xref: /freebsd/stand/common/reloc_elf.c (revision d0b2dbfa)
1 /*-
2  * Copyright (c) 2003 Jake Burkholder.
3  * Copyright 1996-1998 John D. Polstra.
4  * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
5  * Copyright (c) 1998 Peter Wemm <peter@freebsd.org>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 #include <sys/types.h>
32 #include <machine/elf.h>
33 
34 #include <stand.h>
35 
36 #define FREEBSD_ELF
37 #include <sys/link_elf.h>
38 
39 #include "bootstrap.h"
40 
41 #define COPYOUT(s,d,l)	archsw.arch_copyout((vm_offset_t)(s), d, l)
42 
43 /*
44  * Apply a single intra-module relocation to the data. `relbase' is the
45  * target relocation base for the section (i.e. it corresponds to where
46  * r_offset == 0). `dataaddr' is the relocated address corresponding to
47  * the start of the data, and `len' is the number of bytes.
48  */
49 int
50 __elfN(reloc)(struct elf_file *ef, symaddr_fn *symaddr, const void *reldata,
51     int reltype, Elf_Addr relbase, Elf_Addr dataaddr, void *data, size_t len)
52 {
53 #if (defined(__aarch64__) || defined(__amd64__) || defined(__i386__)) && \
54     __ELF_WORD_SIZE == 64
55 	Elf64_Addr *where, val;
56 	Elf_Addr addend, addr;
57 	Elf_Size rtype;
58 #if defined(__amd64__) || defined(__i386__)
59 	Elf_Size symidx;
60 #endif
61 	const Elf_Rel *rel;
62 	const Elf_Rela *rela;
63 
64 	switch (reltype) {
65 	case ELF_RELOC_REL:
66 		rel = (const Elf_Rel *)reldata;
67 		where = (Elf_Addr *)((char *)data + relbase + rel->r_offset -
68 		    dataaddr);
69 		addend = 0;
70 		rtype = ELF_R_TYPE(rel->r_info);
71 #if defined(__amd64__) || defined(__i386__)
72 		symidx = ELF_R_SYM(rel->r_info);
73 #endif
74 		addend = 0;
75 		break;
76 	case ELF_RELOC_RELA:
77 		rela = (const Elf_Rela *)reldata;
78 		where = (Elf_Addr *)((char *)data + relbase + rela->r_offset -
79 		    dataaddr);
80 		addend = rela->r_addend;
81 		rtype = ELF_R_TYPE(rela->r_info);
82 #if defined(__amd64__) || defined(__i386__)
83 		symidx = ELF_R_SYM(rela->r_info);
84 #endif
85 		break;
86 	default:
87 		return (EINVAL);
88 	}
89 
90 	if ((char *)where < (char *)data || (char *)where >= (char *)data + len)
91 		return (0);
92 
93 	if (reltype == ELF_RELOC_REL)
94 		addend = *where;
95 
96 #if defined(__aarch64__)
97 #define	RELOC_RELATIVE		R_AARCH64_RELATIVE
98 #define	RELOC_IRELATIVE		R_AARCH64_IRELATIVE
99 #elif defined(__amd64__) || defined(__i386__)
100 /* XXX, definitions not available on i386. */
101 #define	R_X86_64_64		1
102 #define	R_X86_64_RELATIVE	8
103 #define	R_X86_64_IRELATIVE	37
104 
105 #define	RELOC_RELATIVE		R_X86_64_RELATIVE
106 #define	RELOC_IRELATIVE		R_X86_64_IRELATIVE
107 #endif
108 
109 	switch (rtype) {
110 	case RELOC_RELATIVE:
111 		addr = (Elf_Addr)addend + relbase;
112 		val = addr;
113 		memcpy(where, &val, sizeof(val));
114 		break;
115 	case RELOC_IRELATIVE:
116 		/* leave it to kernel */
117 		break;
118 #if defined(__amd64__) || defined(__i386__)
