1  /*-
  2   * Copyright (c) 2006,2008 Joseph Koshy
  3   * All rights reserved.
  4   *
  5   * Redistribution and use in source and binary forms, with or without
  6   * modification, are permitted provided that the following conditions
  7   * are met:
  8   * 1. Redistributions of source code must retain the above copyright
  9   *    notice, this list of conditions and the following disclaimer.
 10   * 2. Redistributions in binary form must reproduce the above copyright
 11   *    notice, this list of conditions and the following disclaimer in the
 12   *    documentation and/or other materials provided with the distribution.
 13   *
 14   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 15   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 16   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 17   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 18   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 19   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 20   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 21   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 22   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 23   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 24   * SUCH DAMAGE.
 25   */
 26  
 27  #include <sys/cdefs.h>
 28  
 29  #include <assert.h>
 30  #include <gelf.h>
 31  #include <limits.h>
 32  
 33  #include "_libelf.h"
 34  
 35  ELFTC_VCSID("$Id$");
 36  
 37  GElf_Rela *
 38  gelf_getrela(Elf_Data *ed, int ndx, GElf_Rela *dst)
 39  {
 40  	int ec;
 41  	Elf *e;
 42  	size_t msz;
 43  	Elf_Scn *scn;
 44  	uint32_t sh_type;
 45  	Elf32_Rela *rela32;
 46  	Elf64_Rela *rela64;
 47  	struct _Libelf_Data *d;
 48  
 49  	d = (struct _Libelf_Data *) ed;
 50  
 51  	if (d == NULL || ndx < 0 || dst == NULL ||
 52  	    (scn = d->d_scn) == NULL ||
 53  	    (e = scn->s_elf) == NULL) {
 54  		LIBELF_SET_ERROR(ARGUMENT, 0);
 55  		return (NULL);
 56  	}
 57  
 58  	ec = e->e_class;
 59  	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
 60  
 61  	if (ec == ELFCLASS32)
 62  		sh_type = scn->s_shdr.s_shdr32.sh_type;
 63  	else
 64  		sh_type = scn->s_shdr.s_shdr64.sh_type;
 65  
 66  	if (_libelf_xlate_shtype(sh_type) != ELF_T_RELA) {
 67  		LIBELF_SET_ERROR(ARGUMENT, 0);
 68  		return (NULL);
 69  	}
 70  
 71  	msz = _libelf_msize(ELF_T_RELA, ec, e->e_version);
 72  
 73  	assert(msz > 0);
 74  	assert(ndx >= 0);
 75  
 76  	if (msz * (size_t) ndx >= d->d_data.d_size) {
 77  		LIBELF_SET_ERROR(ARGUMENT, 0);
 78  		return (NULL);
 79  	}
 80  
 81  	if (ec == ELFCLASS32) {
 82  		rela32 = (Elf32_Rela *) d->d_data.d_buf + ndx;
 83  
 84  		dst->r_offset = (Elf64_Addr) rela32->r_offset;
 85  		dst->r_info   = ELF64_R_INFO(
 86  		    (Elf64_Xword) ELF32_R_SYM(rela32->r_info),
 87  		    ELF32_R_TYPE(rela32->r_info));
 88  		dst->r_addend = (Elf64_Sxword) rela32->r_addend;
 89  
 90  	} else {
 91  
 92  		rela64 = (Elf64_Rela *) d->d_data.d_buf + ndx;
 93  
 94  		*dst = *rela64;
 95  	}
 96  
 97  	return (dst);
 98  }
 99  
100  int
101  gelf_update_rela(Elf_Data *ed, int ndx, GElf_Rela *dr)
102  {
103  	int ec;
104  	Elf *e;
105  	size_t msz;
106  	Elf_Scn *scn;
107  	uint32_t sh_type;
108  	Elf32_Rela *rela32;
109  	Elf64_Rela *rela64;
110  	struct _Libelf_Data *d;
111  
112  	d = (struct _Libelf_Data *) ed;
113  
114  	if (d == NULL || ndx < 0 || dr == NULL ||
115  	    (scn = d->d_scn) == NULL ||
116  	    (e = scn->s_elf) == NULL) {
117  		LIBELF_SET_ERROR(ARGUMENT, 0);
118  		return (0);
119  	}
120  
121  	ec = e->e_class;
122  	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
123  
124  	if (ec == ELFCLASS32)
125  		sh_type = scn->s_shdr.s_shdr32.sh_type;
126  	else
127  		sh_type = scn->s_shdr.s_shdr64.sh_type;
128  
129  	if (_libelf_xlate_shtype(sh_type) != ELF_T_RELA) {
130  		LIBELF_SET_ERROR(ARGUMENT, 0);
131  		return (0);
132  	}
133  
134  	msz = _libelf_msize(ELF_T_RELA, ec, e->e_version);
135  
136  	assert(msz > 0);
137  	assert(ndx >= 0);
138  
139  	if (msz * (size_t) ndx >= d->d_data.d_size) {
140  		LIBELF_SET_ERROR(ARGUMENT, 0);
141  		return (0);
142  	}
143  
144  	if (ec == ELFCLASS32) {
145  		rela32 = (Elf32_Rela *) d->d_data.d_buf + ndx;
146  
147  		LIBELF_COPY_U32(rela32, dr, r_offset);
148  
149  		if (ELF64_R_SYM(dr->r_info) > ELF32_R_SYM(~0UL) ||
150  		    ELF64_R_TYPE(dr->r_info) > ELF32_R_TYPE(~0U)) {
151  			LIBELF_SET_ERROR(RANGE, 0);
152  			return (0);
153  		}
154  		rela32->r_info = ELF32_R_INFO(
155  			(Elf32_Word) ELF64_R_SYM(dr->r_info),
156  			(Elf32_Word) ELF64_R_TYPE(dr->r_info));
157  
158  		LIBELF_COPY_S32(rela32, dr, r_addend);
159  	} else {
160  		rela64 = (Elf64_Rela *) d->d_data.d_buf + ndx;
161  
162  		*rela64 = *dr;
163  	}
164  
165  	return (1);
166  }