xref: /freebsd/sys/i386/linux/imgact_linux.c (revision e6bfd18d21b225af6a0ed67ceeaf1293b7b9eba5)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1994-1996 Søren Schmidt
5  * All rights reserved.
6  *
7  * Based heavily on /sys/kern/imgact_aout.c which is:
8  * Copyright (c) 1993, David Greenman
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/exec.h>
38 #include <sys/imgact.h>
39 #include <sys/imgact_aout.h>
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/mman.h>
43 #include <sys/mutex.h>
44 #include <sys/proc.h>
45 #include <sys/racct.h>
46 #include <sys/resourcevar.h>
47 #include <sys/vnode.h>
48 
49 #include <vm/vm.h>
50 #include <vm/vm_kern.h>
51 #include <vm/vm_param.h>
52 #include <vm/pmap.h>
53 #include <vm/vm_map.h>
54 #include <vm/vm_extern.h>
55 
56 #include <i386/linux/linux.h>
57 
58 static int	exec_linux_imgact(struct image_params *iparams);
59 
60 static int
61 exec_linux_imgact(struct image_params *imgp)
62 {
63 	const struct exec *a_out = (const struct exec *) imgp->image_header;
64 	struct vmspace *vmspace;
65 	vm_offset_t vmaddr;
66 	unsigned long virtual_offset, file_offset;
67 	unsigned long bss_size;
68 	ssize_t aresid;
69 	int error;
70 
71 	if (((a_out->a_magic >> 16) & 0xff) != 0x64)
72 		return (-1);
73 
74 	/*
75 	 * Set file/virtual offset based on a.out variant.
76 	 */
77 	switch ((int)(a_out->a_magic & 0xffff)) {
78 	case 0413:
79 		virtual_offset = 0;
80 		file_offset = 1024;
81 		break;
82 	case 0314:
83 		virtual_offset = 4096;
84 		file_offset = 0;
85 		break;
86 	default:
87 		return (-1);
88 	}
89 	bss_size = round_page(a_out->a_bss);
90 #ifdef DEBUG
91 	printf("imgact: text: %08lx, data: %08lx, bss: %08lx\n",
92 	    (u_long)a_out->a_text, (u_long)a_out->a_data, bss_size);
93 #endif
94 
95 	/*
96 	 * Check various fields in header for validity/bounds.
97 	 */
98 	if (a_out->a_entry < virtual_offset ||
99 	    a_out->a_entry >= virtual_offset + a_out->a_text ||
100 	    a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK)
101 		return (-1);
102 
103 	/* text + data can't exceed file size */
104 	if (a_out->a_data + a_out->a_text > imgp->attr->va_size)
105 		return (EFAULT);
106 	/*
107 	 * text/data/bss must not exceed limits
108 	 */
109 	PROC_LOCK(imgp->proc);
110 	if (a_out->a_text > maxtsiz ||
111 	    a_out->a_data + bss_size > lim_cur_proc(imgp->proc, RLIMIT_DATA) ||
112 	    racct_set(imgp->proc, RACCT_DATA, a_out->a_data + bss_size) != 0) {
113 		PROC_UNLOCK(imgp->proc);
114 		return (ENOMEM);
115 	}
116 	PROC_UNLOCK(imgp->proc);
117 
118 	VOP_UNLOCK(imgp->vp);
119 
120 	/*
121 	 * Destroy old process VM and create a new one (with a new stack)
122 	 */
123 	error = exec_new_vmspace(imgp, &linux_sysvec);
124 	if (error)
125 		goto fail;
126 	vmspace = imgp->proc->p_vmspace;
127 
128 	/*
129 	 * Check if file_offset page aligned,.
130 	 * Currently we cannot handle misaligned file offsets,
131 	 * and so we read in the entire image (what a waste).