119 	case R_X86_64_64:		/* S + A */
120 		addr = symaddr(ef, symidx);
121 		if (addr == 0)
122 			return (ESRCH);
123 		val = addr + addend;
124 		*where = val;
125 		break;
126 #endif
127 	default:
128 		printf("\nunhandled relocation type %u\n", (u_int)rtype);
129 		return (EFTYPE);
130 	}
131 
132 	return (0);
133 #elif defined(__i386__) && __ELF_WORD_SIZE == 32
134 	Elf_Addr addend, addr, *where, val;
135 	Elf_Size rtype, symidx;
136 	const Elf_Rel *rel;
137 	const Elf_Rela *rela;
138 
139 	switch (reltype) {
140 	case ELF_RELOC_REL:
141 		rel = (const Elf_Rel *)reldata;
142 		where = (Elf_Addr *)((char *)data + relbase + rel->r_offset -
143 		    dataaddr);
144 		addend = 0;
145 		rtype = ELF_R_TYPE(rel->r_info);
146 		symidx = ELF_R_SYM(rel->r_info);
147 		addend = 0;
148 		break;
149 	case ELF_RELOC_RELA:
150 		rela = (const Elf_Rela *)reldata;
151 		where = (Elf_Addr *)((char *)data + relbase + rela->r_offset -
152 		    dataaddr);
153 		addend = rela->r_addend;
154 		rtype = ELF_R_TYPE(rela->r_info);
155 		symidx = ELF_R_SYM(rela->r_info);
156 		break;
157 	default:
158 		return (EINVAL);
159 	}
160 
161 	if ((char *)where < (char *)data || (char *)where >= (char *)data + len)
162 		return (0);
163 
164 	if (reltype == ELF_RELOC_REL)
165 		addend = *where;
166 
167 /* XXX, definitions not available on amd64. */
168 #define R_386_32	1	/* Add symbol value. */
169 #define R_386_GLOB_DAT	6	/* Set GOT entry to data address. */
170 #define R_386_RELATIVE	8	/* Add load address of shared object. */
171 #define	R_386_IRELATIVE	42
172 
173 	switch (rtype) {
174 	case R_386_RELATIVE:
175 		addr = addend + relbase;
176 		*where = addr;
177 		break;
178 	case R_386_32:		/* S + A */
179 		addr = symaddr(ef, symidx);
180 		if (addr == 0)
181 			return (ESRCH);
182 		val = addr + addend;
183 		*where = val;
184 		break;
185 	case R_386_IRELATIVE:
186 		/* leave it to kernel */
187 		break;
188 	default:
189 		printf("\nunhandled relocation type %u\n", (u_int)rtype);
190 		return (EFTYPE);
191 	}
192 
193 	return (0);
194 #elif defined(__powerpc__) || defined(__riscv)
195 	Elf_Size w;
196 	const Elf_Rela *rela;
197 
198 	switch (reltype) {
199 	case ELF_RELOC_RELA:
200 		rela = reldata;
201 		if (relbase + rela->r_offset >= dataaddr &&
202 		    relbase + rela->r_offset < dataaddr + len) {
203 			switch (ELF_R_TYPE(rela->r_info)) {
204 #if defined(__powerpc__)
205 			case R_PPC_RELATIVE:
206 #elif defined(__riscv)
207 			case R_RISCV_RELATIVE:
208 #endif
209 				w = relbase + rela->r_addend;
210 				bcopy(&w, (u_char *)data + (relbase +
211 				      rela->r_offset - dataaddr), sizeof(w));
212 				break;
213 			default:
214 				printf("\nunhandled relocation type %u\n",
215 				       (u_int)ELF_R_TYPE(rela->r_info));
216 				return (EFTYPE);
217 			}
218 		}
219 		break;
220 	}
221 
222 	return (0);
223 #else
224 	return (EOPNOTSUPP);
225 #endif
226 }
227