VN_EXEC);
325 		if (error) {
326 			vm_map_unlock(map);
327 			vm_object_deallocate(object);
328 			return (error);
329 		}
330 		VOP_SET_TEXT_CHECKED(imgp->vp);
331 	}
332 
333 	if (bss_size) {
334 		error = vm_map_insert(map, NULL, 0,
335 			data_end, data_end + bss_size,
336 			VM_PROT_ALL, VM_PROT_ALL, 0);
337 		if (error) {
338 			vm_map_unlock(map);
339 			return (error);
340 		}
341 	}
342 	vm_map_unlock(map);
343 
344 	/* Fill in process VM information */
345 	vmspace->vm_tsize = a_out->a_text >> PAGE_SHIFT;
346 	vmspace->vm_dsize = (a_out->a_data + bss_size) >> PAGE_SHIFT;
347 	vmspace->vm_taddr = (caddr_t) (uintptr_t) virtual_offset;
348 	vmspace->vm_daddr = (caddr_t) (uintptr_t)
349 			    (virtual_offset + a_out->a_text);
350 
351 	error = exec_map_stack(imgp);
352 	if (error != 0)
353 		return (error);
354 
355 	/* Fill in image_params */
356 	imgp->interpreted = 0;
357 	imgp->entry_addr = a_out->a_entry;
358 
359 	imgp->proc->p_sysent = &aout_sysvec;
360 
361 	return (0);
362 }
363 
364 /*
365  * Tell kern_execve.c about it, with a little help from the linker.
366  */
367 static struct execsw aout_execsw = {
368 	.ex_imgact = exec_aout_imgact,
369 	.ex_name = "a.out"
370 };
371 EXEC_SET(aout, aout_execsw);
372