132 	 */
133 	if (file_offset & PAGE_MASK) {
134 #ifdef DEBUG
135 		printf("imgact: Non page aligned binary %lu\n", file_offset);
136 #endif
137 		/*
138 		 * Map text+data+bss read/write/execute
139 		 */
140 		vmaddr = virtual_offset;
141 		error = vm_map_find(&vmspace->vm_map, NULL, 0, &vmaddr,
142 		    a_out->a_text + a_out->a_data + bss_size, 0, VMFS_NO_SPACE,
143 		    VM_PROT_ALL, VM_PROT_ALL, 0);
144 		if (error)
145 			goto fail;
146 
147 		error = vn_rdwr(UIO_READ, imgp->vp, (void *)vmaddr, file_offset,
148 		    a_out->a_text + a_out->a_data, UIO_USERSPACE, 0,
149 		    curthread->td_ucred, NOCRED, &aresid, curthread);
150 		if (error != 0)
151 			goto fail;
152 		if (aresid != 0) {
153 			error = ENOEXEC;
154 			goto fail;
155 		}
156 
157 		/*
158 		 * remove write enable on the 'text' part
159 		 */
160 		error = vm_map_protect(&vmspace->vm_map, vmaddr,
161 		    vmaddr + a_out->a_text, 0, VM_PROT_EXECUTE | VM_PROT_READ,
162 		    VM_MAP_PROTECT_SET_MAXPROT);
163 		if (error)
164 			goto fail;
165 	} else {
166 #ifdef DEBUG
167 		printf("imgact: Page aligned binary %lu\n", file_offset);
168 #endif
169 		/*
170 		 * Map text+data read/execute
171 		 */
172 		vmaddr = virtual_offset;
173 		error = vm_mmap(&vmspace->vm_map, &vmaddr,
174 		    a_out->a_text + a_out->a_data,
175 		    VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
176 		    MAP_PRIVATE | MAP_FIXED, OBJT_VNODE, imgp->vp, file_offset);
177 		if (error)
178 			goto fail;
179 
180 #ifdef DEBUG
181 		printf("imgact: startaddr=%08lx, length=%08lx\n",
182 		    (u_long)vmaddr,
183 		    (u_long)a_out->a_text + (u_long)a_out->a_data);
184 #endif
185 		/*
186 		 * allow read/write of data
187 		 */
188 		error = vm_map_protect(&vmspace->vm_map, vmaddr + a_out->a_text,
189 		    vmaddr + a_out->a_text + a_out->a_data, VM_PROT_ALL, 0,
190 		    VM_MAP_PROTECT_SET_PROT);
191 		if (error)
192 			goto fail;
193 
194 		/*
195 		 * Allocate anon demand-zeroed area for uninitialized data
196 		 */
197 		if (bss_size != 0) {
198 			vmaddr = virtual_offset + a_out->a_text + a_out->a_data;
199 		error = vm_map_find(&vmspace->vm_map, NULL, 0, &vmaddr,
200 		    bss_size, 0, VMFS_NO_SPACE, VM_PROT_ALL, VM_PROT_ALL, 0);
201 		if (error)
202 			goto fail;
203 #ifdef DEBUG
204 		printf("imgact: bssaddr=%08lx, length=%08lx\n", (u_long)vmaddr,
205 		    bss_size);
206 #endif
207 		}
208 	}
209 	/* Fill in process VM information */
210 	vmspace->vm_tsize = round_page(a_out->a_text) >> PAGE_SHIFT;
211 	vmspace->vm_dsize = round_page(a_out->a_data + bss_size) >> PAGE_SHIFT;
212 	vmspace->vm_taddr = (caddr_t)(void *)(uintptr_t)virtual_offset;
213 	vmspace->vm_daddr =
214 	    (caddr_t)(void *)(uintptr_t)(virtual_offset + a_out->a_text);
215 
216 	error = exec_map_stack(imgp);
217 	if (error != 0)
218 		goto fail;
219 
220 	/* Fill in image_params */
221 	imgp->interpreted = 0;
222 	imgp->entry_addr = a_out->a_entry;
223 
224 	imgp->proc->p_sysent = &linux_sysvec;
225 
226 fail:
227 	vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
228 	return (error);
229 }
230 
231 /*
232  * Tell kern_execve.c about it, with a little help from the linker.
233  */
234 static struct execsw linux_execsw = { exec_linux_imgact, "Linux a.out" };
235 EXEC_SET(linuxaout, linux_execsw);
236