xref: /freebsd/sys/kern/imgact_aout.c (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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_transtrap	= NULL,
80 	.sv_fixup	= aout_fixup,
81 	.sv_sendsig	= sendsig,
82 	.sv_sigcode	= sigcode,
83 	.sv_szsigcode	= &szsigcode,
84 	.sv_name	= "FreeBSD a.out",
85 	.sv_coredump	= NULL,
86 	.sv_imgact_try	= NULL,
87 	.sv_minsigstksz	= MINSIGSTKSZ,
88 	.sv_minuser	= VM_MIN_ADDRESS,
89 	.sv_maxuser	= AOUT32_USRSTACK,
90 	.sv_usrstack	= AOUT32_USRSTACK,
91 	.sv_psstrings	= AOUT32_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 };
105 
106 #elif defined(__amd64__)
107 
108 #define	AOUT32_PS_STRINGS \
109     (AOUT32_USRSTACK - sizeof(struct freebsd32_ps_strings))
110 #define	AOUT32_MINUSER		FREEBSD32_MINUSER
111 
112 extern const char *freebsd32_syscallnames[];
113 extern u_long ia32_maxssiz;
114 
115 struct sysentvec aout_sysvec = {
116 	.sv_size	= FREEBSD32_SYS_MAXSYSCALL,
117 	.sv_table	= freebsd32_sysent,
118 	.sv_transtrap	= NULL,
119 	.sv_fixup	= aout_fixup,
120 	.sv_sendsig	= ia32_sendsig,
121 	.sv_sigcode	= ia32_sigcode,
122 	.sv_szsigcode	= &sz_ia32_sigcode,
123 	.sv_name	= "FreeBSD a.out",
124 	.sv_coredump	= NULL,
125 	.sv_imgact_try	= NULL,
126 	.sv_minsigstksz	= MINSIGSTKSZ,
127 	.sv_minuser	= AOUT32_MINUSER,
128 	.sv_maxuser	= AOUT32_USRSTACK,
129 	.sv_usrstack	= AOUT32_USRSTACK,
130 	.sv_psstrings	= AOUT32_PS_STRINGS,
131 	.sv_stackprot	= VM_PROT_ALL,
132 	.sv_copyout_strings	= freebsd32_copyout_strings,
133 	.sv_setregs	= ia32_setregs,
134 	.sv_fixlimit	= ia32_fixlimit,
135 	.sv_maxssiz	= &ia32_maxssiz,
136 	.sv_flags	= SV_ABI_FREEBSD | SV_AOUT | SV_IA32 | SV_ILP32,
137 	.sv_set_syscall_retval = ia32_set_syscall_retval,
138 	.sv_fetch_syscall_args = ia32_fetch_syscall_args,
139 	.sv_syscallnames = freebsd32_syscallnames,
140 };
141 #else
142 #error "Port me"
143 #endif
144 
145 static int
146 aout_fixup(uintptr_t *stack_base, struct image_params *imgp)
147 {
148 
149 	*stack_base -= sizeof(uint32_t);
150 	if (suword32((void *)*stack_base, imgp->args->argc) != 0)
151 		return (EFAULT);
152 	return (0);
153 }
154 
155 static int
156 exec_aout_imgact(struct image_params *imgp)
157 {
158 	const struct exec *a_out = (const struct exec *) imgp->image_header;
159 	struct vmspace *vmspace;
160 	vm_map_t map;
161 	vm_object_t object;
162 	vm_offset_t text_end, data_end;
163 	unsigned long virtual_offset;
164 	unsigned long file_offset;
165 	unsigned long bss_size;
166 	int error;
167 
168 	/*
169 	 * Linux and *BSD binaries look very much alike,
170 	 * only the machine id is different:
171 	 * 0x64 for Linux, 0x86 for *BSD, 0x00 for BSDI.
172 	 * NetBSD is in network byte order.. ugh.
173 	 */
174 	if (((a_out->a_midmag >> 16) & 0xff) != 0x86 &&
175 	    ((a_out->a_midmag >> 16) & 0xff) != 0 &&
176 	    ((((int)ntohl(a_out->a_midmag)) >> 16) & 0xff) != 0x86)
177                 return -1;
178 
179 	/*
180 	 * Set file/virtual offset based on a.out variant.
181 	 *	We do two cases: host byte order and network byte order
182 	 *	(for NetBSD compatibility)
183 	 */
184 	switch ((int)(a_out->a_midmag & 0xffff)) {
185 	case ZMAGIC:
186 		virtual_offset = 0;
187 		if (a_out->a_text) {
188 			file_offset = PAGE_SIZE;
189 		} else {
190 			/* Bill's "screwball mode" */
191 			file_offset = 0;
192 		}
193 		break;
194 	case QMAGIC:
195 		virtual_offset = PAGE_SIZE;
196 		file_offset = 0;
197 		/* Pass PS_STRINGS for BSD/OS binaries only. */
198 		if (N_GETMID(*a_out) == MID_ZERO)
199 			imgp->ps_strings = (void *)aout_sysvec.sv_psstrings;
200 		break;
201 	default:
202 		/* NetBSD compatibility */
203 		switch ((int)(ntohl(a_out->a_midmag) & 0xffff)) {
204 		case ZMAGIC:
205 		case QMAGIC:
206 			virtual_offset = PAGE_SIZE;
207 			file_offset = 0;
208 			break;
209 		default:
210 			return (-1);
211 		}
212 	}
213 
214 	bss_size = roundup(a_out->a_bss, PAGE_SIZE);
215 
216 	/*
217 	 * Check various fields in header for validity/bounds.
