NetBSD/usr.bin/crunch/crunchide/exec_elf32.c

387 lines
9.9 KiB
C

/* $NetBSD: exec_elf32.c,v 1.4 1997/08/12 06:07:24 mikel Exp $ */
/*
* Copyright (c) 1997 Christopher G. Demetriou. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Christopher G. Demetriou
* for the NetBSD Project.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: exec_elf32.c,v 1.4 1997/08/12 06:07:24 mikel Exp $");
#endif
#ifndef ELFSIZE
#define ELFSIZE 32
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "extern.h"
#if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \
(defined(NLIST_ELF64) && (ELFSIZE == 64))
#include <sys/exec_elf.h>
#define CONCAT(x,y) __CONCAT(x,y)
#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x)))
#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y))))
#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE))
#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))
struct listelem {
struct listelem *next;
void *mem;
off_t file;
size_t size;
};
static ssize_t
xreadatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
{
ssize_t rv;
if (lseek(fd, off, SEEK_SET) != off) {
perror(fn);
return -1;
}
if ((rv = read(fd, buf, size)) != size) {
fprintf(stderr, "%s: read error: %s\n", fn,
rv == -1 ? strerror(errno) : "short read");
return -1;
}
return size;
}
static ssize_t
xwriteatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
{
ssize_t rv;
if (lseek(fd, off, SEEK_SET) != off) {
perror(fn);
return -1;
}
if ((rv = write(fd, buf, size)) != size) {
fprintf(stderr, "%s: write error: %s\n", fn,
rv == -1 ? strerror(errno) : "short write");
return -1;
}
return size;
}
static void *
xmalloc(size_t size, const char *fn, const char *use)
{
void *rv;
rv = malloc(size);
if (rv == NULL)
fprintf(stderr, "%s: out of memory (allocating for %s)\n",
fn, use);
return (rv);
}
int
ELFNAMEEND(check)(int fd, const char *fn)
{
Elf_Ehdr eh;
struct stat sb;
/*
* Check the header to maek sure it's an ELF file (of the
* appropriate size).
*/
if (fstat(fd, &sb) == -1)
return 0;
if (sb.st_size < sizeof eh)
return 0;
if (read(fd, &eh, sizeof eh) != sizeof eh)
return 0;
if (memcmp(eh.e_ident, Elf_e_ident, Elf_e_siz))
return 0;
switch (eh.e_machine) {
ELFDEFNNAME(MACHDEP_ID_CASES)
default:
return 0;
}
return 1;
}
int
ELFNAMEEND(hide)(int fd, const char *fn)
{
Elf_Ehdr ehdr;
Elf_Shdr *shdrp = NULL, *symtabshdr, *strtabshdr;
Elf_Sym *symtabp = NULL;
char *strtabp = NULL;
Elf_Word *symfwmap = NULL, *symrvmap = NULL, nsyms, nlocalsyms, ewi;
struct listelem *relalist = NULL, *rellist = NULL, *tmpl;
ssize_t shdrsize;
int rv, i, weird;
rv = 0;
if (xreadatoff(fd, &ehdr, 0, sizeof ehdr, fn) != sizeof ehdr)
goto bad;
shdrsize = ehdr.e_shnum * ehdr.e_shentsize;
if ((shdrp = xmalloc(shdrsize, fn, "section header table")) == NULL)
goto bad;
if (xreadatoff(fd, shdrp, ehdr.e_shoff, shdrsize, fn) != shdrsize)
goto bad;
symtabshdr = strtabshdr = NULL;
weird = 0;
for (i = 0; i < ehdr.e_shnum; i++) {
switch (shdrp[i].sh_type) {
case Elf_sht_symtab:
if (symtabshdr != NULL)
weird = 1;
symtabshdr = &shdrp[i];
strtabshdr = &shdrp[shdrp[i].sh_link];
break;
case Elf_sht_rela:
tmpl = xmalloc(sizeof *tmpl, fn, "rela list element");
if (tmpl == NULL)
goto bad;
tmpl->mem = NULL;
tmpl->file = shdrp[i].sh_offset;
tmpl->size = shdrp[i].sh_size;
tmpl->next = relalist;
relalist = tmpl;
break;
case Elf_sht_rel:
tmpl = xmalloc(sizeof *tmpl, fn, "rel list element");
if (tmpl == NULL)
goto bad;
tmpl->mem = NULL;
tmpl->file = shdrp[i].sh_offset;
tmpl->size = shdrp[i].sh_size;
tmpl->next = rellist;
rellist = tmpl;
break;
}
}
if (symtabshdr == NULL)
goto out;
if (strtabshdr == NULL)
weird = 1;
if (weird) {
fprintf(stderr, "%s: weird executable (unsupported)\n", fn);
goto bad;
}
/*
* load up everything we need
*/
/* symbol table */
if ((symtabp = xmalloc(symtabshdr->sh_size, fn, "symbol table"))
== NULL)
goto bad;
if (xreadatoff(fd, symtabp, symtabshdr->sh_offset, symtabshdr->sh_size,
fn) != symtabshdr->sh_size)
