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 .sv_onexec_old = exec_onexec_old,
105 .sv_onexit = exit_onexit,
106 };
107
108 #elif defined(__amd64__)
109
110 #define AOUT32_PS_STRINGS \
111 (AOUT32_USRSTACK - sizeof(struct freebsd32_ps_strings))
112 #define AOUT32_MINUSER FREEBSD32_MINUSER
113
114 extern const char *freebsd32_syscallnames[];
115 extern u_long ia32_maxssiz;
116
117 struct sysentvec aout_sysvec = {
118 .sv_size = FREEBSD32_SYS_MAXSYSCALL,
119 .sv_table = freebsd32_sysent,
120 .sv_transtrap = NULL,
121 .sv_fixup = aout_fixup,
122 .sv_sendsig = ia32_sendsig,
123 .sv_sigcode = ia32_sigcode,
124 .sv_szsigcode = &sz_ia32_sigcode,
125 .sv_name = "FreeBSD a.out",
126 .sv_coredump = NULL,
127 .sv_imgact_try = NULL,
128 .sv_minsigstksz = MINSIGSTKSZ,
129 .sv_minuser = AOUT32_MINUSER,
130 .sv_maxuser = AOUT32_USRSTACK,
131 .sv_usrstack = AOUT32_USRSTACK,
132 .sv_psstrings = AOUT32_PS_STRINGS,
133 .sv_stackprot = VM_PROT_ALL,
134 .sv_copyout_strings = freebsd32_copyout_strings,
135 .sv_setregs = ia32_setregs,
136 .sv_fixlimit = ia32_fixlimit,
137 .sv_maxssiz = &ia32_maxssiz,
138 .sv_flags = SV_ABI_FREEBSD | SV_AOUT | SV_IA32 | SV_ILP32,
139 .sv_set_syscall_retval = ia32_set_syscall_retval,
140 .sv_fetch_syscall_args = ia32_fetch_syscall_args,
141 .sv_syscallnames = freebsd32_syscallnames,
142 .sv_onexec_old = exec_onexec_old,
143 .sv_onexit = exit_onexit,
144 };
145 #else
146 #error "Only ia32 arch is supported"
147 #endif
148
149 static int
150 aout_fixup(uintptr_t *stack_base, struct image_params *imgp)
151 {
152
153 *stack_base -= sizeof(uint32_t);
154 if (suword32((void *)*stack_base, imgp->args->argc) != 0)
155 return (EFAULT);
156 return (0);
157 }
158
159 static int
160 exec_aout_imgact(struct image_params *imgp)
161 {
162 const struct exec *a_out;
163 struct vmspace *vmspace;
164 vm_map_t map;
165 vm_object_t object;
166 vm_offset_t text_end, data_end;
167 unsigned long virtual_offset;
168 unsigned long file_offset;
169 unsigned long bss_size;
170 int error;
171
172 a_out = (const struct exec *)imgp->image_header;
173
174 /*
175 * Linux and *BSD binaries look very much alike,
176 * only the machine id is different:
177 * 0x64 for Linux, 0x86 for *BSD, 0x00 for BSDI.
178 * NetBSD is in network byte order.. ugh.
179 */
180 if (((a_out->a_midmag >> 16) & 0xff) != 0x86 &&
181 ((a_out->a_midmag >> 16) & 0xff) != 0 &&
182 ((((int)ntohl(a_out->a_midmag)) >> 16) & 0xff) != 0x86)
183 return (-1);
184
185 /*
186 * Set file/virtual offset based on a.out variant.
187 * We do two cases: host byte order and network byte order
188 * (for NetBSD compatibility)
189 */
190 switch ((int)(a_out->a_midmag & 0xffff)) {
191 case ZMAGIC:
192 virtual_offset = 0;
193 if (a_out->a_text) {
194 file_offset = PAGE_SIZE;
195 } else {
196 /* Bill's "screwball mode" */
197 file_offset = 0;
198 }
199 break;
200 case QMAGIC:
201 virtual_offset = PAGE_SIZE;
202 file_offset = 0;
203 /* Pass PS_STRINGS for BSD/OS binaries only. */
204 if (N_GETMID(*a_out) == MID_ZERO)
205 imgp->ps_strings = (void *)aout_sysvec.sv_psstrings;
206 break;
207 default:
208 /* NetBSD compatibility */
209 switch ((int)(ntohl(a_out->a_midmag) & 0xffff)) {
210 case ZMAGIC:
211 case QMAGIC:
212 virtual_offset = PAGE_SIZE;
213 file_offset = 0;
214 break;
215 default:
216 return (-1);
217 }
218 }
219
220 bss_size = roundup(a_out->a_bss, PAGE_SIZE);
221
222 /*
223 * Check various fields in header for validity/bounds.