218 	 */
219 	if (/* entry point must lay with text region */
220 	    a_out->a_entry < virtual_offset ||
221 	    a_out->a_entry >= virtual_offset + a_out->a_text ||
222 
223 	    /* text and data size must each be page rounded */
224 	    a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK
225 
226 #ifdef __amd64__
227 	    ||
228 	    /* overflows */
229 	    virtual_offset + a_out->a_text + a_out->a_data + bss_size > UINT_MAX
230 #endif
231 	    )
232 		return (-1);
233 
234 	/* text + data can't exceed file size */
235 	if (a_out->a_data + a_out->a_text > imgp->attr->va_size)
236 		return (EFAULT);
237 
238 	/*
239 	 * text/data/bss must not exceed limits
240 	 */
241 	PROC_LOCK(imgp->proc);
242 	if (/* text can't exceed maximum text size */
243 	    a_out->a_text > maxtsiz ||
244 
245 	    /* data + bss can't exceed rlimit */
246 	    a_out->a_data + bss_size > lim_cur_proc(imgp->proc, RLIMIT_DATA) ||
247 	    racct_set(imgp->proc, RACCT_DATA, a_out->a_data + bss_size) != 0) {
248 		PROC_UNLOCK(imgp->proc);
249 		return (ENOMEM);
250 	}
251 	PROC_UNLOCK(imgp->proc);
252 
253 	/*
254 	 * Avoid a possible deadlock if the current address space is destroyed
255 	 * and that address space maps the locked vnode.  In the common case,
256 	 * the locked vnode's v_usecount is decremented but remains greater
257 	 * than zero.  Consequently, the vnode lock is not needed by vrele().
258 	 * However, in cases where the vnode lock is external, such as nullfs,
259 	 * v_usecount may become zero.
260 	 */
261 	VOP_UNLOCK(imgp->vp);
262 
263 	/*
264 	 * Destroy old process VM and create a new one (with a new stack)
265 	 */
266 	error = exec_new_vmspace(imgp, &aout_sysvec);
267 
268 	vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
269 	if (error)
270 		return (error);
271 
272 	/*
273 	 * The vm space can be changed by exec_new_vmspace
274 	 */
275 	vmspace = imgp->proc->p_vmspace;
276 
277 	object = imgp->object;
278 	map = &vmspace->vm_map;
279 	vm_map_lock(map);
280 	vm_object_reference(object);
281 
282 	text_end = virtual_offset + a_out->a_text;
283 	error = vm_map_insert(map, object,
284 		file_offset,
285 		virtual_offset, text_end,
286 		VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
287 		MAP_COPY_ON_WRITE | MAP_PREFAULT | MAP_VN_EXEC);
288 	if (error) {
289 		vm_map_unlock(map);
290 		vm_object_deallocate(object);
291 		return (error);
292 	}
293 	VOP_SET_TEXT_CHECKED(imgp->vp);
294 	data_end = text_end + a_out->a_data;
295 	if (a_out->a_data) {
296 		vm_object_reference(object);
297 		error = vm_map_insert(map, object,
298 			file_offset + a_out->a_text,
299 			text_end, data_end,
300 			VM_PROT_ALL, VM_PROT_ALL,
301 			MAP_COPY_ON_WRITE | MAP_PREFAULT | MAP_VN_EXEC);
302 		if (error) {
303 			vm_map_unlock(map);
304 			vm_object_deallocate(object);
305 			return (error);
306 		}
307 		VOP_SET_TEXT_CHECKED(imgp->vp);
308 	}
309 
310 	if (bss_size) {
311 		error = vm_map_insert(map, NULL, 0,
312 			data_end, data_end + bss_size,
313 			VM_PROT_ALL, VM_PROT_ALL, 0);
314 		if (error) {
315 			vm_map_unlock(map);
316 			return (error);
317 		}
318 	}
319 	vm_map_unlock(map);
320 
321 	/* Fill in process VM information */
322 	vmspace->vm_tsize = a_out->a_text >> PAGE_SHIFT;
323 	vmspace->vm_dsize = (a_out->a_data + bss_size) >> PAGE_SHIFT;
324 	vmspace->vm_taddr = (caddr_t) (uintptr_t) virtual_offset;
325 	vmspace->vm_daddr = (caddr_t) (uintptr_t)
326 			    (virtual_offset + a_out->a_text);
327 
328 	/* Fill in image_params */
329 	imgp->interpreted = 0;
330 	imgp->entry_addr = a_out->a_entry;
331 
332 	imgp->proc->p_sysent = &aout_sysvec;
333 
334 	return (0);
335 }
336 
337 /*
338  * Tell kern_execve.c about it, with a little help from the linker.
339  */
340 static struct execsw aout_execsw = {
341 	.ex_imgact = exec_aout_imgact,
342 	.ex_name = "a.out"
343 };
344 EXEC_SET(aout, aout_execsw);
345