NetBSD/sys/compat/freebsd/freebsd_exec_elf32.c

/*	$NetBSD: freebsd_exec_elf32.c,v 1.17 2007/04/22 08:29:56 dsl Exp $	*/

/*
 * Copyright (c) 1993, 1994 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.
 * 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>
__KERNEL_RCSID(0, "$NetBSD: freebsd_exec_elf32.c,v 1.17 2007/04/22 08:29:56 dsl Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/exec.h>
#ifndef ELFSIZE
#  define ELFSIZE 32
#endif /* !ELFSIZE */
#include <sys/exec_elf.h>

#include <compat/sys/signal.h>
#include <compat/sys/signalvar.h>

#include <compat/freebsd/freebsd_exec.h>
#include <compat/common/compat_util.h>

#include <machine/freebsd_machdep.h>


int
ELFNAME2(freebsd,probe)(
	struct lwp *l,
	struct exec_package *epp,
	void *veh,
	char *itp,
	vaddr_t *pos)
{
	int error;
	size_t i;
	size_t phsize;
	Elf_Ehdr *eh = (Elf_Ehdr *) veh;
	Elf_Phdr *ph;
	Elf_Phdr *ephp;
	Elf_Nhdr *np;

        static const char wantBrand[] = FREEBSD_ELF_BRAND_STRING;
        static const char wantInterp[] = FREEBSD_ELF_INTERP_PREFIX_STRING;

        /*
	 * Insist that the executable have a brand, and that it be "FreeBSD".
	 * Newer FreeBSD binaries have OSABI set to ELFOSABI_FREEBSD. This
	 * is arguably broken, but they seem to think they need it, for
	 * whatever reason.
	 */
#ifndef EI_BRAND
#define EI_BRAND 8
#endif
        if ((eh->e_ident[EI_BRAND] == '\0'
		|| strcmp(&eh->e_ident[EI_BRAND], wantBrand) != 0)
	    && eh->e_ident[EI_OSABI] != ELFOSABI_FREEBSD)
		return ENOEXEC;

	i = eh->e_phnum;
	if (i != 0) {
		phsize = i * sizeof(Elf_Phdr);
		ph = (Elf_Phdr *) malloc(phsize, M_TEMP, M_WAITOK);
		if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph,
		    phsize)) != 0)
			goto bad1;

		for (ephp = ph; i--; ephp++) {
			if (ephp->p_type != PT_INTERP)
				continue;

			/* Check for "legal" intepreter name. */
			if (ephp->p_filesz < sizeof wantInterp)
				goto bad1;

			np = (Elf_Nhdr *) malloc(ephp->p_filesz+1,
			    M_TEMP, M_WAITOK);

			if (((error = exec_read_from(l, epp->ep_vp,
			    ephp->p_offset, np, ephp->p_filesz)) != 0))
				goto bad2;

			if (strncmp((char *)np, wantInterp,
			    sizeof wantInterp - 1))
				goto bad2;

			free(np, M_TEMP);
			break;
		}
		free(ph, M_TEMP);
	}

	if (itp) {
		if ((error = emul_find_interp(l, epp, itp)))
			return error;
	}
#ifdef DEBUG_FREEBSD_ELF
	printf("freebsd_elf32_probe: returning 0\n");
#endif
	return 0;

bad2:
	free(np, M_TEMP);
bad1:
	free(ph, M_TEMP);
	return ENOEXEC;
}