224 */
225 if (/* entry point must lay with text region */
226 a_out->a_entry < virtual_offset ||
227 a_out->a_entry >= virtual_offset + a_out->a_text ||
228
229 /* text and data size must each be page rounded */
230 a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK
231
232 #ifdef __amd64__
233 ||
234 /* overflows */
235 virtual_offset + a_out->a_text + a_out->a_data + bss_size > UINT_MAX
236 #endif
237 )
238 return (-1);
239
240 /* text + data can't exceed file size */
241 if (a_out->a_data + a_out->a_text > imgp->attr->va_size)
242 return (EFAULT);
243
244 /*
245 * text/data/bss must not exceed limits
246 */
247 PROC_LOCK(imgp->proc);
248 if (/* text can't exceed maximum text size */
249 a_out->a_text > maxtsiz ||
250
251 /* data + bss can't exceed rlimit */
252 a_out->a_data + bss_size > lim_cur_proc(imgp->proc, RLIMIT_DATA) ||
253 racct_set(imgp->proc, RACCT_DATA, a_out->a_data + bss_size) != 0) {
254 PROC_UNLOCK(imgp->proc);
255 return (ENOMEM);
256 }
257 PROC_UNLOCK(imgp->proc);
258
259 /*
260 * Avoid a possible deadlock if the current address space is destroyed
261 * and that address space maps the locked vnode. In the common case,
262 * the locked vnode's v_usecount is decremented but remains greater
263 * than zero. Consequently, the vnode lock is not needed by vrele().
264 * However, in cases where the vnode lock is external, such as nullfs,
265 * v_usecount may become zero.
266 */
267 VOP_UNLOCK(imgp->vp);
268
269 /*
270 * Destroy old process VM and create a new one (with a new stack)
271 */
272 error = exec_new_vmspace(imgp, &aout_sysvec);
273
274 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
275 if (error)
276 return (error);
277
278 /*
279 * The vm space can be changed by exec_new_vmspace
280 */
281 vmspace = imgp->proc->p_vmspace;
282
283 object = imgp->object;
284 map = &vmspace->vm_map;
285 vm_map_lock(map);
286 vm_object_reference(object);
287
288 text_end = virtual_offset + a_out->a_text;
289 error = vm_map_insert(map, object,
290 file_offset,
291 virtual_offset, text_end,
292 VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
293 MAP_COPY_ON_WRITE | MAP_PREFAULT | MAP_VN_EXEC);
294 if (error) {
295 vm_map_unlock(map);
296 vm_object_deallocate(object);
297 return (error);
298 }
299 VOP_SET_TEXT_CHECKED(imgp->vp);
300 data_end = text_end + a_out->a_data;
301 if (a_out->a_data) {
302 vm_object_reference(object);
303 error = vm_map_insert(map, object,
304 file_offset + a_out->a_text,
305 text_end, data_end,
306 VM_PROT_ALL, VM_PROT_ALL,
307 MAP_COPY_ON_WRITE | MAP_PREFAULT | MAP_VN_EXEC);
308 if (error) {
309 vm_map_unlock(map);
310 vm_object_deallocate(object);
311 return (error);
312 }
313 VOP_SET_TEXT_CHECKED(imgp->vp);
314 }
315
316 if (bss_size) {
317 error = vm_map_insert(map, NULL, 0,
318 data_end, data_end + bss_size,
319 VM_PROT_ALL, VM_PROT_ALL, 0);
320 if (error) {
321 vm_map_unlock(map);
322 return (error);
323 }
324 }
325 vm_map_unlock(map);
326
327 /* Fill in process VM information */
328 vmspace->vm_tsize = a_out->a_text >> PAGE_SHIFT;
329 vmspace->vm_dsize = (a_out->a_data + bss_size) >> PAGE_SHIFT;
330 vmspace->vm_taddr = (caddr_t) (uintptr_t) virtual_offset;
331 vmspace->vm_daddr = (caddr_t) (uintptr_t)
332 (virtual_offset + a_out->a_text);
333
334 /* Fill in image_params */
335 imgp->interpreted = 0;
336 imgp->entry_addr = a_out->a_entry;
337
338 imgp->proc->p_sysent = &aout_sysvec;
339
340 return (0);
341 }
342
343 /*
344 * Tell kern_execve.c about it, with a little help from the linker.
345 */
346 static struct execsw aout_execsw = {
347 .ex_imgact = exec_aout_imgact,
348 .ex_name = "a.out"
349 };
350 EXEC_SET(aout, aout_execsw);
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