goto bad;
/* string table */
if ((strtabp = xmalloc(strtabshdr->sh_size, fn, "string table"))
== NULL)
goto bad;
if (xreadatoff(fd, strtabp, strtabshdr->sh_offset, strtabshdr->sh_size,
fn) != strtabshdr->sh_size)
goto bad;
/* any rela tables */
for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
if ((tmpl->mem = xmalloc(tmpl->size, fn, "rela table"))
== NULL)
goto bad;
if (xreadatoff(fd, tmpl->mem, tmpl->file, tmpl->size, fn) !=
tmpl->size)
goto bad;
}
/* any rel tables */
for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
if ((tmpl->mem = xmalloc(tmpl->size, fn, "rel table"))
== NULL)
goto bad;
if (xreadatoff(fd, tmpl->mem, tmpl->file, tmpl->size, fn) !=
tmpl->size)
goto bad;
}
/* Prepare data structures for symbol movement. */
nsyms = symtabshdr->sh_size / symtabshdr->sh_entsize;
nlocalsyms = symtabshdr->sh_info;
if ((symfwmap = xmalloc(nsyms * sizeof (Elf_Word), fn,
"symbol forward mapping table")) == NULL)
goto bad;
if ((symrvmap = xmalloc(nsyms * sizeof (Elf_Word), fn,
"symbol reverse mapping table")) == NULL)
goto bad;
/* init location -> symbol # table */
for (ewi = 0; ewi < nsyms; ewi++)
symrvmap[ewi] = ewi;
/* move symbols, making them local */
for (ewi = nlocalsyms; ewi < nsyms; ewi++) {
Elf_Sym *sp, symswap;
Elf_Word mapswap;
sp = &symtabp[ewi];
/* if it's on our keep list, don't move it */
if (in_keep_list(strtabp + sp->st_name))
continue;
/* if it's an undefined symbol, keep it */
if (sp->st_shndx == Elf_eshn_undefined)
continue;
/* adjust the symbol so that it's local */
sp->st_info =
(Elf_estb_local << 4) | ELF_SYM_TYPE(sp->st_info); /* XXX */
/*
* move the symbol to its new location
*/
/* note that symbols in those locations have been swapped */
mapswap = symrvmap[ewi];
symrvmap[ewi] = symrvmap[nlocalsyms];
symrvmap[nlocalsyms] = mapswap;
/* and swap the symbols */
symswap = *sp;
*sp = symtabp[nlocalsyms];
symtabp[nlocalsyms] = symswap;
nlocalsyms++; /* note new local sym */
}
symtabshdr->sh_info = nlocalsyms;
/* set up symbol # -> location mapping table */
for (ewi = 0; ewi < nsyms; ewi++)
symfwmap[symrvmap[ewi]] = ewi;
/* any rela tables */
for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
Elf_RelA *relap = tmpl->mem;
for (ewi = 0; ewi < tmpl->size / sizeof *relap; ewi++) {
relap[ewi].r_info =
#if (ELFSIZE == 32) /* XXX */
symfwmap[ELF_R_SYM(relap[ewi].r_info)] << 8 |
ELF_R_TYPE(relap[ewi].r_info);
#elif (ELFSIZE == 64) /* XXX */
symfwmap[ELF_R_SYM(relap[ewi].r_info)] << 32 |
ELF_R_TYPE(relap[ewi].r_info);
#endif /* XXX */
}
}
/* any rel tables */
for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
Elf_Rel *relp = tmpl->mem;
for (ewi = 0; ewi < tmpl->size / sizeof *relp; ewi++) {
relp[ewi].r_info =
#if (ELFSIZE == 32) /* XXX */
symfwmap[ELF_R_SYM(relp[ewi].r_info)] << 8 |
ELF_R_TYPE(relp[ewi].r_info);
#elif (ELFSIZE == 64) /* XXX */
symfwmap[ELF_R_SYM(relp[ewi].r_info)] << 32 |
ELF_R_TYPE(relp[ewi].r_info);
#endif /* XXX */
}
}
/*
* write new tables to the file
*/
if (xwriteatoff(fd, shdrp, ehdr.e_shoff, shdrsize, fn) != shdrsize)
goto bad;
if (xwriteatoff(fd, symtabp, symtabshdr->sh_offset,
symtabshdr->sh_size, fn) != symtabshdr->sh_size)
goto bad;
for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
if (xwriteatoff(fd, tmpl->mem, tmpl->file, tmpl->size, fn) !=
tmpl->size)
goto bad;
}
for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
if (xwriteatoff(fd, tmpl->mem, tmpl->file, tmpl->size, fn) !=
tmpl->size)
goto bad;
}
out:
if (shdrp != NULL)
free(shdrp);
if (symtabp != NULL)
free(symtabp);
if (strtabp != NULL)
free(strtabp);
if (symfwmap != NULL)
free(symfwmap);
if (symrvmap != NULL)
free(symrvmap);
while ((tmpl = relalist) != NULL) {
relalist = tmpl->next;
if (tmpl->mem != NULL)
free(tmpl->mem);
free(tmpl);
}
while ((tmpl = rellist) != NULL) {
rellist = tmpl->next;
if (tmpl->mem != NULL)
free(tmpl->mem);
free(tmpl);
}
return (rv);
bad:
rv = 1;
goto out;
}
#endif /* include this size of ELF */